| 1. |
- Bhagavathiachari, Muthuraaman, et al.
(författare)
-
A quasi-liquid polymer-based cobalt redox mediator electrolyte for dye-sensitized solar cells
- 2013
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:40, s. 17419-17425
-
Tidskriftsartikel (refereegranskat)abstract
- Recently, cobalt redox electrolyte mediators have emerged as a promising alternative to the commonly used iodide/triiodide redox shuttle in dye-sensitized solar cells (DSCs). Here, we report the successful use of a new quasi-liquid, polymer-based electrolyte containing the Co3+/Co2+ redox mediator in 3-methoxy propionitrile solvent in order to overcome the limitations of high cell resistance, low diffusion coefficient and rapid recombination losses. The performance of the solar cells containing the polymer based electrolytes increased by a factor of 1.2 with respect to an analogous electrolyte without the polymer. The performances of the fabricated DSCs have been investigated in detail by photovoltaic, transient electron measurements, EIS, Raman and UV-vis spectroscopy. This approach offers an effective way to make high-performance and long-lasting DSCs.
|
|
| 2. |
- Tian, Haining, et al.
(författare)
-
Development of an organic redox couple and organic dyes for aqueous dye-sensitized solar cells
- 2012
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 5:12, s. 9752-9755
-
Tidskriftsartikel (refereegranskat)abstract
- A water-soluble organic redox couple (TT-/DTT) and new organic dyes (D45 and D51) have been developed for aqueous dye-sensitized solar cells (DSCs). An optimal efficiency of 3.5% was obtained using the D51 dye and an optimized electrolyte composition. The highest IPCE value obtained was 68% at 460 nm.
|
|
| 3. |
- Aitola, Kerttu, et al.
(författare)
-
Carbon nanotube film replacing silver in high-efficiency solid-state dye solar cells employing polymer hole conductor
- 2015
-
Ingår i: Journal of Solid State Electrochemistry. - : Springer Science and Business Media LLC. - 1432-8488 .- 1433-0768. ; 19:10, s. 3139-3144
-
Tidskriftsartikel (refereegranskat)abstract
- A semitransparent, flexible single-walled carbon nanotube (SWCNT) film was efficiently used in place of evaporated silver as the counter electrode of a poly(3,4-ethylenedioxythiophene) polymer-based solid-state dye solar cell (SSDSC): the solar-to-electrical energy conversion efficiency of the SWCNT-SSDSC was 4.8 % when it was 5.2 % for the Ag-SSDSC. The efficiency difference stemmed from a 0.1-V difference in the open-circuit voltage, whose reason was speculated to be related to the different recombination processes in the two types of SSDSCs.
|
|
| 4. |
- Bagheri, Narjes, et al.
(författare)
-
Combination of Asymmetric Supercapacitor Utilizing Activated Carbon and Nickel Oxide with Cobalt Polypyridyl-Based Dye-Sensitized Solar Cell
- 2014
-
Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 143, s. 390-397
-
Tidskriftsartikel (refereegranskat)abstract
- A dye-sensitized solar cell (DSC) based on the metal-free organic sensitizer and the cobalt (II, III) polypyridyl electrolyte was integrated here within an asymmetric supercapacitor utilizing cobalt-doped nickel oxide and activated carbon as positive and negative electrodes, respectively. A low cost nickel foil served as intermediate (auxiliary) bifunctional electrode separating two parts of the device and permitting the DSC electrolyte regeneration at one side and charge storage within cobalt-doped nickel oxide at the other. The main purpose of the research was to develop an integrated photocapacitor system capable of both energy generation and its further storage. Following irradiation at the 100 mW cm(-2) level, the solar cell generated an open-circuit voltage of 0.8 V and short-circuit current of 8 mA cm(-2) which corresponds to energy conversion efficiency of 4.9%. It was further shown that upon integration with asymmetric supercapacitor, the photogenerated energy was directly injected into porous charge storage electrodes thus resulting in specific capacitance of 32 F g(-1) and energy density of 2.3 Wh kg(-1). The coulumbic and total (energy conversion and charge storage) efficiency of photocapacitor were equal to 54% and 0.6%, respectively.
|
|
| 5. |
- Bagheri, Narjes, et al.
(författare)
-
Physicochemical identity and charge storage properties of battery-type nickel oxide material and its composites with activated carbon
- 2016
-
Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 194, s. 480-488
-
Tidskriftsartikel (refereegranskat)abstract
- The structural properties of annealed nickel oxide and its composites with activated carbon (synthesized via simple precipitation methods) have been addressed using X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption method and scanning electron microscopy. The charge storage properties of materials have also been investigated in three-and two-electrode configurations by means of cyclic voltammetry and galvanostatic charging/discharging in alkaline media. The results are consistent with the view that, depending on a method of preparation, the resulting nickel oxide films may exhibit redox characteristics different from that typically observed for nickel oxide-based materials. It is demonstrated that faradaic-type (redox) reactions, that are typical for battery-like materials, contribute predominantly to the high electrode capacity of 257C g(-1) (at 0.1 A g(-1)). By combining nickel oxide with a capacitive material such as activated carbon within the two-electrode symmetric cell, systems with increased charge-storage capabilities have been obtained. The fact, that the voltage window of nickel oxide-based cell has been broadened positively from 0.6 V to 1 V upon introduction of activated carbon, has also resulted in the increase of the cell's energy and power densities as well.
|
|
| 6. |
- Delices, Annette, et al.
(författare)
-
Experimental and theoretical study of organic sensitizers for solid-state dye-sensitized solar cells (s-DSSCs)
- 2022
-
Ingår i: Journal of Photochemistry and Photobiology A. - : Elsevier. - 1010-6030 .- 1873-2666. ; 428
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of a series of triarylamine based D-pi-A organic dyes, namely RK1, BA504, BA741 and the simple L1 reference dye on solid-state dye sensitized solar cells (s-DSSCs) performances was studied. The solid hole transporting material (HTM) was obtained by in-situ photoelectrochemical polymerization (in-situ PEP) process applied in two different media (water and acetonitrile) to produce the poly-3,4 ethylenedioxythiophene (PEDOT) conducting polymer (CP). A joint experimental and theoretical (density functional theory and time-dependent density functional theory) study is conducted to correlate the dye molecular structure containing different donor, pi-bridge or acceptor with several physicochemical characteristics such as optical (absorption and emission), electronic and redox properties of dyes in organic and aqueous medium; in-situ PEP process and charge transfer kinetics at the DSSC interfaces (Dye/TiO2 and Dye/HTM) through the alignment of the different energy levels of the dyes and electrodes. These properties are considered since they govern the performance of s-DSSCs denoted by the short-circuit current (J(sc)), open circuit cell potential (V-oc) and fill factor (FF). Among the four studied dyes, the s-DSSCs based on RK1, shows the best power conversion efficiency of 1.75% resulting from highest FF (0.57), V-oc (550 mV) and J(sc) (5.6 mA/cm(2)). The large differences in experimental photovoltaic performances of the obtained s-DSSCs have been well outlined and provide the guidelines for future development of more efficient solar-cell sensitizers.
|
|
| 7. |
- Delices, Annette, et al.
