Thermo-photovoltaic generator with thermal energy storage using Schottky heterojunction of RGO-PCM nanocomposite on SiNWs on silicon chip

The thermo-photovoltaic (TPV) systems have garnered significant interest owing to its versatile applications, particularly in the direct conversion of thermal energy into electricity. In the present work, by incorporating thermal energy storage system into the thermal photodiode framework, our approach contributes to the development of more efficient and sustainable energy conversion technologies. The reduced graphene oxide (RGO) was combined with PCM and a heterojunction was made on silicon nanowires (SiNWs) on Si chip, which provided a consistent photovoltage and photocurrent for a longer duration under IR radiation. The thermal cycling of the RGO-PCM on SiNWs on the Si chip device was illustrated. When, the developed heterojunction was exposed with IR radiation, the temperature was increased to nearly 59 degrees C in 8 min, generated a photovoltage of 254 mV and a photocurrent of 16 mu A which continued to produce same power for further 10 to 15 min even if IR radiation was switched off, due to the stored thermal energy in the composite material. After this, the voltage slowly decayed. In contrary to this, in the case of just pristine graphene, a very less photovoltage was generated which returned to the baseline within 11 to 20 s when the IR radiation was switched off. This effect clearly demonstrated that RGO-PCM on SiNWs on Si chip device, forming a Schottky heterojunction diode, has the capability of storing thermal energy. It not only stores heat in the nanocomposite of graphene and paraffin wax (PCM) but also provides electrical energy for an extended period. The time for storing thermal energy and converting it into electricity for a prolonged duration can be customized by varying the compositions of the composite. Additionally, the thermal capacity can be increased by optimizing the thickness and area of the layer. Hence, this work opens up new possibilities for utilizing thermal energy to generate electric power for an extended period, providing a valuable solution for scenarios where conventional energy sources may be intermittent or unavailable.