| 1. |
- Chakraborty, Sudip, et al.
(författare)
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Rational Design : A High-Throughput Computational Screening and Experimental Validation Methodology for Lead-Free and Emergent Hybrid Perovskites
- 2017
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 2:4, s. 837-845
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells, with efficiencies of 22.1%, are the only solution-processable technology to outperform multicrystalline silicon and thin-film solar cells. Whereas substantial progress has been made in scalability and stability, toxicity concerns drive the need for lead replacement, intensifying research into the broad palette of elemental substitutions, solid solutions, and multidimensional structures. Perovskites have gone from comprising three to more than eight (CH3NH3, HC(NH2)(2), Cs, Rb, Pb, Sn, I, Br) organic and inorganic constituents, and a variety of new embodiments including layered, double perovskites, and metal-deficient perovskites are being explored. Although most experimentation is guided by intuition and trial-and-error-based Edisonian approaches, rational strategies underpinned by computational screening and targeted experimental validation are emerging. In addressing emergent perovskites, this perspective discusses the rational design methodology leveraging density functional theory-based high-throughput computational screening coupled to downselection strategies to accelerate the discovery of materials and industrialization of perovskite solar cells.
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| 2. |
- Koh, Teck Ming, et al.
(författare)
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Influence of 4-tert-Butylpyridine in DSCs with Co-II/III Redox Mediator
- 2013
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:30, s. 15515-15522
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Tidskriftsartikel (refereegranskat)abstract
- The effect of TBP on Co(II/III) redox electrolyte was examined. Photocurrent of the device can be limited in electrolyte with high TBP concentration due to its viscous nature. The higher amount of TBP in electrolyte increases the viscosity of electrolyte and consequently slows down the diffusion of Co-III species. This is a unique observation for Co(II/III) electrolyte which is not observed in I-/I-3(-) electrolyte. An increase in TBP concentration from 0.1 to 0.5 M in a cobalt electrolyte containing 0.1 M Co(bpy)(3)(TFSI)(2) and 0.033 M Co(bpy)(3)(TFSI)(3) produced a 90 mV improvement in open-circuit potential (V-oc). Using electrochemical impedance spectroscopy (EIS), this enhancement could be attributed to the reduced interfacial recombination (33%) as well as a negative shift in the conduction 0 band level of TiO2 (67%). Although the influence of TBP in iodide/triiodide and cobalt-complex electrolytes is similar, the increase of viscosity at relatively high concentration of TBP in Co electrolyte should be taken into consideration in order to accomplish high efficiency DSCs based on Co-complex electrolytes.
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| 3. |
- Koh, Teck Ming, et al.
(författare)
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Photovoltage enhancement from cyanobiphenyl liquid crystals and 4-tert-butylpyridine in Co(II/III) mediated dye-sensitized solar cells
- 2013
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 49:80, s. 9101-9103
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Tidskriftsartikel (refereegranskat)abstract
- Two cyanobiphenyl liquid crystals (LCs), 5CB (4-cyano-4'-pentylbiphenyl) and 8CB (4-cyano-4'-octylbiphenyl), are introduced as additives into Co(II/ III) electrolytes for dye-sensitized solar cells (DSCs). An electrolyte containing a combination of these LCs and 4-tert-butylpyridine (TBP) exhibits higher photovoltage than one with only TBP, resulting in higher power conversion efficiency.
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| 4. |
- Li, Hairong, et al.
(författare)
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A Simple 3,4-Ethylenedioxythiophene Based Hole-Transporting Material for Perovskite Solar Cells
- 2014
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 53:16, s. 4085-4088
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel electron-rich molecule based on 3,4-ethylenedioxythiophene (H101). When used as the hole-transporting layer in a perovskite-based solar cell, the power-conversion efficiency reached 13.8% under AM 1.5G solar simulation. This result is comparable with that obtained using the well-known hole transporting material 2,2,7,7-tetrakis(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene (spiro-OMeTAD). This is the first heterocycle-containing material achieving >10% efficiency in such devices, and has great potential to replace the expensive spiro-OMeTAD given its much simpler and cheaper synthesis.
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| 5. |
- Li, Hairong, et al.
