Fabrication of robust and highly stable Al2O3 passivated CdS anchored ZnO-Si nanowires: A new paradigm for hierarchical structure and sustainable solar fuel generation

We report sequential fabrication of a three-dimensional hierarchical structure of Al2O3 -passivated-CdS-anchored high quality ZnO nanowire (NW) on patterned silicon NWs (Al/CdS/Si-ZnO HNWs) realized using Metal Organic Chemical Vapor Deposition for photoelectrochemical water splitting. Further, to improve PEC performance and photostability CdS anchoring and Al2O3 passivation were carried out. The optimally designed 60 CdS/Si-ZnO HNWs showed 25.8-fold (1.79%) enhancement in the photoconversion efficiency at 0.3 V vs Ag/AgCl compared to bare Si-ZnO HNWs (0.069%) along with 47.8-fold enhancement in the photocurrent density (1.42 mA/cm(2) at 0 V vs Ag/AgCl). Further to improve the photostability (22.22 h) and reduce the photocorrosion, optimized 60 CdS/ZnO-Si HNWs were passivated using ultrathin Al2O3. Hierarchical assembly plays a key role in achieving the high photoconversion efficiency and photostability. The rationally designed hierarchical NW photoanodes synergistically improves photocurrent and photostability and may initiate facile integration of II-VI material with Si and could open the path for the next generation applications like energy harvesting as well as energy conversion devices. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

We report the sequential fabrication of a three-dimensional hierarchical structure of Al2O3-passivated-CdS-anchored high-quality ZnO nanowire (NW) for photoelectrochemical water splitting. The optimized CdS/Si-ZnO HNWs show significant enhancements in photoconversion efficiency and photocurrent density compared to bare Si-ZnO HNWs. Furthermore, the photostability and photocorrosion resistance are improved by passivating the CdS/ZnO-Si HNWs using ultrathin Al2O3. The hierarchical NW photoanodes synergistically improve photocurrent and photostability, allowing for facile integration of II-VI materials with Si for next-generation energy applications.