| 1. |
- Bi, Dongqin, et al.
(författare)
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Effect of Different Hole Transport Materials on Recombination in CH3NH3PbI3 Perovskite-Sensitized Mesoscopic Solar Cells
- 2013
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 4:9, s. 1532-1536
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Tidskriftsartikel (refereegranskat)abstract
- We report on perovskite (CH3NH3)PbI3-sensitized solid-state solar cells using spiro-OMeTAD, poly(3-hexylthiophene-2,5-diyl) (P3HT) and 4-(diethylamino)benzaldehyde diphenylhydrazone (DEH) as hole transport materials (HTMs) with a light to electricity power conversion efficiency of 8.5%, 4.5%, and 1.6%, respectively, under AM 1.5G illumination of 1000 W/m(2) intensity. Photoinduced absorption spectroscopy (PIA) shows that hole transfer occurs from the (CH3NH3)PbI3 to HTMs after excitation of (CH3NH3)PbI3. The electron lifetime (tau(e)) in these devices are in the order Spiro-OMeTAD > P3HT > DEH, while the charge transport time (t(tr)) is rather similar. The difference in tau(e) can therefore explain the lower efficiency of the devices based on P3HT and DEH. This report shows that the nature of the HTM is essential for charge recombination and elucidates that finding an optimal HTM for the perovskite solar cell includes controlling the perovskite/HTM interaction. Design routes for new HTMs are suggested.
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| 2. |
- Bi, Dongqin, et al.
(författare)
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Efficient and stable CH3NH3PbI3-sensitized ZnO nanorod array solid-state solar cells
- 2013
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 5:23, s. 11686-11691
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Tidskriftsartikel (refereegranskat)abstract
- We report for the first time the use of a perovskite (CH3NH3PbI3) absorber in combination with ZnO nanorod arrays (NRAs) for solar cell applications. The perovskite material has a higher absorption coefficient than molecular dye sensitizers, gives better solar cell stability, and is therefore more suited as a sensitizer for ZnO NRAs. A solar cell efficiency of 5.0% was achieved under 1000 W m(-2) AM 1.5 G illumination for a solar cell with the structure: ZnO NRA/CH3NH3PbI3/spiro-MeOTAD/Ag. Moreover, the solar cell shows a good long-term stability. Using transient photocurrent and photovoltage measurements it was found that the electron transport time and lifetime vary with the ZnO nanorod length, a trend which is similar to that in dye-sensitized solar cells, DSCs, suggesting a similar charge transfer process in ZnO NRA/CH3NH3PbI3 solar cells as in conventional DSCs. Compared to CH3NH3PbI3/TiO2 solar cells, ZnO shows a lower performance due to more recombination losses.
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| 3. |
- Bi, Dongqin, et al.
(författare)
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High-Efficient Solid-State Perovskite Solar Cell Without Lithium Salt in the Hole Transport Material
- 2014
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Ingår i: NANO. - 1793-2920. ; 9:5, s. 1440001-
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Tidskriftsartikel (refereegranskat)abstract
- CH3NH3PbX (X Br, I, Cl) perovskites have recently been used as light absorbers in hybrid organic-inorganic solid-state solar cells, with efficiencies above 15%. To date, it is essential to add Lithium bis(Trifluoromethanesulfonyl) Imide (LiTFSI) to the hole transport materials (HTM) to get a higher conductivity. However, the detrimental er effect of high LiTFSI concentration on the charge transport, DOS in the conduction band of the TiO2 substrate and device stability results in an overall compromise for a satisfactory device. Using a higher mobility hole conductor to avoid lithium salt is an interesting alternative. Herein, we successfully made an efficient perovskite solar cell by applying a hole conductor PTAA (Poly[ bis(4-phenyl) (2,4,6-trimethylphenyl)amine]) in the absence of LiTFSI. Under AM 1.5 illumination of 100mW/cm(2), an efficiency of 10.9% was achieved, which is comparable to the efficiency of 12.3% with the addition of 1.3mM LiTFSI. An unsealed device without Li+ shows interestingly a promising stability.
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| 4. |
- Bi, Dongqin, et al.
(författare)
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Improved Morphology Control Using a Modified Two-Step Method for Efficient Perovskite Solar Cells
- 2014
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 6:21, s. 18751-18757
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Tidskriftsartikel (refereegranskat)abstract
- A two-step wet chemical synthesis method for methylammonium lead(II) triiodide (CH3NH3PbI3) perovskite is further developed for the preparation of highly reproducible solar cells, with the following structure: fluorine-doped tin oxide (FTO)/TiO2 (compact)/TiO2 (mesoporous)/CH3NH3PbI3/spiro-OMeTAD/Ag. The morphology of the perovskite layer could be controlled by careful variation of the processing conditions. Specifically, by modifying the drying process and inclusion of a dichloromethane treatment, more uniform films could be prepared, with longer emission lifetime in the perovskite material and longer electron lifetime in solar cell devices, as well as faster electron transport and enhanced charge collection at the selective contacts. Solar cell efficiencies up to 13.5% were obtained.