(författare)
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Hole-Transporting Small Molecules Based on Thiophene Cores for High Efficiency Perovskite Solar Cells
- 2014
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 7:12, s. 3420-3425
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Tidskriftsartikel (refereegranskat)abstract
- Two new electron-rich molecules, 2,3,4,5-tetra[4,4'-bis(methoxyphenyl)aminophen-4 ''-yl]-thiophene (H111) and 4,4',5,5'-tetra[4,4'-bis(methoxyphenyl) aminophen-4 ''-yl]-2,2'-bithiophene (H112), which contain thiophene cores with arylamine side groups, are reported. When used as the hole-transporting material (HTM) in perovskite-based solar cell devices, power conversion efficiencies of up to 15.4% under AM 1.5G solar simulation were obtained. This is the highest efficiency achieved with HTMs not composed of 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) and its isomers. Both HTMs, especially H111, have great potential to replace expensive spiro-OMeTAD given their much simpler and less expensive syntheses.
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| 6. |
- Li, Hairong, et al.
(författare)
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New donor-pi-acceptor sensitizers containing 5H-[1,2,5]thiadiazolo [3,4-f]isoindole-5,7(6H)-dione and 6H-pyrrolo[3,4-g]quinoxaline-6,8(7H)-dione units
- 2013
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 49:24, s. 2409-2411
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Tidskriftsartikel (refereegranskat)abstract
- Two new D-pi-A sensitizers (L101 and L102) incorporating 5H-[1,2,5]thiadiazolo [3,4-f] isoindole-5,7(6H)-dione and 6H-pyrrolo[3,4-g]quinoxaline-6,8(7H)-dione core structures were synthesized and tested in liquid dye-sensitized solar cells (DSCs). L102 achieved a promising power conversion efficiency (PCE) of 6.2% (AM 1.5, 100 mW cm(-2)).
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| 7. |
- Mathews, Nripan, et al.
(författare)
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Oxide nanowire networks and their electronic and optoelectronic characteristics
- 2010
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Ingår i: Nanoscale. - Cambridge : RSC Publishing. - 2040-3364 .- 2040-3372. ; 2:10, s. 1984-1998
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Tidskriftsartikel (refereegranskat)abstract
- Oxide nanowire networks or oxide nanonets leverage some of the exceptional functionalities of one-dimensional nanomaterials along with the fault tolerance and flexibility of interconnected nanowires to creating exciting opportunities in large-area electronics as well as green energy systems. This paper reviews the electronic and optoelectronic properties of these networks and highlights their potential applications in field-effect transistors, optoelectronic devices, and solar cells. Techniques to grow nanowires and their subsequent integration into networks using contact printing and electrospinning are described. Electrical properties of field-effect transistors fabricated from contact printed nanowire networks are discussed, and means of integration of the nanowire networks of heterogenous materials that enable ambipolar device operation are outlined. Photocurrent properties of these nanowires are described, including the dye sensitization of large-bandgap SnO2 nanowires. The final section deals with the advantages of employing nanowire networks in dye-sensitized solar cells and the dependence of solar cell performance on morphology and surface area. © The Royal Society of Chemistry 2010.
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| 8. |
- Zhang, Keke K., et al.
(författare)
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Control of charge mobility in single-crystal rubrene through surface chemistry
- 2010
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Ingår i: Organic electronics. - : Elsevier BV. - 1566-1199 .- 1878-5530. ; 11:12, s. 1928-1934
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Tidskriftsartikel (refereegranskat)abstract
- The mobility of rubrene single-crystal field-effect transistors has been measured in the presence of hydrogen and oxygen gas. The mobility of as-grown crystals is similar to 10 cm(2)/V s but falls to 0.01 cm(2)/V s during reduction in a hydrogen environment, and returns to nearly its original value in oxygen. Several cycles of surface reduction and oxidation have been done, which indicates that the surface reactions are reversible and the mobility can be changed to any value between that of the oxidized surface (10 cm(2)/V s) and that of the reduced surface (0.01 cm(2)/V s). Fourier-transform infrared (FTIR) spectroscopy and photoluminescence (PL) spectroscopy have been applied to examine the oxidized and reduced surface of the rubrene single crystal. FTIR, Raman and PL spectroscopies reveal differences between the rubrene surface and bulk depending on the state of surface oxidation. We conclude that high field-effect mobility in rubrene crystals is a result of surface doping by an oxidized layer on the crystal surface and not due to the intrinsic molecular and crystal structure of rubrene.
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