(författare)
-
New covalently bonded dye/hole transporting material for better charge transfer in solid-state dye-sensitized solar cells
- 2018
-
Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 269, s. 163-171
-
Tidskriftsartikel (refereegranskat)abstract
- A novel metal-free organic dye based on triarylamine functionalized by a carbazole unit is synthesized and used in solid state dye sensitized solar cells (sDSC). The carbazole is co-polymerized with bis-EDOT by in-situ photo-electrochemical polymerization leading to a hole transporting polymer material covalently bonded to the light active centre. These first photovoltaic performances results are promising in sDSCs applications.
|
|
| 8. |
- Ellis, Hanna, et al.
(författare)
-
PEDOT counter electrodes for dye-sensitized solar cells prepared by aqueous micellar electrodeposition
- 2013
-
Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 107, s. 45-51
-
Tidskriftsartikel (refereegranskat)abstract
- Electropolymerization of 3,4-ethylenedioxythiophene (EDOT) was performed in an aqueous micellar solution onto conducting glass and conducting flexible plastic substrates using a simple, scalable process. The background electrolyte in the process consisted merely of a micellar aqueous sodium dodecyl sulfate (SDS) solution. Electrodeposition of poly(3,4-ethylenedioxythiophene) (PEDOT) was conducted at constant current, resulting in homogeneous films, even on large sized conducting glass and plastic substrates (9 cm x 9 cm). The use of water as electrolyte, application on large substrates and applicability on flexible plastic substrates demonstrates the feasibility of this method for upscaling and use in industrial fabrication of DSCs. DSCs were assembled using three different PEDOT thicknesses on conducting glass as counter electrodes and a comparison was made with thermally platinized conducting glass counter electrodes. In cobalt tris(bipyridine)-based electrolyte, the catalytic performance of the PEDOT counter electrodes was significantly higher than that of platinized counter electrodes. DSCs with PEDOT counter electrodes gave higher efficiencies due to higher fill factors and a lower charge transfer resistance. The low charge transfer resistance and good catalytic performance of the PEDOT counter electrodes can be related to its mesoporous morphology resembling crumpled sheets of paper.
|
|
| 9. |
- Liu, Peng, et al.
(författare)
-
The combination of a new organic D-pi-A dye with different organic hole-transport materials for efficient solid-state dye-sensitized solar cells
- 2015
-
Ingår i: Journal of Materials Chemistry A. - : RSC Publishing. - 2050-7488 .- 2050-7496. ; 3:8, s. 4420-4427
-
Tidskriftsartikel (refereegranskat)abstract
- A new organic donor-pi-acceptor sensitizer MKA253 has been applied for highly efficient solid-state dye-sensitized solar cells (ssDSSCs). Using 2,2',7,7'-tetrakis(N,N-di-pi-methoxyphenyl-amine) 9,9'-spirobifluorene (Spiro-OMeTAD) as the hole transport material (HTM), an excellent power conversion efficiency of 6.1% was recorded together with a high short-circuit current of 12.4 mA cm(-2) under standard AM 1.5G illumination (100 mW cm(-2)). Different combinations of dyes and HTMs have also been investigated in the ssDSSC device. The results showed that small molecule HTM based devices suffer from comparably high electron recombination losses, thus causing low open-circuit voltage. In addition, photo-induced absorption (PIA) spectroscopy showed that the small-molecule HTMs lead to more efficient dye regeneration in comparison with Spiro-OMeTAD, despite a lower thermodynamic driving force. The results of this study also show that optimized energy levels for the dye-HTMs could be a vital factor for highly efficient ssDSSCs.
|
|
| 10. |
- Morgante, Michele, et al.
(författare)
-
Microbial bioelectrochemical cells for hydrogen generation based on irradiated semiconductor photoelectrodes
- 2021
-
Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 2515-7655. ; 3:3
-
Forskningsöversikt (refereegranskat)abstract
- In recent years, one of the most important challenges of the 21st century is to satisfy the ever-increasing world's energy demand. Many efforts are being undertaken to find alternative renewable energy sources, which ideally should outcompete fossil fuel use in all its aspects. In this respect, photo-assisted microbial bioelectrochemical cells (MBECs) in which the reduction of water to hydrogen takes place have been of considerable interest in recent years. Two categories of such systems have been investigated: MBECs with a semiconductor photocathode or photoanode, and hybrid systems, in which an MBEC cell with dark electrodes is coupled to an electrochemical photovoltaic cell. A common denominator of all these systems is the need of microorganisms at the anode, the action of which results in the generation of an electron flow by organic matter oxidation. The aim of this review is to describe the general working principles, with respect to both biochemical and electrochemical aspects, and the performance of various categories of hydrogen-generating photo-assisted MBECs.
|
|
| 11. |
- Nonomura, Kazuteru, et al.
(författare)
-
Blocking the Charge Recombination with Diiodide Radicals by TiO2 Compact Layer in Dye-Sensitized Solar Cells
- 2019
-
Ingår i: Journal of the Electrochemical Society. - : ELECTROCHEMICAL SOC INC. - 0013-4651 .- 1945-7111. ; 166:9, s. B3203-B3208
-
Tidskriftsartikel (refereegranskat)abstract
- The addition of a compact titanium dioxide (TiO2) layer between the fluorine-doped tin oxide (FTO) coated glass substrate and the mesoporous TiO2 layer in the dye-sensitized solar cell (DSC) based on the iodide/triiodide redox couple (I-/I-3(-)) is known to improve its current-voltage characteristics. The compact layer decreases the recombination of electrons extracted through the FTO layer with I-3(-) around the maximum power point. Furthermore, the short-circuit photocurrent was improved, which previously has been attributed to the improved light transmittance and/or better contact between TiO2 and FTO. Here, we demonstrate that the compact TiO2 layer has another beneficial effect: it blocks the reaction between charge carriers in the FTO and photogenerated diiodide radical species (I-2(-center dot)). Using photomodulated voltammetry, it is demonstrated that the cathodic photocurrent found at bare FTO electrodes is blocked by the addition of a compact TiO2 layer, while the anodic photocurrent due to reaction with I-2(-center dot) is maintained.
|
|
| 12. |
- Park, Byung-wook, et al.
(författare)
-
Neutral, Polaron, and Bipolaron States in PEDOT Prepared by Photoelectrochernical Polymerization and the Effect on Charge Generation Mechanism in the Solid-State Dye-Sensitized Solar Cell
- 2013
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:44, s. 22484-22491
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate dye-sensitized solar cells (DSSCs) based on PEDOT as hole conductor and prepared by photoelectrochemical polymer deposition at different light intensities. We specifically investigate the effect of light intensity on the PEDOT polymer and in turn the efficiency of the solar cells. We find that the PEDOT prepared by this method is largely oxidized and contains significant amounts of polarons and bipolarons and only a small fraction of neutral PEDOT. Photoelectrochemical polymer deposition under low light intensity leads to a particularly low fraction of neutral PEDOT and a high fraction of bipolarons as measured in the UV-vis spectra. The solar cells based on PEDOT as a hole conductor prepared under these conditions are the most efficient with a higher power conversion efficiency, which can be explained by a longer electron lifetime, faster charge transport, and higher transparency of the PEDOT. Interestingly, we conclude that in this type of solid-state DSSCs the mechanism of dye regeneration occurs from PEDOT polarons that then form bipolarons, which is different from the mechanism of dye regeneration proposed in standard solid-state DSSCs.
|
|
| 13. |
- Ren, Yameng, et al.
