Ligand-Engineered Quantum Dots Decorated Heterojunction Photoelectrodes for Self-Biased Solar Water Splitting

Mengke Cai; Xin Tong; Hongyang Zhao; Xin Li; Yimin You; Rui Wang; Li Xia; Nan Zhou; Lianzhou Wang; Zhiming M Wang

doi:10.1002/smll.202204495

Ligand-Engineered Quantum Dots Decorated Heterojunction Photoelectrodes for Self-Biased Solar Water Splitting

Small. 2022 Nov;18(46):e2204495. doi: 10.1002/smll.202204495. Epub 2022 Sep 23.

Authors

Mengke Cai^{1

2}, Xin Tong^{1

2}, Hongyang Zhao¹, Xin Li¹, Yimin You¹, Rui Wang¹, Li Xia¹, Nan Zhou¹, Lianzhou Wang³, Zhiming M Wang^{1

4}

Affiliations

¹ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, China.
² Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou, 313001, China.
³ Nanomaterials Centre, School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia.
⁴ Institute for Advanced Study, Chengdu University, Chengdu, 610106, China.

PMID: 36148833
DOI: 10.1002/smll.202204495

Abstract

A cost-effective and high-efficiency photoelectrochemical (PEC) water splitting system based on colloidal quantum dots (QDs) represents a potential solar-to-hydrogen (STH) conversion technology to achieve future carbon neutrality. Herein, a self-biased PEC cell consisting of BiVO₄ photoanode and Cu₂ O photocathode both decorated with Zn-doped CuInS₂ (ZCIS) QDs is successfully fabricated. The intrinsic charge dynamics of the photoelectrodes are efficiently optimized via rational engineering of the surface ligands capped on QDs with controllable chain lengths and binding affinities to the metal oxide electrodes. It is demonstrated that the short-chain monodentate 1-dodecanethiol ligands are beneficial to ZCIS QDs for suppressing charge recombination, which enables the construction of tight heterojunction with coupled metal oxide electrodes, leading to effective photo-induced charge transfer/injection for enhanced PEC performance. The QD decorated BiVO₄ and Cu₂ O photoelectrodes in pairs demonstrate a self-biased PEC water splitting process, delivering an STH efficiency of 0.65% with excellent stability under AM 1.5 G one-sun illumination. The results highlight the significance of synergistic ligand and heterojunction engineering to build highly efficient and robust QDs-based PEC devices for self-biased solar water splitting.

Keywords: colloidal quantum dots; heterojunctions; ligand engineering; self-biased photoelectrochemical cells; solar energy conversion.

Abstract

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