Full-spectrum photovoltaic–thermoelectrochemical cogeneration using thin-film solar cells integrated with liquid-state thermocells

Driven by the need for efficient full-spectrum solar utilization and low-grade heat recovery in sustainable energy systems, this work introduces a hybrid system that couples an emerging thin-film photovoltaic device with a liquid-state thermocell for simultaneous photovoltaic and thermoelectrochemical power generation. A comprehensive theoretical framework is established, incorporating major electrochemical and thermal irreversibilities, to evaluate the coupled behavior of both subsystems. Numerical simulations under AM1.5G illumination show that the hybrid system substantially outperforms its photovoltaic-only counterpart, achieving a maximum efficiency of 22.54%, which corresponds to a 6.57% enhancement at 350 K. Parametric analyses further clarify the governing roles of absorber thickness, donor concentration, device temperatures, and thermal coupling coefficients. Optimal performance is obtained when the photovoltaic subunit operates within its electrical best-performance window while the LTC maintains a large temperature differential supported by efficient heat transfer and minimized environmental losses. These findings provide quantitative guidance for the design and optimization of integrated solar energy conversion architectures, demonstrating the potential of coupling thin-film photovoltaic conversion with thermally driven electrochemical power generation for advanced solar cogeneration.