(författare)
-
Hydroxamic acid pre-adsorption raises the efficiency of cosensitized solar cells
- 2023
-
Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 613:7942, s. 60-65
-
Tidskriftsartikel (refereegranskat)abstract
- Dye-sensitized solar cells (DSCs) convert light into electricity by using photosensitizers adsorbed on the surface of nanocrystalline mesoporous titanium dioxide (TiO2) films along with electrolytes or solid charge-transport materials(1-3). They possess many features including transparency, multicolour and low-cost fabrication, and are being deployed in glass facades, skylights and greenhouses(4). Recent development of sensitizers(5-10), redox mediators(11-13) and device structures(14) has improved the performance of DSCs, particularly under ambient light conditions(14-17). To further enhance their efficiency, it is pivotal to control the assembly of dye molecules on the surface of TiO2 to favour charge generation. Here we report a route of pre-adsorbing a monolayer of a hydroxamic acid derivative on the surface of TiO2 to improve the dye molecular packing and photovoltaic performance of two newly designed co-adsorbed sensitizers that harvest light quantitatively across the entire visible domain. The best performing cosensitized solar cells exhibited a power conversion efficiency of 15.2% (which has been independently confirmed) under a standard air mass of 1.5 global simulated sunlight, and showed long-term operational stability (500 h). Devices with a larger active area of 2.8 cm(2) exhibited a power conversion efficiency of 28.4% to 30.2% over a wide range of ambient light intensities, along with high stability. Our findings pave the way for facile access to high-performance DSCs and offer promising prospects for applications as power supplies and battery replacements for low-power electronic devices(18-20) that use ambient light as their energy source.
|
|
| 14. |
- Saygili, Yasemin, et al.
(författare)
-
Copper Bipyridyl Redox Mediators for Dye-Sensitized Solar Cells with High Photovoltage
- 2016
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 138:45, s. 15087-15096
-
Tidskriftsartikel (refereegranskat)abstract
- Redox mediators play a major role determining the photocurrent and the photovoltage in dye-sensitized solar cells (DSCs). To maintain the photocurrent, the reduction of oxidized dye by the redox mediator should be significantly faster than the electron back transfer between TiO2 and the oxidized dye. The driving force for dye regeneration with the redox mediator should be sufficiently low to provide high photovoltages. With the introduction of our new copper complexes as promising redox mediators in DSCs both criteria are satisfied to enhance power conversion efficiencies. In this study, two copper bipyridyl complexes, Cu-(II/I)(dmby)(2)TFSI2/1 (0.97 V vs SHE, dmby = 6,6'-dimethyl-2,2'-bipyridine) and Cu-(II/I)(tmby)(2)TFSI2/1 (0.87 V vs SHE, tmby = 4,4',6,6'-tetramethyl-2,2'-bipyridine), are presented as new redox couples for DSCs. They are compared to previously reported Cu-(II/I)(dmp)(2)TFSI2/1 (0.93 V vs SHE, dmp = bis(2,9-dimethyl-1,10-phenanthroline). Due to the small reorganization energy between Cu(I) and Cu(II) species, these copper complexes can sufficiently regenerate the oxidized dye molecules with close to unity yield at driving force potentials as low as 0.1 V. The high photovoltages of over 1.0 V were achieved by the series of copper complex based redox mediators without compromising photocurrent densities. Despite the small driving forces for dye regeneration, fast and efficient dye regeneration (2-3 mu s) was observed for both complexes. As another advantage, the electron back transfer (recombination) rates were slower with Cu-(II/I)(tmby)(2)TFSI2/1 as evidenced by longer lifetimes. The solar-to-electrical power conversion efficiencies for [Cu(tmby)(2)](2+/1+), [Cu(dmby)(2)](2+/1+) , and [Cu(dmp)(2)](2+/1+) based electrolytes were 10.3%, 10.0%, and 10.3%, respectively, using the organic Y123 dye under 1000 W m(-2) AM1.5G illumination. The high photovoltaic performance of Cu-based redox mediators underlines the significant potential of the new redox mediators and points to a new research and development direction for DSCs.
|
|
| 15. |
- Skunik-Nuckowska, Magdalena, et al.
(författare)
-
Integration of solid-state dye-sensitized solar cell with metal oxide charge storage material into photoelectrochemical capacitor
- 2013
-
Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 234, s. 91-99
-
Tidskriftsartikel (refereegranskat)abstract
- A solid-state photo-rechargeable capacitor (photocapacitor) is obtained here by coupling a dye-sensitized solar cell and a ruthenium oxide based electrochemical capacitor. This integrated system permits direct storage of energy generated by sunlight within a single optoelectronic micro-electrochemical device. It utilizes three planar electrodes arranged sequentially to include a polymer hole conductor (poly-(3-hexylthiophene-2,5-diyl)), between the titanium oxide photoanode modified with dye (E)-3-(5-(4-(Bis(20,40-dibutoxybiphenyl-4-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid (D35) and the intermediate silver electrode as well as two hydrous ruthenium oxide layers (separated by protonically conducting Nafion (TM) membrane) between the intermediate (silver) and the external (counter) electrode. Upon integration of the capacitor and dye-sensitized solar cell into a single photocapacitor hybrid device, the following parameters were obtained under simulated 100 mW cm(-2) solar illumination: specific capacitance, 407 F g(-1) (3.26 F cm(-2)); energy and power densities, 0.17 mWh cm(-2) and 0.34 mW cm(-2) and coulombic efficiency, 88%. These data together with results of experiments performed at different light intensities (10-100 mW cm(-2)) are consistent with very good performance of the optoelectronic device under various light conditions.
|
|
| 16. |
- Vlachopoulos, Nick, et al.
