Photovoltaic-thermoelectric (PV-TE) conversion is a promising method for power generation, which converts solar power into electricity using the photovoltaic (PV) effect of solar cells and simultaneously generates electricity by the Seebeck effect of the thermoelectric (TE) device based on the waste heat of solar cells. Here, the power generation of the PV-TE device at night is experimentally demonstrated using radiative cooling that harnesses th. Photovoltaic-thermoelectric (PV-TE) conversion is a promising method for power generation, which converts solar power into electricity using the photovoltaic (PV) effect of solar cells and simultaneously generates electricity by the Seebeck effect of the thermoelectric (TE) device based on the waste heat of solar cells. Here, the power generation of the PV-TE device at night is experimentally demonstrated using radiative cooling that harnesses the cold of the universe directly. The PV-TE device is constructed by attaching a TE device on the bottom of the glass-covered PV module, with a heat sink stuck on the opposite side of the TE device. The open-circuit voltage of the TE device integrated into the PV-TE device was measured to be approximately 9 mV, indicating that the PV-TE device can definitely generate electricity from the darkness. Moreover, a new configuration of the PV-TE device for continuous power generation in the day and night is conceptually proposed for further consideration. In summary, this work proves the possibility of the PV-TE device for nighttime power generation, which could provide an alternative pathway for a wide range of nighttime and all-day power-consumed applications, such as lower power sensors and monitors.••••Nighttime power generation of the PV-TE device was experimentally demonstrated.••An average output voltage of the PV-TE device was measured as 9 mV in night.••A new configuration of the PV-TE device for continuous power generation is proposed.••This work provides an alternative pathway for nighttime and all-day applications.Radiative coolingThermoelectric generatorNighttime power generationPV-TEExploring efficient and clean methods for power generation is a meaningful project since the massive use of fossil fuel for power generation has already brought serious environmental problems, such as the greenhouse effect. Photovoltaic (PV) conversion is exactly one of the clean methods for power generation, which converts solar photons with high energy levels into electricity directly. Besides, thermoelectric (TE) conversion can also generate electricity using a clean way by converting heat energy into electricity directly based on the Seebeck effect of the TE generator. Currently, many researchers have focused on the topic of photovoltaic-thermoelectric (PV-TE) hybrid conversion by integrating PV and TE effect into a single device [,, ]. PV-TE conversion is a promising power generation method that converts solar photons into electricity via the PV effect of solar cells and simultaneously generates electricity using the TE effect based on the waste heat of solar cells, which improves the efficiency of the power generation.There are numerous previously reported works on the topic of the PV-TE hybrid conversion ranging from materials sciences to engineering applications. Sark conducted a performance analysis of PV-TE hybrid modules by attaching TE generators to the back of the PV modules directly and numerically revealed that the total power generation efficiency can be improved by 8–23%. Li et al. [7,8. 2.1. Concept descriptionThe schematic of the PV-TE device for all-day power generation is presented in Fig. 1. In the daytime, the PV module absorbs solar photons and partly converts them to electricity, while the remaining absorbed solar power is dissipated into heat and can be further used to generate electricity by the TE device using the Seebeck effect. In the nighttime, the temperature of the PV module drops to be lower than the temperature of the ground-faced side of the TE device due to the existence of radiative cooling. Thus, the heat is extracted from the ambient environment by convection and conduction heat transfer to the bottom of the TE device and finally pumped to the cold universe using radiative cooling, with electricity output generated by the TE device.2.2. Description of the PV−TE device and experimental set-upThe PV-TE device, as shown in Fig. 2(a), is constructed by attaching a commercial TE device (TEG1-127-1.4-1.0) to the bottom of the PV module. To enhance the heat transfer process at the bottom surface of the TE device, a heat sink is fixed on the bottom surface of the TE device. All contact surfaces are connected using the thermal conductive glue (HY510, Halnziye). The PV.
