Subtly regulating layered tin chalcogenide frameworks for optimized photo-induced carrier separation

Abstract

Layered tin chalcogenide frameworks (LTCFs) have attracted great attention due to the stable structure and effective integration of porosity with semiconducting properties. Though they have a much suitable band gap and rich structures, the significance of LTCFs in photoelectrochemical applications and “structure–property” studies is highly undervalued. Herein, we report an example of “structure–property” correlations in photoelectrochemical applications using three subtly regulated LTCFs that show nuances in the intralayer architecture and packing mode of layers. Of particular interest is the huge difference in their photoelectric responses despite the same secondary building block (Sn₃S₄), linkers (shared Sn₂S₂) and 2D honeycomb-type topology. In particular, LTCF-3 has the highest photocurrent density, which is nearly five times that of LTCF-2. Enhanced photoelectric response for LTCF-3 was attributed to the elongated distance between adjacent clusters, which dramatically decreased the recombination of photo-induced carriers. This deduction was supported by precise structure analysis, UV-vis absorption spectroscopy and theoretical calculations.