A metal ion and electrolyte free twin electrode photocapacitor possessing ultrafast charging capability†

Abstract

The advancement in the field of solar energy conversion devices has led to the development of both energy generation and energy storage technologies. However, a hybrid device capable of both generation and storage is still in its infancy. In this work, a multi-layered twin electrode photocapacitor has been developed which is free of metal ions and electrolyte. The device was composed of an active layer of CdSe quantum dots (QD) embedded in a polymer matrix and sandwiched between multi-layered stacking (MLS) of rGO and TiO₂. An ultrafast charging time of 3–5 s was achieved under 1 sun illumination with a discharge time of over 500 s under load. An optimized capacitance of 307.4 mF g⁻¹ was obtained under load while 6022 mF g⁻¹ capacitance was obtained under load and LED illumination with ∼88% retention capacity after 200 cycles. Additionally, the device was also able to partially harness low intensity radiation (∼60 lux).