Ultrafast and efficient photothermal conversion for sunlight-driven thermal-electric system

Abstract

Thermoelectric battery is effective in converting thermoelectricity based on Seebeck effect. As an all-solid-state energy conversion model, this battery is highly significant in improving the utilization of solar energy using a clean and noiseless process. However, efficient photothermal conversion and temperature difference control are the key challenges in enhancing solar-thermal-electric conversion. Herein, we constructed a novel sunlight-driven thermoelectric system with temperature difference control characteristic. In which the light-driven phase change heat storage material (PCHSM) was used as the hot side, and the phase change cool storage material (PCCSM) as the cold side. Ultrafast photothermal conversion of the PCHSM was achieved through the nonradiative decay of the excited state, which was revealed by means of femtosecond transient absorption technique. Solar radiation was efficiently utilized as shown by the excellent visible light absorption, ultrafast photothermal transformation, and phase change heat storage characteristics of the PCHSM. The PCCSM with high phase change cool storage performance could provide enough cold energy to maintain the cold-side temperature. Temperature gradient was controlled using the cold-side and hot-side materials based on the phase-change temperature control characteristics.