Synergistic solar electricity-water generation through an integration of semitransparent solar cells and multistage interfacial desalination

Energy shortage and freshwater scarcity are critical challenges for the sustainable development of the society. The photovoltaic-thermal (PVT) hybrid system offers a promising strategy by harnessing solar energy for electricity and water cogeneration. However, existing systems suffer from relatively low efficiency due to incomplete solar spectrum utilization. To address this, we propose a novel PVT integrated system that combines semi-transparent solar cells and multistage interfacial stills to maximize solar spectrum utilization, allowing for efficient electricity and freshwater co-production. Experimental results demonstrate a record-high solar-to-vapor efficiency of 210 % with a production rate of 3.17 L m⁻² h⁻¹ under one-sun, while maintaining an uncompromised electrical efficiency of 19.57 %. Furthermore, we employ a verified theoretical framework to provide optimized strategies for concurrent enhancement of electricity-water production, by improving internal heat and mass transfer and effectively reducing the thickness of the interstage air gap. Moreover, we introduce a non-contact model for system structure optimization proposed to match the high transmittance of solar cells. This work realizes full solar spectrum utilization to cogenerate electricity and freshwater, offering optimized strategies from the thermal perspective for future research.