(författare)
-
Dye-sensitized Solar Cells : New Approaches with Organic Solid-state Hole Conductors
- 2015
-
Ingår i: CHIMIA. - : Swiss Chemical Society. - 0009-4293 .- 2673-2424. ; 69:1-2, s. 41-51
-
Tidskriftsartikel (refereegranskat)abstract
- Solid-state dye-sensitized solar cells (sDSCs) in which a solid organic charge-transfer medium, or hole conductor (HC), is interposed between a dye-coated mesoporous oxide electrode and a conductive counter electrode, have attracted considerable interest as viable alternatives to the more ubiquitous mediator-electrolyte DSC. Of particular importance to efficient operation are, in addition to the useful processes contributing to current generation (light harvesting, electron injection and current collection), the recombinative deleterious processes. The organic HCs are highly reactive toward electrons in the oxide or the conducting glass support, therefore necessitating the inclusion of a carefully prepared thin blocking oxide underlayer support as well as the molecular design of special dark current-suppressing dyes. Initially (mid-1990s) sDSCs with organic small molecular weight hole conductors have undergone systematic investigation. At the same time the first tests of sDSCs with conducting polymer hole conductors were published, with subsequent emphasis on the in situ generation of the HC inside the pores. For both types of devices a light-to-electricity conversion efficiency, in the 5-10% range for several dye-HC combinations, approaches that of the most efficient DSCs with non-volatile liquid electrolytes, thereby encouraging further efforts for obtaining stable, efficient and inexpensive sDSCs.
|
|
| 17. |
- Vlachopoulos, Nick, et al.
(författare)
-
Electrochemical aspects of display technology based on nanostructured titanium dioxide with attached viologen chromophores
- 2008
-
Ingår i: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 53:11, s. 4065-4071
-
Tidskriftsartikel (refereegranskat)abstract
- Progress in recent years in the field of electrochromic displays based on viologen modified high-surface area TiO2 electrodes (Vio(2+)/TiO2) has moved the technology towards commercialisation. Viologen molecules (Vio(2+)), derivatised with phosphonic acid attachment groups can be chemisorbed on nanostructured TiO2 layers of thickness 2-10 mu m. Characterisation by cyclic voltammetry, spectroelectrochemistry and impedance spectroscopy demonstrates that colourless Vio(2+)/TiO2 is reversibly reduced to the strongly coloured cation radical species Vio(+center dot)/TiO2. This system can constitute the working electrode of an electrochromic display with a capacitive doped SnO2 electrode as counter electrode, the latter coated by an electrochemically inert white fight-reflecting layer. Such a device is stable upon repeated colouration-bleaching cycles with a bleached-to-coloured state contrast ratio exceeding 5. Multicolour displays can be achieved by patterning different electrochromophores onto different areas of one working electrode. (C) 2007 Elsevier Ltd. All rights reserved.
|
|
| 18. |
- Vlachopoulos, Nick, et al.
(författare)
-
New approaches in component design for dye-sensitized solar cells
- 2021
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 5:2, s. 367-383
-
Tidskriftsartikel (refereegranskat)abstract
- The present perspective presents a number of issues related to the current direction of DSSC research, with emphasis on the transition from iodide-containing electrolyte to charge-transport media (CTMs), electrolytes or solid-state conductors based on inorganic coordination complexes, aiming to attain a better light-to-electricity conversion efficiency, associated with larger photovoltage, and long-term stability. Such a change necessitates the concomitant introduction of novel dyes and counter electrodes. The first part of the perspective introduces an overview of the DSSC field and a number of considerations related to the transition from the triiodide/iodide-based CTM to CTMs based on alternative systems. Subsequently, the recent developments of CTM based on Cu coordination complexes are discussed, from the inorganic physical chemistry point of view, including some highlights about novel dyes associated to these CTMs. Finally, several preparation methods and applications of different types of novel carbonaceous counter electrode substrates, related to the application of the aforementioned novel CTMs, are presented.
|
|
| 19. |
- Vlachopoulos, Nick, et al.
(författare)
-
Solid-state dye-sensitized solar cells using polymeric hole conductors
- 2021
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:62, s. 39570-39581
-
Forskningsöversikt (refereegranskat)abstract
- The present review presents the application of electronically conducting polymers (conducting polymers) as hole conductors in solid-state dye solar cells (S-DSSCs). At first, the basic principles of dye solar cell operation are presented. The next section deals with the principles of electrochemical polymerisation and its photoelectrochemical variety, the latter being an important, frequently-used technique for generating conducting polymers and hole conductors in DSSCs. Finally, two varieties of S-DSSC configurations, those of dry S-DSSC and of S-DSSCs incorporating a liquid electrolyte, are discussed.
|
|
| 20. |
- Xu, Bo, et al.
(författare)
-
Carbazole-Based Hole-Transport Materials for Efficient Solid-State Dye-Sensitized Solar Cells and Perovskite Solar Cells
- 2014
-
Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 26:38, s. 6629-6634
-
Tidskriftsartikel (refereegranskat)abstract
- (Graph Presented) Two carbazole-based small molecule hole-transport materials (HTMs) are synthesized and investigated in solid-state dye-sensitized solar cells (ssDSCs) and perovskite solar cells (PSCs). The HTM X51-based devices exhibit high power conversion efficiencies (PCEs) of 6.0% and 9.8% in ssDSCs and PSCs, respectively. These results are superior or comparable to those of 5.5% and 10.2%, respectively, obtained for the analogous cells using the state-of-the-art HTM Spiro-OMeTAD.
|
|
| 21. |
- Xu, Bo, et al.
(författare)
-
Integrated Design of Organic Hole Transport Materials for Efficient Solid-State Dye-Sensitized Solar Cells
- 2015
-
Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 5:3
-
Tidskriftsartikel (refereegranskat)abstract
- A series of triphenylamine-based small molecule organic hole transport materials (HTMs) with low crystallinity and high hole mobility are systematically investigated in solid-state dye-sensitized solar cells (ssDSCs). By using the organic dye LEG4 as a photosensitizer, devices with X3 and X35 as the HTMs exhibit desirable power conversion efficiencies (PCEs) of 5.8% and 5.5%, respectively. These values are slightly higher than the PCE of 5.4% obtained by using the state-of-the-art HTM Spiro-OMeTAD. Meanwhile, transient photovoltage decay measurement is used to gain insight into the complex influences of the HTMs on the performance of devices. The results demonstrate that smaller HTMs induce faster electron recombination in the devices and suggest that the size of a HTM plays a crucial role in device performance, which is reported for the first time.
|
|
| 22. |
- Yang, Lei, et al.
(författare)
-
New Approach for Preparation of Efficient Solid-State Dye-Sensitized Solar Cells by Photoelectrochemical Polymerization in Aqueous Micellar Solution
- 2013
-
Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 4:23, s. 4026-4031
-
Tidskriftsartikel (refereegranskat)abstract
- Hereby, we present a new, cost-effective, and environmentally friendly method of preparing an efficient solid-state dye-sensitized solar cell (sDSC) using a PEDOT conducting polymer as the hole conductor and a recently developed organic sensitizer. PEDOT is generated and deposited on the dye-sensitized TiO2 electrode by in situ photoelectropolymerization of bis-EDOT in aqueous micellar solution. The advantages of this approach are the use of water as the solvent and the obtainment of a sDSC simply by adding a silver layer on the as-obtained polymer film deposited on dye/TiO2 without the need for electrolytic solution. The sDSC containing the film prepared as above is compared to those where the organic dye is used to generate the same polymer film but in organic solvent. The energy conversion efficiency values of the two cells appear comparable, 4.8% for sDSC prepared in the aqueous-phase polymerized PEDOT and 6% for the sDSC prepared with in organic-phase polymerized PEDOT.
|
|
| 23. |
- Yang, Wenxing, et al.
