Considering global climate change concerns, issues related to the energy crisis and technologies reliant on non-fossil renewable energy sources are in high demand. Solar energy emerges as one of the alternatives among all renewable energy resources due to its economic viability and environmental sustainability. There are various types of solar photovoltaic (PV) technologies available for commercial applications, such as organic solar cells, silicon-based solar cells, dye-sensitized solar cells, and perovskite solar cells. Notably, one of the drawbacks of PV devices is their inability to generate power at night or during cloudy days (i.e., low-light conditions). One solution to this problem is to provide backup to the PV devices, such as batteries or energy storage packs. Another less explored alternative backup is the application of long persistent luminescence (LPL) materials as a secondary light source or down shifter. LPL materials can provide an afterglow that can last for hours which can be harvested by PV devices for power generation under low-light conditions. This short overview article discusses the fundamental mechanisms of LPL materials and the feasibility and challenges of integrating LPL materials into PV, which is hoped can provide useful insights for future research directions.
Supercapacitors (SCs), including electric double-layer capacitors (EDLCs), pseudocapacitors, and hybrid capacitors, are esteemed for their high power density and attractive features such as robust safety, fast charging, low maintenance, and prolonged cycling lifespan, sparking significant interest. Carbon quantum dots (CQDs) are fluorescent nanomaterials with small size, broad excitation spectrum, stable fluorescence, and adjustable emission wavelengths. They are widely used in optoelectronics, medical diagnostics, and energy storage due to their biocompatibility, low toxicity, rich surface functional groups, abundant electron-hole pairs, large specific surface area, and tunable heteroatom doping. In this short review, we briefly discussed the advantages and disadvantages of bottom-up and top-down of CQD synthesis methods. The arc-discharge technique, laser ablation technique, plasma treatment, ultrasound synthesis technique, electrochemical technique, chemical exfoliation, and combustion are among the initial top-down approaches. The subsequent section delineates waste-derived and bottom-up methods, encompassing microwave synthesis, hydrothermal synthesis, thermal pyrolysis, and the metal-organic framework template-assisted technique. In addition, this short review focuses on the operational mechanism of supercapacitors, their properties, and the utilization of CQDs in supercapacitors.