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.