Promoting charge separation in a composite of δ-CsPbI3 and covalent organic frameworks

Abstract

In contrast to black CsPbI₃ perovskite, yellow non-perovskite δ-CsPbI₃ is thermodynamically more stable at room temperature and in humid conditions, but exhibits negligible photocatalytic activity due to its severe recombination of photogenerated charges. Here, we report a strategy to promote the charge separation in a composite of δ-CsPbI₃ and TaPt-TP-COF by targeted deposition of metallic Pt particles on δ-CsPbI₃. The photoluminescence band stemming from the recombination of excitons in δ-CsPbI₃ is significantly quenched when attached to TaPt-TP-COF. The δ-CsPbI₃, Pt@δ-CsPbI₃ and δ-CsPbI₃@TaPt-TP-COF exhibit negligible photocatalytic hydrogen evolution (PHE) from water in the presence of a triethanolamine electron donor, whereas the Pt@δ-CsPbI₃@TaPt-TP-COF demonstrates a remarkable improvement in PHE rate. In addition, the Pt@δ-CsPbI₃@TaPt-TP-COF also presents high stability in solution conditions.