Efficiency improvement of luminescent solar concentrators using upconversion nitrogen-doped graphene quantum dots

Luminescent solar concentrators (LSCs) incorporated with a large number of luminophores are used as an important trend which increases the efficiency of solar cells by concentrating solar energy onto photovoltaics (PVs). However, the main loss in LSC-PV devises results from the incomplete utilization of the solar spectrum. Extending the spectral absorption from UV-Vis into near-infrared (NIR) by means of upconversion particles, reduces the transmission loss of sub-band-gap photons with improved energy alignment. In this study, a new nitrogen-doped graphene quantum dot (N-GQD) possessing upconversion photoluminescence (UCPL), single color emission in UV-Vis-NIR region has been introduced. Large stocks shift of newly synthesized GQDs that is more than 100 nm reduces reabsorption losses significantly. Photoluminescence (PL) quantum yield is measured to be 65%. Under solar radiation, the optical features of N-GQDs as absorbers/emitters in polymethyl methacrylate (PMMA) is studied. Our results demonstrate that GQDs-LSC attached to a perovskite solar cell could enhance efficiency. The GQDs-LSCs reaches the power conversion efficiency (PCE) more than 4.3 times of PMMA-PV devise. Although the use of N-GQDs hybrid in LSCs for its upconversion feature is at an initial research step, the results prove that it provides a promising way for low cost and nonhazardous solar energy.