Enhanced photothermal conversion of tannic acid-grafted Cu2-xS/MoS2 Heterostructures by ag doping

Converting solar energy to electricity in smart windows is challenging, as it requires maintaining high visible-light transmittance while achieving efficient solar-to-heat and heat-to-electricity conversion. Here, we fabricate a transparent photothermal film composed of a tannic acid (TA)-grafted Cu2-xS/MoS2 composite with highly dispersed Ag doping. Under 808 nm laser irradiation, the 5% Ag-doped Cu2-xS/TA-MoS2 freestanding transparent membrane yields a temperature rise 8.3 °C higher than that of the undoped control, while maintaining a high visible-light transmittance of over 84%. Experimental and theoretical analyses reveal that Ag doping optimizes the hole carrier concentration to strengthen localized surface plasmon resonance, and tunes the heterojunction band alignment to promote heat generation via non-radiative relaxation. Furthermore, the membrane generates an output voltage of 65.9 mV under 1-sun illumination. This work provides an effective strategy for constructing high-performance, transparent photothermal materials for energy-saving building glazing.