Broadband and strong visible-light-absorbing cuprous sensitizers for boosting photosynthesis.

Abstract

Rational construction of broadband and strong visible-light-absorbing (BSVLA) earth-abundant complexes is of great importance for efficient and sustainable solar energy utilization. Herein, we explore a universal Cu(I) center to couple with multiple strong visible-light-absorbing antennas to break the energy level limitations of the current noble-metal complexes, resulting in the BSVLA nonprecious complex (<b>Cu-3</b>). Systematic investigations demonstrate that double "ping-pong" energy-transfer processes in <b>Cu-3</b> involving resonance energy transfer and Dexter mechanism enable a BSVLA between 430 and 620 nm and an antenna-localized long-lived triplet state for efficient intermolecular electron/energy transfer. Impressively, <b>Cu-3</b> exhibited an outstanding performance for both energy- and electron-transfer reactions. Pseudo-first-order rate constant of photooxidation of 1,5-dihydroxynaphthalene with <b>Cu-3</b> can achieve a record value of 190.8 × 10^-³ min^-¹ among the molecular catalytic systems, over 30 times higher than that with a noble-metal photosensitizer (PS) [Ru(bpy)₃]²⁺. These findings pave the way to develop BSVLA earth-abundant PSs for boosting photosynthesis.