Dual-phase zinc selenide in situ encapsulated into size-reduced ZIF-8 derived selenium and nitrogen co-doped porous carbon for efficient triiodide reduction reaction

Abstract

Constructing cost-effective and robust counter electrodes (CEs) without noble metals remains a challenge for the commercialization of current dye-sensitized solar cells (DSSCs). In this study, we focus on the built-in zinc element into the zeolitic imidazolate framework (ZIF-8) to construct a composite of dual-phase zinc selenide (ZnSe) encapsulated by the size-reduced ZIF-derived Se/N-doped carbon (PS N-C_SR) using a post-selenization procedure. Benefitting from the enhanced synergy and charge transfer between the small-sized doped carbon skeleton and well-dispersed dual-phase ZnSe active sites, the resultant PS N-C_SR exhibited superior catalytic activity and durability to the triiodide reduction reaction (IRR). The devices that utilize PS N-C_SR CE achieved a high power conversion efficiency of 8.48%, surpassing that of Pt (7.20%). It is expected that this work will provide an extensible pathway for designing efficient hybrid electrocatalysts with beneficial structures containing transition metal compounds based on ZIF analogs.