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| 5. |
- Bi, Dongqin, et al.
(författare)
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Unraveling the Effect of PbI2 Concentration on Charge Recombination Kinetics in Perovskite Solar Cells
- 2015
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 2:5, s. 589-594
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Tidskriftsartikel (refereegranskat)abstract
- CH3NH3PbI3 perovskite solar cells have rapidly risen to the forefront of emerging photovoltaic technologies. A solution-based, two-step method was reported to enhance the reproducibility of these solar cells. In this method, first a coating of PbI2 is applied by spin-coating onto a TiO2-coated substrate, followed by a dip in a methylammonium iodide solution, leading to conversion to CH3NH3PbI3. The concentration of PbI2 in the spin-coating solution is a very important factor that affects the infiltration of the perovskite and the amount deposited. The best solar cell performance of 13.9% was obtained by devices prepared using 1.0 M of PbI2 in dimethylformamide. These devices also had the longest electron lifetime and shortest carrier transport time, yielding lowest recombination losses. Rapid quenching of the perovskite emission is found in device-like structures, suggesting reasonably good efficient carrier extraction at the TiO2 interface and quantitative extraction at the spiro-OMeTAD interface.
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| 6. |
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| 7. |
- Li, Yahong, et al.
(författare)
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Recent Progress of Critical Interface Engineering for Highly Efficient and Stable Perovskite Solar Cells
- 2022
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Ingår i: Advanced Energy Materials. - : John Wiley & Sons. - 1614-6832 .- 1614-6840. ; 12:5
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Forskningsöversikt (refereegranskat)abstract
- Organic-inorganic lead halide perovskite solar cells (PSCs) have demonstrated enormous potential as a new generation of solar-based renewable energy. Although their power conversion efficiency (PCE) has been boosted to a spectacular record value, the long-term stability of efficient PSCs is still the dominating concern that hinders their commercialization. Notably, interface engineering has been identified as a valid strategy with extraordinary achievements for enhancing both efficiency and stability of PSCs. Herein, the latest research advances of interface engineering for various interfaces are summarized, and the basic theory and multifaceted roles of interface engineering for optimizing device properties are analyzed. As a highlight, the authors provide their insights on the deposition strategy of interlayers, application of first-principle calculation, and challenges and solutions of interface engineering for PSCs with high efficiency and stability toward future commercialization.
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| 8. |
- Lindbad, Rebecka, et al.
(författare)
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Electronic Structure of TiO2/CH(3)NH(3)Pbl(3) Perovskite Solar Cell Interfaces
- 2014
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 5:4, s. 648-653
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure and chemical composition of efficient CH(3)NH(3)Pbl(3) perovskite solar cell materials deposited onto mesoporous TiO2 were studied using photoelectron spectroscopy with hard X-rays. With this technique, it is possible to directly measure the occupied energy levels of the perovskite as well as the TiO2 buried beneath and thereby determine the energy level matching of the interface. The measurements of the valence levels were in good agreement with simulated density of states, and the investigation gives information on the character of the valence levels. We also show that two different deposition techniques give results indicating similar electronic structures.
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| 9. |
- Lindblad, Rebecka, et al.
(författare)
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Electronic Structure of CH3NH3PbX3 Perovskites : Dependence on the Halide Moiety
- 2015
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Ingår i: The Journal of Physical Chemistry C. - American Chemical Society : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 119:4, s. 1818-1825
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Tidskriftsartikel (refereegranskat)abstract
- A combination of measurements using photoelectron spectroscopy and calculations using density functional theory (DFT) was applied to compare the detailed electronic structure of the organolead halide perovskites CH3NH3PbI3 and CH3NH3PbBr3. These perovskite materials are used to absorb light in mesoscopic and planar heterojunction solar cells. The Pb 4f core level is investigated to get insight into the chemistry of the two materials. Valence level measurments are also included showing a shift of the valence band edges where there is a higher binding energy of the edge for the CH3NH3PbBr3 perovskite. These changes are supported by the theoretical calculations which indicate that the differences in electronic structure are mainly caused by the nature of the halide ion rather than structural differences. The combination of photoelectron spectroscopy measurements and electronic structure calculations is essential to disentangle how the valence band edge in organolead halide perovskites is governed by the intrinsic difference in energy levels of the halide ions from the influence of chemical bonding.
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| 10. |
- Lindblad, Rebecka, et al.
