Organometal Halide Perovskite-Based Photoelectrochemical Module Systems for Scalable Unassisted Solar Water Splitting

Abstract

Despite achievements in the remarkable photoelectrochemical (PEC) performance of photoelectrodes based on organometal halide perovskites (OHPs), the scaling up of small-scale OHP-based PEC systems to large-scale systems remains a great challenge for their practical application in solar water splitting. Significant resistive losses and intrinsic defects are major obstacles to the scaling up of OHP-based PEC systems, leading to the PEC performance degradation of large-scale OHP photoelectrodes. Herein, a scalable design of the OHP-based PEC systems by modularization of the optimized OHP photoelectrodes exhibiting a high solar-to-hydrogen conversion efficiency of 10.4% is suggested. As a proof-of-concept, the OHP-based PEC module achieves an optimal PEC performance by avoiding major obstacles in the scaling up of the OHP photoelectrodes. The constructed OHP module is composed of a total of 16 OHP photoelectrodes, and a photocurrent of 11.52 mA is achieved under natural sunlight without external bias. The successful operation of unassisted solar water splitting using the OHP module without external bias can provide insights into the design of scalable OHP-based PEC systems for future practical application and commercialization.

Keywords: module; organometal halide perovskite; photoelectrochemical water splitting; scalable; unassisted solar water splitting.

Figure 1

PV performance of the n–i–p and p–i–n OHP PV cells. Representative J−V curves of the a) n–i–p and b) p–i–n OHP PV cells. c) EQE spectra and corresponding integrated J _SC of the n–i–p and p–i–n OHP PV cells. d) Stability of the n–i–p and p–i–n OHP PV cells.

Figure 2

Morphological and structural characteristics of catalyst‐integrated encapsulation layers. FESEM images of the a,b) NiFe LDH/Ni foil and c,d) NiMo/Ni foil with different magnifications. XRD patterns of the e) NiFe LDH/Ni foil, f) Ni/Cu foil, and NiMo/Cu foil. The insets show expanded regions of the XRD patterns.

Figure 3

Schematic representations and PEC performance of the OHP photoelectrodes. a) Fabrication process of the vertically stacked NiFe LDH/Ni foil/OHP photoanode and NiMo/Ni foil/OHP photocathode. Representative CV curves of the b) NiFe LDH/Ni foil/OHP photoanode, and c) NiMo/Ni foil/OHP photocathode.

Figure 4

PEC performance of the OHP dual photoelectrodes for unassisted solar water splitting. a) Schematic representation of the OHP‐based PEC systems for unassisted solar water splitting and the corresponding band alignment. b) Combined CV curves of the OHP photoanode and photocathode for expectation of the operating point of the dual photoelectrodes. c) Representative LSV curve of the OHP dual photoelectrodes using a two‐electrode configuration. d) Chronoamperometric measurement for evaluation of the PEC stability of the OHP dual photoelectrodes without external bias.

Figure 5

PEC performance of the OHP module for unassisted solar water splitting under natural sunlight. a) Schematic representation and b) photograph of the OHP module. c) Representative LSV curves of the OHP module with different solar irradiance of natural sunlight. d) Chronoamperometric measurement for real‐world verification of the OHP module without external bias as well as real‐time solar irradiance evaluation. The inset shows a photograph of the sky at 01:53 PM.