Oxalate Pushes Efficiency of CsPb_0.7Sn_0.3IBr₂ Based All‐Inorganic Perovskite Solar Cells to over 14%

Abstract

All‐inorganic CsPbIBr2 perovskite solar cells (PSCs) have recently gained growing attention as a promising template to solve the thermal instability of organic–inorganic PSCs. However, the relatively low device efficiency hinders its further development. Herein, highly efficient and stable CsPb0.7Sn0.3IBr2 compositional perovskite‐based inorganic PSCs are fabricated by introducing appropriate amount of multifunctional zinc oxalate (ZnOX). In addition to offset Pb and Sn vacancies through Zn2+ ions incorporation, the oxalate group can strongly interact with undercoordinated metal ions to regulate film crystallization, delivering perovskite film with low defect density, high crystallinity, and superior electronic properties. Correspondingly, the resulting device delivers a champion efficiency of 14.1%, which presents the highest reported efficiency for bromine‐rich inorganic PSCs thus far. More importantly, chemically reducing oxalate group can effectively suppress the notorious oxidation of Sn2+, leading to significant enhancement on air stability.

All-inorganic perovskite solar cells featuring mixed group IVA cations

“…A seed-assisted growth (SAG) method was used to fabricate a series of high-quality CsPb 1− x Sn x IBr 2 films. 69 To inhibit the oxidation of Sn 2+ to Sn 4+ , reduce the trap density and improve the perovskite film morphology, zinc oxalate (ZnO x ) was introduced into the perovskite precursor solution as an additive. Fig.…”

Surface Modification in CsPb0.5Sn0.5I2Br Inorganic Perovskite Solar Cells: Effects of Bifunctional Dipolar Molecules on Photovoltaic Performance

“…The inorganic perovskites exhibit higher compositional stability compared to organic–inorganic hybrid perovskites, which facilitates the preparation of highly stable solar cells. − Unfortunately, according to the Shockley–Queisser efficiency limit, the most advanced inorganic perovskites, CsPbI 3 , exhibit large optical bandgaps (1.73 eV), which drastically lowers the power conversion efficiency (PCE) in a single-junction solar cell . Moreover, even at room temperature, CsPbI 3 is prone to phase transitions from black α-phase to yellow δ-phase. − …”

First-principles study on the optoelectronic and mechanical properties of all-inorganic lead-free fluoride perovskites ABF3 (A = Na, K and B = Si, Ge)

“…They synthesized high quality CsPbI 3 films by using a combination of air-flow-assisted drying and the addition of organic Lewis acid Zn(C 6 F 5 ) 2 , demonstrating that the PSC degrades by only ∼2% after 700 h under air conditions without any encapsulation. However, perovskite CsPbI 3 in the cubic phase has an intrinsic instability problem caused by phase transition, promoting the development of various methods such as nanostructuring, 26–28 ion substitution 29 and hybridization ( e.g. , (CsMA)PbI 3 ) 12,30 .…”