(författare)
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Electronic Structure of TiO2/CH3NH3PbI3 Perovskite Solar Cell Interfaces
- 2014
-
Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 5:4, s. 648-653
-
Tidskriftsartikel (refereegranskat)abstract
- The electronic structure and chemical composition of efficient CH3NH3PbI3 perovskite solar cell materials deposited onto mesoporous TiO2 were studied using photoelectron spectroscopy with hard X-rays. With this technique, it is possible to directly measure the occupied energy levels of the perovskite as well as the TiO2 buried beneath and thereby determine the energy level matching of the interface. The measurements of the valence levels were in good agreement with simulated density of states, and the investigation gives information on the character of the valence levels. We also show that two different deposition techniques give results indicating similar electronic structures.
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| 11. |
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| 12. |
- Song, Jing, et al.
(författare)
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Progress and Perspective on Inorganic CsPbI2Br Perovskite Solar Cells
- 2022
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Ingår i: Advanced Energy Materials. - : John Wiley & Sons. - 1614-6832 .- 1614-6840. ; 12:40
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Forskningsöversikt (refereegranskat)abstract
- Over the past few years, all-inorganic perovskite solar cells (PSCs), especially CsPbI2Br PSCs, have received much attention because of their excellent thermal stability and a suitable trade-off between light absorption and higher phase stability among the family of inorganic perovskites. In this progress report, the realization of highly efficient and stable CsPbI2Br PSCs is summarized through preparation process, additive engineering, interface modification, and transport material selection. Furthermore, the application of CsPbI2Br in tandem solar cells and its large-area development are highlighted. Finally, the challenges and outlook of CsPbI2Br PSCs are discussed for further performance improvement and future practical deployment.
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| 13. |
- Xu, Bo, et al.
(författare)
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A low-cost spiro[fluorene-9,9 '-xanthene]-based hole transport material for highly efficient solid-state dye-sensitized solar cells and perovskite solar cells
- 2016
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 9:3, s. 873-877
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Tidskriftsartikel (refereegranskat)abstract
- A low-cost spiro[fluorene-9,9'-xanthene] (SFX) based organic hole transport material (HTM) termed X60 was designed and synthesized using a two-step synthetic route. Devices with X60 as HTM showed high power conversion efficiencies (PCEs) amounting to 7.30% in solid-state dye-sensitized solar cells (ssDSCs) and 19.84% in perovskite solar cells (PSCs), under 100 mW cm(-2) AM1.5G solar illumination. To the best of our knowledge, this is the first example of an easily synthesized spiro-structured HTM that shows comparable performance with respect to the well-known HTM Spiro-OMeTAD in both ssDSCs and PSCs. Furthermore, the facile synthesis of X60 from commercially available starting materials makes this HTM very promising for large-scale industrial production in the future.
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| 14. |
- Xu, Bo, et al.
(författare)
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Efficient solid state dye-sensitized solar cells based on an oligomer hole transport material and an organic dye
- 2013
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496 .- 0959-9428 .- 1364-5501. ; 1:46, s. 14467-14470
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Tidskriftsartikel (refereegranskat)abstract
- A low-cost and easily-synthesized organic hole transport material (HTM) X3 bearing triphenylamine units and an organic dye was utilized for solid state dye sensitized solar cells (ssDSCs), which have achieved the power conversion efficiencies of 5.8% and 7.1% under 1 sun and 0.46 sun, respectively, outperforming the ssDSC based on Spiro-OMeTAD 5.4% (1 sun) and 6.4% (0.46 sun).
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| 15. |
- Yang, Lei, et al.
(författare)
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Initial Light Soaking Treatment Enables Hole Transport Material to Outperform Spiro-OMeTAD in Solid-State Dye-Sensitized Solar Cells
- 2013
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 135:19, s. 7378-7385
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Tidskriftsartikel (refereegranskat)abstract
- Efficient solid state dye-sensitized solar cells (sDSCs) were obtained using a small hole transport material, MeO-TPD (N,N,N',N'-tetrakis(4-methoxyphenyl)benzidine), after an initial light soaking treatment. It was discovered that the light soaking treatment for the MeO-TPD based solar cells is essential in order to achieve the high efficiency (4.9%), which outperforms spiro-OMeTAD based sDSCs using the same dye and device preparation parameters. A mechanism based on Li+ ion migration is suggested to explain the light soaking effect. It was observed that the electron lifetime for the MeO-TPD based sDSC strongly increases after the light soaking treatment, which explains the higher efficiency. After the initial light soaking treatment the device efficiency remains considerably stable with only 0.2% decrease after around 1 month (unsealed cells stored in dark).
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| 16. |
- Yang, Lei, et al.
(författare)
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New Approach for Preparation of Efficient Solid-State Dye-Sensitized Solar Cells by Photoelectrochemical Polymerization in Aqueous Micellar Solution
- 2013
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 4:23, s. 4026-4031
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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.
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