Conjugated Polythiophene Frameworks as a Hole‐Selective Layer on Ta 3 N 5 Photoanode for High‐Performance Solar Water Oxidation

• Published in: Advanced functional materials 2024-08, Vol.34 (34)
• Main Authors: Yang, Jin Wook, Kwon, Hee Ryeong, Ji, Su Geun, Kim, Jaehyun, Lee, Sol A, Lee, Tae Hyung, Choi, Sungkyun, Cheon, Woo Seok, Kim, Younhwa, Park, Jungwon, Kim, Jin Young, Jang, Ho Won
• Format: Article
• Language: English
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202400806

Discovering a competent charge transport layer promoting charge separation in photoelectrodes is a perpetual pursuit in photoelectrochemical (PEC) water splitting to achieve high solar‐to‐hydrogen (STH) conversion efficiency. Here, a conjugated polythiophene framework (CPF‐TTB) on Ta 3 N 5 is elaborately electropolymerized, substantiating the hole transport behavior in their heterojunction. Tailored band structures of the CPF‐TTB/Ta 3 N 5 reinforce the separation of photogenerated carriers, elevating a fill factor of the photoanode modified with a cocatalyst. The enhanced hole extraction enables the NiFeO x /CPF‐TTB/Ta 3 N 5 /TiN photoanode to generate a remarkable water oxidation photocurrent density of 9.12 mA cm −2 at 1.23 V versus the reversible hydrogen electrode. A tandem device combining the photoanode with a perovskite/Si solar cell implements an unbiased solar water splitting with a STH conversion efficiency of 6.26% under parallel illumination mode. This study provides novel strategies in interface engineering for metal nitride‐based photoelectrodes, suggesting a promise of the organic–inorganic hybrid photoelectrode for high‐efficiency PEC water splitting.