Carbon dot–based tandem luminescent solar concentrator

Luminescent solar concentrators (LSCs) are light-management devices, which are used for harvesting and concentrating of solar light from a large area to their edges. Being semitransparent devices, LSCs keep a great promise for future utilization in glass walls of urban buildings as environmentally friendly photovoltaic power plants. Development of cheap and eco-safe materials, extension of the LSC operation range as well as the enhancement of the optical efficiency are the key challenges, which need to be solved in order to transform energetically passive buildings into self-sustainable units. Here, a large area (64 cm2) tandem LSC fabricated from entirely eco-friendly highly emissive blue, green, and red carbon dots is demonstrated, with an internal optical quantum efficiency of 23.6% and an external optical quantum efficiency of 2.3%, while maintaining a high transparency across the visible spectrum. This opens up a new direction for application of carbon dots for advanced solar light harvesting technologies.