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

Comprehensive Summary 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.