(författare)
-
Efficient dye regeneration at low driving force achieved in triphenylamine dye LEG4 and TEMPO redox mediator based dye-sensitized solar cells
- 2015
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 17:24, s. 15868-15875
-
Tidskriftsartikel (refereegranskat)abstract
- Minimizing the driving force required for the regeneration of oxidized dyes using redox mediators in an electrolyte is essential to further improve the open-circuit voltage and efficiency of dye-sensitized solar cells (DSSCs). Appropriate combinations of redox mediators and dye molecules should be explored to achieve this goal. Herein, we present a triphenylamine dye, LEG4, in combination with a TEMPO-based electrolyte in acetonitrile (E-0 = 0.89 V vs. NHE), reaching an efficiency of up to 5.4% under one sun illumination and 40% performance improvement compared to the previously and widely used indoline dye D149. The origin of this improvement was found to be the increased dye regeneration efficiency of LEG4 using the TEMPO redox mediator, which regenerated more than 80% of the oxidized dye with a driving force of only similar to 0.2 eV. Detailed mechanistic studies further revealed that in addition to electron recombination to oxidized dyes, recombination of electrons from the conducting substrate and the mesoporous TiO2 film to the TEMPO+ redox species in the electrolyte accounts for the reduced short circuit current, compared to the state-of-the-art cobalt tris(bipyridine) electrolyte system. The diffusion length of the TEMPO-electrolyte based DSSCs was determined to be similar to 0.5 mu m, which is smaller than the similar to 2.8 mu m found for cobalt-electrolyte based DSSCs. These results show the advantages of using LEG4 as a sensitizer, compared to previously record indoline dyes, in combination with a TEMPO-based electrolyte. The low driving force for efficient dye regeneration presented by these results shows the potential to further improve the power conversion efficiency (PCE) of DSSCs by utilizing redox couples and dyes with a minimal need of driving force for high regeneration yields.
|
|
| 24. |
- Yang, Wenxing, 1988-, et al.
(författare)
-
Impact of Local Electric Fields on Charge-Transfer Processes at the TiO2/Dye/Electrolyte Interface
- 2017
-
Ingår i: ACS Energy Letter. - : American Chemical Society (ACS). - 2380-8195. ; 2:1, s. 161-167
-
Tidskriftsartikel (refereegranskat)abstract
- Photoinduced electron -transfer processes at the TiO2/ dye/electrolyte interface are vital for various emerging technologies. Here, the impact of the local electric field at this interface on the charge -transfer processes was investigated in two aspects: (a) charge recombination between the electrons accumulated within TiO2 and the photoxidized dye and (b) regeneration of the dyes by the cobalt bipyridyl redox mediators. The amplitude of the local electric field was changed by use of different cations in the electrolytic environment, in the order E-Ca(2+) > E-Mg(2+)> E-Na(+) > E-u(+) characterized by the transient absorption spectroscopy. For the charge recombination process, the kinetic time constant showed a remarkable linear correlation with the relative electric field strength, while for the regeneration process, no evident dependence was observed. These results collectively suggest the spatial confinement of the effects of the local electric field on the interfacial electron -transfer processes.
|
|
| 25. |
- Yang, Wenxing, et al.
(författare)
-
Studies on the Interfacial Electric Field and Stark Effect at the TiO2/Dye/Electrolyte Interface
- 2016
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:39, s. 22215-22224
-
Tidskriftsartikel (refereegranskat)abstract
- Interfaces of dye-sensitized TiO2 nanoparticles with electrolytes or hole conductors have been widely applied in photoelectrochemical cells. However, the fundamental understanding of their properties and function is still poor. Herein, we demonstrate that the spectral changes that occur in the-visible spectrum of dye-sensitized TiO2 films upon (a) Li+ titration, (b) potentiostatic electron accumulation in mesoporous TiO2, and (c) photoinduced electron injection into TiO2 can be explained by the Stark effect, which can then be used to characterize the change in the local electric field at the TiO2/dye/electrolyte interface. A quantitative analysis of the Stark effect indicates that the compact (Helmholtz) layer capacitance at the TiO2/dye/electrolyte interface strongly affects the strength of the local electric field. Systematic studies show that the Helmholtz layer capacitance depends strongly on the Li+ concentration and surface dye coverage but is independent of the concentrations of other electrolytic species and the light intensity. These results illustrate the potential of Stark spectroscopy for the in situ study of the TiO2/dye/electrolyte interfaces and provide substantial new insights into these widely applied interfaces related to photoelectrochemistry and other research fields.
|
|
| 26. |
- Yu, Ze, et al.
(författare)
-
Incompletely solvated ionic liquid mixtures as electrolyte solvents for highly stable dye-sensitized solar cells
- 2013
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 3:6, s. 1896-1901
-
Tidskriftsartikel (refereegranskat)abstract
- Ionic liquids have been intensively investigated as alternative stable electrolyte solvents for dye-sensitized solar cells (DSCs). A highest overall conversion efficiency of over 8% has been achieved using a ionic-liquid-based electrolyte in combination with an iodide/triiodide redox couple. However, the relatively high viscosities of ionic liquids require higher iodine concentration in the electrolyte due to mass-transport limitations of the triiodide ions. The higher iodine concentration significantly reduces the photovoltaic performance, which normally are lower than those using organic solvent-based electrolytes. Here, the concept of incompletely solvated ionic liquid mixtures (ISILMs) is introduced and represents a conceptually new type of electrolyte solvent for DSCs. It is found that the photovoltaic performance of ISILM-based electrolytes can rival that of organic solvent-based electrolytes. Furthermore, the vapor pressures of ISILMs are found to be considerably lower than that for pure organic solvents. Stability tests show that ISILM-based electrolytes provide highly stable DSCs under light soaking conditions. Thus, ISILM-based electrolytes offer a new platform to develop more efficient and stable DSC devices of relevance to future large-scale applications.
|
|
| 27. |
- Yu, Zu, et al.
(författare)
-
Incompletely Solvated Ionic Liquids as Electrolyte Solvents for Highly Stable Dye-Sensitized Solar Cells
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Ionic liquids have been intensively investigated as alternative stable electrolyte solvents for dye-sensitized solar cells (DSCs). A highest overall conversion efficiency of over 8% has been achieved using ionic-liquid-based electrolyte in combination with an iodide/triiodide redox couple. However, the relatively high viscosities of ionic liquids require higher iodine concentration in the electrolyte due to mass-transport limitations of the triiodide ions. The higher iodine concentration significantly reduces the photovoltaic performance, which normally are lower than those using organic solvent-based electrolytes. Here, the concept of incompletely solvated ionic liquids (ISILs) is introduced and represents a conceptually new type of electrolyte solvents for DSCs. It is found that the photovoltaic performance of ISIL-based electrolytes can rival that of organic solvent-based electrolytes. Furthermore, the vapor pressures of ISILs are found be considerably lower than that for pure organic solvent. Stability tests show that ISIL-based electrolytes provide highly stable DSCs under light-soaking conditions. Thus, ISIL-based electrolytes offer a new platform to develop more efficient and stable DSC devices of relevance to future large-scale applications.
|
|
| 28. |
- Yu, Ze, et al.
(författare)
-
Liquid electrolytes for dye-sensitized solar cells
- 2011
-
Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 40:40, s. 10289-10303
-
Tidskriftsartikel (refereegranskat)abstract
- The present review offers a survey of liquid electrolytes used in dye-sensitized solar cells from the beginning of photoelectrochemical cell research. It handles both the solvents employed, and the prerequisites identified for an ideal liquid solvent, as well as the various effects of electrolyte solutes in terms of redox systems and additives. The conclusions of the present review call for more detailed molecular insight into the electrolyte-electrode interface reactions and structures.
|
|
| 29. |
|
|
| 30. |
- Zhang, Jinbao, et al.
(författare)
-
Efficient Blue-Colored Solid-State Dye-Sensitized Solar Cells : Enhanced Charge Collection by Using an in Situ Photoelectrochemically Generated Conducting Polymer Hole Conductor.
- 2016
-
Ingår i: ChemPhysChem. - : Wiley. - 1439-4235 .- 1439-7641. ; 17:10, s. 1441-1445
-
Tidskriftsartikel (refereegranskat)abstract
- A high power conversion efficiency (PCE) of 5.5 % was achieved by efficiently incorporating a diketopyrrolopyrrole-based dye with a conducting polymer poly(3,4-ethylenediothiophene) (PEDOT) hole-transporting material (HTM) that was formed in situ, compared with a PCE of 2.9 % for small molecular spiro-OMeTAD-based solid-state dye solar cells (sDSCs). The high PCE for PEDOT-based sDSCs is mainly attributed to the significantly enhanced charge-collection efficiency, as a result of the three-order-of-magnitude higher hole conductivity (0.53 S cm(-1) ) compared with that of the widely used low molecular weight HTM spiro-OMeTAD (3.5×10(-4) S cm(-1) ).
|
|
| 31. |
- Zhang, Jinbao, et al.
(författare)
-
Efficient solid-state dye sensitized solar cells : The influence of dye molecular structures for the in-situ photoelectrochemically polymerized PEDOT as hole transporting material
- 2016
-
Ingår i: NANO ENERGY. - : Elsevier BV. - 2211-2855. ; 19, s. 455-470
-
Tidskriftsartikel (refereegranskat)abstract
- Solid-state dye sensitized solar cells (sDSCs) with organic small molecule hole transporting materials (HTMs) have limited efficiencies due to the incomplete pore filling of the HTMs in the thick mesoporous electrodes and the low hole conductivity of HTMs. Hereby, highly efficient sDSCs with power conversion efficiency of 7.11% and record photocurrent of 13.4 mA cm-2 are reported, prepared by effectively incorporating in-situ photoelectrochemically polymerized PEDOT as HTM in combination with a multifunctional organic, metal-free dye. In order to fundamentally understand how the dye molecules affect the photoelectrochemical polymerization (PEP), the properties of the generated PEDOT and the photovoltaic performance, sDSCs based on a series of dyes are systematically investigated. Detailed comparative studies reveal that the difference between the dye redox potential and monomer onset oxidation potential plays a crucial role in the PEP kinetics and the doping density of PEDOT HTM. The structure of the dyes, functioning as an electron blocking layer, affects the charge recombination at the TiO2/dye/PEDOT interface. The analysis shows that a donor-n-acceptor dye with well-tuned energy levels and bulky structure results in an in-situ electrochemically doped PEDOT HTM with a high hole conductivity (2.0 S cm(-1)) in sDSCs, leading to efficient dye regeneration and photocharge collection. It is hoped that this work will further encourage research on the future design of new dye molecules for an efficient PEP in order to further enhance the photovoltaic performance of solid-state dye sensitized solar cells.
|
|
| 32. |
- Zhang, Jinbao, 1987-, et al.
(författare)
-
Electrochemically polymerized poly (3, 4-phenylenedioxythiophene) as efficient and transparent counter electrode for dye sensitized solar cells
- 2019
-
Ingår i: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 300, s. 482-488
-
Tidskriftsartikel (refereegranskat)abstract
- A new conducting polymer poly (3, 4-phenylenedioxythiophene) is synthesized by the electrochemical polymerization technique with different solvents. We find that solvents used in electrochemical polymerization play important roles for the catalytic activity and morphology of the formed conducting polymers. The obtained poly (3, 4-phenylenedioxythiophene) is for the first time employed as counter electrode electrocatalyst in dye sensitized solar cells with cobalt-based electrolytes. We demonstrate that a polymer prepared from a mixed acetonitrile-dichloromethane solvent exhibit higher catalytic activity for redox reactions, as compared to that from a single solvent, dichloromethane. The devices based on this mixed solvent-based polymer from a mixed solvents show a high power conversion efficiency of 5.97%. An additional advantageous feature of the electrochemically polymerized poly (3, 4-phenylenedioxythiophene) for solar cell applications is the high transparency in the visible and nearinfrared region. We also investigate the beneficial effect of the poly (3, 4-phenylenedioxythiophene) layer thickness on device performance, and concluded that the series resistance and charge transfer resistance are greatly influenced by the thickness of polymer, as evidenced by electrochemical impedance spectroscopy measurements. The optimal thickness for poly (3, 4-phenylenedioxythiophene) is about 100 nm. Furthermore, the high catalytic activity and transparency of the new conducting polymer as counter electrode shows great promise for other optoelectronic applications.
|
|
| 33. |
- Zhang, Jinbao, et al.
(författare)
-
Incorporation of Counter Ions in Organic Molecules : New Strategy in Developing Dopant-Free Hole Transport Materials for Efficient Mixed-Ion Perovskite Solar Cells
- 2017
-
Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 7:14
-
Tidskriftsartikel (refereegranskat)abstract
- Hole transport matertial (HTM) as charge selective layer in perovskite solar cells (PSCs) plays an important role in achieving high power conversion efficiency (PCE). It is known that the dopants and additives are necessary in the HTM in order to improve the hole conductivity of the HTM as well as to obtain high efficiency in PSCs, but the additives can potentially induce device instability and poor device reproducibility. In this work a new strategy to design dopant-free HTMs has been presented by modifying the HTM to include charged moieties which are accompanied with counter ions. The device based on this ionic HTM X44 dos not need any additional doping and the device shows an impressive PCE of 16.2%. Detailed characterization suggests that the incorporated counter ions in X44 can significantly affect the hole conductivity and the homogeneity of the formed HTM thin film. The superior photovoltaic performance for X44 is attributed to both efficient hole transport and effective interfacial hole transfer in the solar cell device. This work provides important insights as regards the future design of new and efficient dopant free HTMs for photovotaics or other optoelectronic applications.
|
|
| 34. |
- Zhang, Jinbao, et al.
