In this perspective, we focus on a new type of quantum dots, graphene quantum dots (GQDs). Due to quantum confinement and edge effects, GQDs have presented extraordinary properties, attracting extensive attention from scientists in the fields of chemistry, physics, materials, biology, and other interdisciplinary sciences. Herein, we summarize the significant advances achieved by us and other groups in the past few years on both the experimental and theoretical fronts. Synthetic strategies, unique optical and electronic properties, and the promise of GQDs in energy-related devices, such as photovoltaic devices, fuel cells, and light-emitting diodes, are systematically discussed.

The depletion of fossil fuels and the corresponding environmental concerns require the development of new kinds of green energy. We herein present a new type of highly efficient electric generation by the traditional polyelectrolyte membrane of poly(4-styrensulfonic acid) (PSSA) with moisture. This polymer moist-electric generator (PMEG) with a piece of 1 cm² PSSA membrane can offer an open-circuit-voltage of up to ∼0.8 V and a short-circuit-current density of ∼0.1 mA cm⁻², which is sufficient to power up many electronic devices. Flexible power supply devices made of PSSA membranes are designed and fabricated for harvesting the energy from human breath and some other real-life conditions. The experimental demonstration and theoretical modeling reveal that the moisture-induced directional movement of protons within the PSSA membrane led to the generation of electric power. This work opens a novel perspective for the traditional polyelectrolyte membrane and offers an extremely simple method for energy conversion of practical importance.