Toward full-spectrum solar energy utilization via synergistic coupling of perovskite solar cells and liquid-state thermocells

Perovskite solar cells efficiently convert photons near the semiconductor bandgap into electricity, while sub-bandgap and excess-energy photons are predominantly dissipated as heat, resulting in substantial spectral and thermal losses. To address this limitation and harvest full-spectrum solar energy, an energy cascaded utilization system integrating a methylammonium lead triiodide solar cell, a solar selective absorber, and a thermocell is proposed and theoretically investigated. A coupled electro-thermal model is developed to describe the interaction between the subsystems, explicitly accounting for the area ratio, iterative energy balance for determining thermocell electrode temperatures, and irreversible losses in both components. Under standard air mass 1.5 global irradiation, the integrated system achieves a peak energy conversion efficiency of 20.0% at 333.15 K, delivering a 10.5% efficiency enhancement by effectively recycling low-grade thermal energy compared with a standalone solar cell. Parametric analyses reveal that the thermal sensitivity of the solar cell primarily governs the overall system performance, while the thermocell provides an efficiency gain through optimized thermal coupling. Lower solar cell and heat sink temperatures, reduced thermal leakage, enhanced heat conduction, and appropriate the thickness of the perovskite active layer and the thermocell are identified as key design factors for maximizing hybrid efficiency. This work establishes a systematic modeling framework and provides design-oriented insights for perovskite-based coupled systems, highlighting their potential for efficient solar full-spectrum utilization and waste heat recovery.