Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
Nat Commun. 2023 May 29;14(1):3083. doi: 10.1038/s41467-023-38884-w.
The strong excitonic effects widely exist in polymer-semiconductors and the large exciton binding energy (E) 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 can be systematically regulated with minimum E in TAPT-OMe. Guided by these results, the corresponding D-A COFs are synthesized, where TAPT-OMe-COF possesses the best activity in photocatalytic H production and the activity trend of other COFs is associated with that of calculated E 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 exhibits ~20 times higher activity than the parent COF.
强激子效广泛存在于聚合物半导体中，大激子结合能 (E) 严重限制了它们的光催化性能。在此，使用密度泛函理论 (DFT) 计算评估了潜在给体-受体 (D-A) 共价有机骨架 (COF) 的能带排列和电荷转移特性，其中 1,3,5-三(4-氨基苯基)三嗪 (TAPT) 或 1,3,5-三(4-氨基苯基)苯 (TAPB) 用作受体，而对苯二甲醛官能化的不同基团用作供体。鉴于 D-A 对中存在明显的 D-A 相互作用强度，可以系统地调节其 E，使 TAPT-OMe 中的 E 最小化。根据这些结果，合成了相应的 D-A COF，其中 TAPT-OMe-COF 在光催化产氢中表现出最佳的活性，而其他 COF 的活性趋势与计算得出的 D-A 对的 E 相关。此外，进一步对 COF 中的亚胺键进行炔烃环加成反应可大大提高稳定性，所得 TAPT-OMe-炔烃-COF 的 E 显著减小，其活性比母体 COF 高约 20 倍。
