Adaptive Donor-Acceptor Modulation in Conjugated Polymers for Sustainable Solar-Driven Water-Electricity Cogeneration

Abstract

Organic conjugated polymers (CPs) enable solar-driven interfacial evaporation through photothermal conversion, yet remain hindered by narrow solar absorption spectra and suboptimal energy conversion efficiency. Herein, we developed an intramolecular charge transfer strategy via donor-acceptor modulation to enhance solar absorption and photothermal conversion capabilities of D-A type CPs. Theory calculations confirm that regulating donor building blocks with varying electron densities tunes the intramolecular charge-transfer dynamics, thereby facilitating near-infrared spectral absorption and non-radiative relaxation. Consequently, BBT-An powder, featuring the donor with the highest electron density, exhibits broad absorption across full solar spectrum with the highest photothermal conversion efficiency under solar irradiation. Moreover, the evaporation rate of BBT-An evaporator attains a water evaporation rate of 1.65 kg·m⁻²·h⁻¹ with 94.19% of water evaporation efficiency under 1 sun. Even when integrated with a thermoelectric module, the hybrid system maintains a stable open-circuit voltage of 159.3 mV under 1-sun illumination with minimal evaporation loss. This work establishes a molecular design strategy for high-efficiency organic solar-thermal materials, advancing their applicability in photothermal technologies through broadband absorption and enhanced energy conversion.

Keywords

Donor–acceptor structure / Charge transfer / Solar absorption / Non-radiative transition / Photothermal conversion / Water-electricity cogeneration

RIGHTS & PERMISSIONS

2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH