Computation-based regulation of excitonic effects in donor-acceptor covalent organic frameworks for enhanced photocatalysis

Yunyang Qian; Yulan Han; Xiyuan Zhang; Ge Yang; Guozhen Zhang; Hai-Long Jiang

doi:10.1038/s41467-023-38884-w

Computation-based regulation of excitonic effects in donor-acceptor covalent organic frameworks for enhanced photocatalysis

Nat Commun. 2023 May 29;14(1):3083. doi: 10.1038/s41467-023-38884-w.

Authors

Yunyang Qian^#¹, Yulan Han^#², Xiyuan Zhang¹, Ge Yang¹, Guozhen Zhang², Hai-Long Jiang³

Affiliations

¹ Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
² Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
³ Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China. jianglab@ustc.edu.cn.

^# Contributed equally.

Abstract

The strong excitonic effects widely exist in polymer-semiconductors and the large exciton binding energy (E_b) seriously limits their photocatalysis. Herein, density functional theory (DFT) calculations are conducted to assess band alignment and charge transfer feature of potential donor-acceptor (D-A) covalent organic frameworks (COFs), using 1,3,5-tris(4-aminophenyl)triazine (TAPT) or 1,3,5-tris(4-aminophenyl)benzene (TAPB) as acceptors and tereph-thaldehydes functionalized diverse groups as donors. Given the discernable D-A interaction strengths in the D-A pairs, their E_b can be systematically regulated with minimum E_b in TAPT-OMe. Guided by these results, the corresponding D-A COFs are synthesized, where TAPT-OMe-COF possesses the best activity in photocatalytic H₂ production and the activity trend of other COFs is associated with that of calculated E_b for the D-A pairs. In addition, further alkyne cycloaddition for the imine linkage in the COFs greatly improves the stability and the resulting TAPT-OMe-alkyne-COF with a substantially smaller E_b exhibits ~20 times higher activity than the parent COF.