Silver Bismuth Sulfoiodide Solar Cells: Tuning Optoelectronic Properties by Sulfide Modification for Enhanced Photovoltaic Performance. Issue 5 (14th December 2018)

• Record Type: Journal Article
• Authors: Pai, Narendra; Lu, Jianfeng; Gengenbach, Thomas R.; Seeber, Aaron; Chesman, Anthony S. R.; Jiang, Liangcong; Senevirathna, Dimuthu C.; Andrews, Philip C.; Bach, Udo; Cheng, Yi‐Bing; Simonov, Alexandr N.
• Is Part Of: Advanced energy materials. Volume 9:Issue 5(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-12-14
• Subjects: bandgap -- iodide sulfide -- mixed anion -- valence band -- lead free; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201803396
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Silver bismuth iodides (Ag a Bi b I a +3 b ) are nontoxic and comparatively cheap photovoltaic materials, but their wide bandgaps and downshifted valence band edges limit their performance as light absorbers in solar cells. Herein, a strategy is introduced to tune the optoelectronic properties of Ag a Bi b I a +3 b by partial anionic substitution with the sulfide dianion. A consistent narrowing of the bandgap by 0.1 eV and an upshift of the valence band edge by 0.1–0.3 eV upon modification with sulfide are demonstrated for AgBiI4, Ag2 BiI5, Ag3 BiI6, and AgBi2 I7 compositions. Solar cells based on silver bismuth sulfoiodides embedded into a mesoporous TiO2 electron‐transporting scaffold, and a poly[bis(4‐phenyl)(2, 4, 6‐trimethylphenyl)amine] hole‐transporting layer significantly outperform devices based on sulfide‐free materials, mainly due to enhancements in the photocurrent by up to 48%. A power conversion efficiency of 5.44 ± 0.07% ( J sc = 14.6 ± 0.1 mA cm −2 ; V oc = 569 ± 3 mV; fill factor = 65.7 ± 0.3%) under 1 sun irradiation and stability under ambient conditions for over a month are demonstrated. The results reported herein indicate that further improvements should be possible with this new class of photovoltaic materials upon advances in the synthetic procedures and an increase in the level of sulfide anionic substitution. Abstract : A new class of inorganic photovoltaic materials, silver bismuth iodide sulfides, is introduced . The optoelectronic properties of these compounds can be tuned by variation of the sulfide to iodide ratio. Thin solar cells based on Ag a Bi b I a +3 b −2 x S x light harvesters exhibit power conversion efficiencies above 5%, are stable under ambient conditions and can be produced on the centimeter‐size scale.