Efficient and Stable Perovskite‐Based Photocathode for Photoelectrochemical Hydrogen Production

Abstract

Although organometal halide perovskites (OHPs) have desirable photovoltaic properties, their photoelectrochemical (PEC) water‐splitting application for hydrogen production is limited by the instability originating from their intrinsic ionic defects and hygroscopic vulnerability. Herein, a highly efficient and stable OHP‐based photocathode achieved by a new zwitterion (L‐proline) passivation and a eutectic gallium indium alloy (EGaIn) encapsulation method is described. The zwitterion, which has both cations and anions, can simultaneously passivate both positively and negatively charged defects in OHPs. The resulting OHP photovoltaic cells with passivated shows an over 20% power conversion efficiency with an open‐circuit voltage of 1.13 V and a short‐circuit current of 22.13 mA cm−2. The EGaIn‐incorporated Ti foil provides complete encapsulation from the external environment while maintaining good transport of photogenerated charges from OHPs. Thus, these photocathodes exhibit a remarkable average photocurrent density of 21.2 mA cm−2 which has less than 5% current loss between PV cells and PEC cells. More admirably, the photocathode has the highest stability over 54 hours under continuous full sunlight illumination in a sulfuric acid electrolyte.

Metal halide perovskites for photocatalysis applications

“…The perovskite photocathode is composed of glass substrate/ITO/PTAA/PFN-Br/perovskite MAPbI 3 /PC60BM/BCP/Cu, which exhibits a remarkable average photocurrent density of 21.2 mA cm −2 and the highest stability for over 54 hours under continuous light illumination. 188 Besides, a H 2 ase combined triple cation mixed halide (CsFAMA) perovskite photocathode has also been constructed for photocatalytic water splitting, which displays an H 2 production yield of 258 ± 55 μmol cm −2 in 12 h and the hydrogenase exhibits a turnover number of 1.9 × 10 6189 . 66 Combining the perovskite-based photocathode and photoanode together, Hongjun Chen constructed a monolithic architecture consisting of two encapsulated perovskite (FA 0.80 MA 0.15 Cs 0.05 PbI 2.55 Br 0.45 ) solar cells with low-cost earth-abundant CoP for the HER and FeNi(OH) x for the OER, respectively, achieving an overall solar-to-hydrogen efficiency of 8.54% and good stability over 20 h. 190…”

Bias-free solar hydrogen production at 19.8 mA cm−2 using perovskite photocathode and lignocellulosic biomass

“…In this regard, lead halide perovskites offer many advantages over conventional photocatalysts: they have a tunable bandgap and energy level, high absorption coefficient, and excellent charge transport 21 , 22 . Nevertheless, there have been only a few reports of perovskite-based photoelectrodes for solar hydrogen production 23 , 24 , and no report exists in conjunction with biomass oxidation due to their vulnerability to water.…”

Enabling Solar Hydrogen Production over Selenium: Surface State Passivation and Cocatalyst Decoration

“…Numerous semiconducting materials including elemental silicon, , metal oxides, , sulfides, , and nitrides have been intensively investigated as either a photocathode or a photoanode. Among them, one distinct class of photoelectrode consists of devices fabricated from photovoltaic (PV)-grade materials, such as Cu­(In,Ga)­S 2 , CdTe, Si, or halide perovskites, where the principles of PV cells resemble those of PEC cells. Markedly, some of the PEC cells derived from the PV-grade materials have demonstrated outstanding photoconversion efficiencies. , Hence, developing photoelectrodes from the PV-grade materials is promising.…”