Water-resistant perovskite-inspired copper/silver pnictohalide nanocrystals for photoelectrochemical water splitting
Maning Liu, G. Krishnamurthy Grandhi, Basheer Al‐Anesi, Harri Ali‐Löytty, Kimmo Lahtonen, Roberto Grisorio, Paola Vivo
Abstract
Lead halide perovskites (LHPs) photoelectrodes for photoelectrochemical (PEC) water splitting are promising candidates for solar-to-fuel conversion. However, the poor stability of LHPs in aqueous electrolyte media, together with the toxicity of lead, restricts the practical application of LHP photoelectrodes. Herein, we report the first-ever colloidal synthesis of quaternary Cu1.4Ag0.6BiI5 nanocrystals (NCs), a new lead-free perovskite-inspired nanomaterial, by a facile hot injection method. The Cu1.4Ag0.6BiI5 NCs exhibit an extraordinary water resistance, due to the well-defined coverage of hydrophobic ligands on the surface of NCs with unique layered cation disordered structure. Together with their high structural stability, the Cu1.4Ag0.6BiI5 NCs-based photoanode displays a maximum photocurrent density of 4.62 mA cm−2 at 1.23 V vs. reversible hydrogen electrode, and an applied bias photo-to-current efficiency of 2.94% without any protective layer. Our study highlights the great potential of lead-free Cu1.4Ag0.6BiI5 NCs-based photoelectrodes for a wide range of low-cost, eco-friendly, and high-performance PEC applications.