Cs₂PtI₆ Halide Perovskite is Stable to Air, Moisture, and Extreme pH: Application to Photoelectrochemical Solar Water Oxidation

Abstract

Halide perovskites show incredible photovoltaic power conversion efficiency coupled with several hundreds of hours of device stability. However, their stability is poor in aqueous electrolyte media. Reported here is a vacancy ordered halide perovskite, Cs2PtI6, which shows extraordinary stability under ambient conditions (1 year), in aqueous media of extreme acidic (pH 1), basic (pH 13), and under electrochemical reduction conditions. It was employed as an electrocatalyst and photoanode for hydrogen production and water oxidation, respectively. The catalyst remains intact for at least 100 cycles of electrochemical cycling and six hours of hydrogen production at pH 1. Cs2PtI6 was employed as a photoanode for PEC water oxidation, and the material displayed a photocurrent of 0.8 mA cm−2 at 1.23 V (vs. RHE) under simulated AM1.5G sunlight. Using constant voltage measurement, Cs2PtI6 exhibited over 12 hours of PEC stability without loss of performance.

Computational screening of Cs based vacancy‐ordered double perovskites for solar cell and photocatalysis applications

“…Note that since the was not verified on vacancy‐ordered double perovskite A 2 BX 6 , its accuracy could be in doubt. Cs 2 PtI 6 , for instance, has been successfully synthesized and investigated effectively, and it is not capable of forming stable perovskite as predicted by the 11,56 …”

Halide Perovskites for Photoelectrochemical Water Splitting and CO2 Reduction: Challenges and Opportunities

“…Lead-free halide perovskites in both bulk and nanocrystal forms have shown their great potential in fulfilling this intrinsic requirement. Hamdan and co-workers 136 3f). More recently, lead-free double perovskite nanocrystals, i.e., Cs 4 CuSb 2 C1 12 NCs, 138 also showed promising photoelectrochemical performance, due to the nature of the direct band gap together with the lower effective mass, which was realized by transforming bulk Cs 4 CuSb 2 C 12 crystals into nanocrystals.…”

“…Lead-free halide perovskites in both bulk and nanocrystal forms have shown their great potential in fulfilling this intrinsic requirement. Hamdan and co-workers 136 prepared a thin photodiode based on a 3D Cs 2 PtI 6 perovskite thin film without any protective layers for water oxidation, showing extremely high stability against high temperature and extremely acidic and basic electrolytes (pH = 11). A moderate photocurrent density of 0.8 mA cm –2 was obtained at 1.23 V RHE (100 mW cm –2 ) with continuous operation for more than 12 h. In addition, Peng and co-workers 137 synthesized ligand-free Cs 2 PtBr 6 NCs, with a corresponding band gap of 1.32 eV with excellent conductivity, which are highly stable against high temperature, moisture and light radiation; the photoelectrodes based on Cs 2 PtBr 6 NCs in PEC tests achieved a maximum photocurrent density of 335 μA cm –2 at −0.6 V Ag/AgCl under LED light (10.18 mW cm –2 ), dramatically outperforming PEC systems based on CsPbBr 3 NCs and Cs 2 PdBr 6 NCs (see comparison of photocurrent densities in Figure 3 f).…”

Recent Trends and Challenges in Lead-Free Perovskite Solar Cells: A Critical Review

“…Figure shows the double perovskite structure. Although Pb is more toxic than Ag, it clearly does not mean that any trivalent M′ 3+ and monovalent M + cation can replace a Pb 2+ cation to produce 3D double perovskite AMM′X 6 . , M may be replaced by M = Pd 4+ , Nb 4+ , Pt 4+ , or Ti 4+ , ,− but among them, Cs 2 TiBr 6 and Cs 2 PtI 6 have shown promise for absorbing light due to their high absorption coefficient, appropriate bandgaps, excellent stability, large carrier lifetime, and attractive PCE. , The double perovskite is new family of lead-free perovskites, and with talk about Ag, only few (around 11) optimized samples with suitable bandgaps have been discovered. However, Cs 2 AgBiBr 6 , Cs 2 AgBiCl 6 , and (CH 3 NH 3 ) 2 AgBiBr 6 are the ones that have drawn considerable attention. − Cs 2 AgBiBr 6 films possess longer radiative recombination lifetimes and have better stability in comparison to MAPbI 3 films.…”