(författare)
-
Matrix-Assisted Laser Desorption/Ionization Mass Spectrometric Analysis of Poly(3,4-ethylenedioxythiophene) in Solid-State Dye-Sensitized Solar Cells : Comparison of In Situ Photoelectrochemical Polymerization in Aqueous Micellar and Organic Media
- 2015
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 87:7, s. 3942-3948
-
Tidskriftsartikel (refereegranskat)abstract
- Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.
|
|
| 35. |
- Zhang, Jinbao, 1987-
(författare)
-
Organic Hole Transport Materials for Solid-State Dye-Sensitized and Perovskite Solar Cells
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solid-state dye-sensitized solar cells (ssDSSCs) and recently developed perovskite solar cells (PSCs) have attracted a great attention in the scientific field of photovoltaics due to their low cost, absence of solvent, simple fabrication and promising power conversion efficiency (PCE). In these types of solar cell, the dye molecule or the perovskite can harvest the light on the basis of electron excitation. Afterwards, the electron and hole are collected at the charge transport materials.Photoelectrochemical polymerization (PEP) is employed in this thesis to synthesize conducting polymer hole transport materials (HTMs) for ssDSSCs. We have for the first time developed aqueous PEP in comparison with the conventional organic PEP with acetonitrile as solvent. This water-based PEP could potentially provide a low-cost, environmental-friendly method for efficient deposition of polymer HTM for ssDSSCs. In addition, new and simple precursors have been tested with PEP method. The effects of dye molecules on the PEP were also systematically studied, and we found that (a) the bulky structure of dye is of key importance for blocking the interfacial charge recombination; and (b) the matching of the energy levels between the dye and the precursor plays a key role in determining the kinetics of the PEP process.In PSCs, the HTM layer is crucial for efficient charge collection and its long term stability. We have studied different series of new molecular HTMs in order to understand fundamentally the influence of alkyl chains, molecular energy levels, and molecular geometry of the HTM on the photovoltaic performance. We have identified several important factors of the HTMs for efficient PSCs, including high uniformity of the HTM capping layer, perovskite-HTM energy level matching, good HTM solubility, and high conductivity. These factors affect interfacial hole injection, hole transport, and charge recombination in PSCs. By systematical optimization, a promising PCE of 19.8% has been achieved by employing a new HTM H11. We believe that this work could provide important guidance for the future development of new and efficient HTMs for PSCs.
|
|
| 36. |
- Zhang, Jinbao, et al.
(författare)
-
Photoelectrochemical Polymerization of EDOT for Solid State Dye Sensitized Solar Cells : Role of Dye and Solvent
- 2015
-
Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 179, s. 220-227
-
Tidskriftsartikel (refereegranskat)abstract
- The aromatic-unit, commercially available, and cost-effective precursor 3, 4-ethylenedioxythiophene (EDOT), was employed instead of bis-EDOT to generate by in-situ photoelectrochemical polymerization (PEP) a conducting polymer-type hole conductor poly (3, 4-ethylenedioxythiophene) (PEDOT) for dye sensitized solar cell (DSC) devices. In order to conduct efficiently the PEP of EDOT, two electrolytic media, aqueous micellar and organic, and two Donor-pi-Acceptor sensitizers, were investigated. By using the electrolytic aqueous micellar medium, the PEP was efficient due to the low oxidation potential of the precursor in water. A DSC device based on PEDOT generated from aqueous PEP showed an energy conversion efficiency (eta) of 3.0% under 100 mWcm (2), higher by two orders of magnitude than that of a DSC device based on PEDOT from organic PEP (eta = 0.04%). The comparison of the properties of the as-obtained PEDOT polymers from aqueous and organic PEP by UV-VIS-NIR measurements shows the formation of PEDOT at a highly doped state from aqueous PEP. The thermodynamic and kinetic requirements for efficiency of PEP process in each medium are investigated and discussed on the basis of the light absorption abilities and electrochemical redox potentials measured for the two organic sensitizers.
|
|
| 37. |
- Zhang, Jinbao, et al.
(författare)
-
Poly(3,4-ethylenedioxythiophene) Hole-Transporting Material Generated by Photoelectrochemical Polymerization in Aqueous and Organic Medium for All-Solid-State Dye-Sensitized Solar Cells
- 2014
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:30, s. 16591-16601
-
Tidskriftsartikel (refereegranskat)abstract
- We applied organic donor-pi-acceptor (D-pi-A) sensitizers for photoelectrochemical polymerization (PEP) because of their appropriate energy levels and high light absorption. The polymerized conducting polymer PEDOT was used as hole conductor in all-solid-state dye-sensitized solar cells (ssDSCs). By combination of the D-pi-A sensitizers and the generated PEDOT from PEP of bis-EDOT in acetonitrile, the resulting device showed an average power conversion efficiency of 5.6%. Furthermore, the PEP in aqueous micellar electrolytic medium was also employed because of the ability to decrease oxidation potential of the precursor, thereby making the polymerization process easier. The latter method is a cost-effective and environmentally friendly approach. Using as hole conductor the so-obtained PEDOT from PEP of bis-EDOT in aqueous electrolyte, the devices exhibited impressive power conversion efficiency of 5.2%. To compare the properties of the generated polymer from bis-EDOT in these two PEP methods, electron lifetime, photoinduced absorption (PIA) spectra, and UV-vis-NIR spectra were measured. The results showed that PEDOT from organic PEP exhibits a delocalized conformation with high conductivity and a smooth and compact morphology; a rough morphology with high porosity and polymer structure of relatively shorter chains was assumed to be obtained from aqueous PEP. Therefore, better dye regeneration but faster charge recombination was observed in the device based on PEDOT from aqueous PEP of bis-EDOT. Subsequently, to extend the aqueous PEP approach in consideration of the ability to decrease the oxidation potential of the precursor, the easily available precursor EDOT was for the first time used for PEP in aqueous medium in a variant of the aforementioned procedure, and the device based on the so-obtained PEDOT shows a more than 70-fold increase in efficiency, 3.0%, over that based on the polymer generated from EDOT by PEP in organic media. It was demonstrated that aqueous micellar PEP with EDOT as monomer is an efficient strategy for generation of conducting polymer hole-transporting materials.
|
|
| 38. |
- Zhang, Jinbao, et al.
(författare)
-
Solid-State Dye-Sensitized Solar Cells Based on Poly( 3,4ethylenedioxypyrrole) and Metal-Free Organic Dyes
- 2014
-
Ingår i: ChemPhysChem. - : Wiley. - 1439-4235 .- 1439-7641. ; 15:6, s. 1043-1047
-
Tidskriftsartikel (refereegranskat)abstract
- Poly(3,4-ethylenedioxypyrrole) (PEDOP), combined with metal-free organic sensitizers, is efficiently used for the first time as the hole-transporting material in solid-state dye-sensitized solar cells. Devices employing PEDOP as the hole conductor and D35 or D21 L6 as the sensitizer show a ten-times-higher energy-conversion efficiency (of 4.5% and 3.3%, respectively) compared to Ru-Z907-based devices. This is due to the efficient suppression of electron recombination.
|
|
| 39. |
- Zhang, Jinbao, et al.
(författare)
-
Strategy to Boost the Efficiency of Mixed-Ion Perovskite Solar Cells : Changing Geometry of the Hole Transporting Material
- 2016
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 10:7, s. 6816-6825
-
Tidskriftsartikel (refereegranskat)abstract
- The hole transporting material (HTM) is an essential component in perovskite solar cells (PSCs) for efficient extraction and collection of the photoinduced charges. Triphenylamine- and carbazole-based derivatives have extensively been explored as alternative and economical HTMs for PSCs. However, the improvement of their power conversion efficiency (PCE), as well as further investigation of the relationship between the chemical structure of the HTMs and the photovoltaic performance, is imperatively needed. In this respect, a simple carbazole-based HTM X25 was designed on the basis of a reference HTM, triphenylamine-based X2, by simply linking two neighboring phenyl groups in a triphenylamine unit through a carbon-carbon single bond. It was found that a lowered highest occupied molecular orbital (HOMO) energy level was obtained for X25 compared to that of X2. Besides, the carbazole moiety in X25 improved the molecular planarity as well as conductivity property in comparison with the triphenylamine unit in X2. Utilizing the HTM X25 in a solar cell with mixed-ion perovskite [HC(NH2)(2)](0.85)(CH3NH3)(0.15)Pb(I0.85Br0.15)(3), a highest reported PCE of 17.4% at 1 sun (18.9% under 0.46 sun) for carbazole-based HTM in PSCs was achieved, in comparison of a PCE of 14.7% for triphenylamine-based HTM X2. From the steady-state photoluminescence and transient photocurrent/photovoltage measurements, we conclude that (1) the lowered HOMO level for X25 compared to X2 favored a higher open-circuit voltage (V-oc) in PSCs; (2) a more uniform formation of X25 capping layer than X2 on the surface of perovskite resulted in more efficient hole transport and charge extraction in the devices. In addition, the long-term stability of PSCs with X25 is significantly enhanced compared to X2 due to its good uniformity of HTM layer and thus complete coverage on the perovskite. The results provide important information to further develop simple and efficient small molecular HTMs applied in solar cells.
|
|
| 40. |
- Zhang, Jinbao, et al.
(författare)
-
The effect of mesoporous TiO2 pore size on the performance of solid-state dye sensitized solar cells based on photoelectrochemically polymerized Poly(3,4-ethylenedioxythiophene) hole conductor
- 2016
-
Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 210, s. 23-31
-
Tidskriftsartikel (refereegranskat)abstract
- Photoelectrochemical polymerization of poly(3,4-ethylenedioxythiphene) (PEDOT) has recently been introduced and widely investigated for fabrication of the hole transporting material (HTM) in highly efficient solid state dye sensitized solar cells (sDSCs). In this work, the effects of the surface area and pore size of TiO2 film were for the first time investigated in the sDSCs employing the in-situ polymerizated PEDOT HTM. Three different varieties of mesoporous TiO2 particles with controllable surface area and pore size were synthesized through the basic route in order to study the corresponding sDSC photovoltaic performances. It was found that the pore size plays an important role in the kinetics of the photoelectrochemical polymerization (PEP) process and the formation of the PEDOT capping layer. Larger pore sizes provided a more favourable pathway for the precursor diffusion through the mesoporous pores during the PEP process, which contributed towards a more efficient PEP. However, the interfacial contact area between the formed polymer and the dyes on the surface of TiO2 particle would be lower in the case of larger pore sizes, which consequently caused a less efficient dye regeneration process. Electronic diffusion on the other hand was improved for larger particle sizes. Employing an organic dye LEG4 and the self-made TiO2 with an optimal pore size of 25 nm and particle size of 24 nm, the sDSCs showed a promising power conversion efficiency (PCE) of 5.2%, higher than 4.5% for the commercial TiO2 Dyesol DSL-30. By measuring the dye regeneration yield and the kinetics through photoinduced absorption, it was observed that the homemade TiO2 based device had more efficient dye regeneration compared to the Dyesol based device, which could result from the better interfacial contact between the PEDOT and the dye. This work provides important information on the effect of meso-pore size on sDSCs and points to the necessity of further photoanode optimization toward the enhancement of the PCE of polymeric hole conductor-based DSCs.
|
|
| 41. |
- Zhang, Jinbao, et al.
(författare)
-
The Importance of Pendant Groups on Triphenylamine-Based Hole Transport Materials for Obtaining Perovskite Solar Cells with over 20% Efficiency
- 2018
-
Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 18:2
-
Tidskriftsartikel (refereegranskat)abstract
- Tremendous progress has recently been achieved in the field of perovskite solar cells (PSCs) as evidenced by impressive power conversion efficiencies (PCEs); but the high PCEs of >20% in PSCs has so far been mostly achieved by using the hole transport material (HTM) spiro-OMeTAD; however, the relatively low conductivity and high cost of spiro-OMeTAD significantly limit its potential use in large-scale applications. In this work, two new organic molecules with spiro[fluorene-9,9-xanthene] (SFX)-based pendant groups, X26 and X36, have been developed as HTMs. Both X26 and X36 present facile syntheses with high yields. It is found that the introduced SFX pendant groups in triphenylamine-based molecules show significant influence on the conductivity, energy levels, and thin-film surface morphology. The use of X26 as HTM in PSCs yields a remarkable PCE of 20.2%. In addition, the X26-based devices show impressive stability maintaining a high PCE of 18.8% after 5 months of aging in controlled (20%) humidity in the dark. We believe that X26 with high device PCEs of >20% and simple synthesis show a great promise for future application in PSCs, and that it represents a useful design platform for designing new charge transport materials for optoelectronic applications.
|
|
| 42. |
- Zhang, Xiaoliang, et al.
(författare)
-
ZnO@Ag2S core-shell nanowire arrays for environmentally friendly solid-state quantum dot-sensitized solar cells with panchromatic light capture and enhanced electron collection
- 2015
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 17:19, s. 12786-12795
-
Tidskriftsartikel (refereegranskat)abstract
- A solid-state environmentally friendly Ag2S quantum dot-sensitized solar cell (QDSSC) is demonstrated. The photovoltaic device is fabricated by applying ZnO@Ag2S core-shell nanowire arrays (NWAs) as light absorbers and electron conductors, and poly-3-hexylthiophene (P3HT) as a solid-state hole conductor. Ag2S quantum dots (QDs) were directly grown on the ZnO nanowires by the successive ionic layer adsorption and reaction (SILAR) method to obtain the core-shell nanostructure. The number of SILAR cycles for QD formation and the length of the core-shell NWs significantly affect the photocurrent. The device with a core-shell NWAs photoanode shows a power conversion efficiency increase by 32% compared with the device based on a typical nanoparticle-based photoanode with Ag2S QDs. The enhanced performance is attributed to enhanced collection of the photogenerated electrons utilizing the ZnO nanowire as an efficient pathway for transporting the photogenerated electrons from the QD to the contact.
|
|
