Graphene quantum dots make efficient solar cells
Scientists create a new kind of organic–inorganic hybrid solar cell that exhibits much higher power conversion efficiency compared to the more expensive, silicon-based commercial ones.
They could potentially be useful for making next-generation flexible, low-cost and high-performance solar devices, they say.
The researchers from Saudi Arabia, Taiwan and Hong Kong added various concentrations of graphene quantum dots to solutions of poly (3,4 ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS). They then deposited the mixed solutions on silicon substrate to create the hybrid cells.
The solar cells showed enhanced short-circuit current density and fill factor, measures of quality for solar cells.
An active region in the solar cells, which contains graphene quantum dots that convert ultraviolet light to visible light, contributed to a power conversion efficiency of 13.22% — the highest power conversion efficiency so far achieved.
Ultraviolet light is usually wasted because it cannot penetrate deeper into solar cells. By converting ultraviolet light to visible light, the solar cells could harness additional solar light, the researchers say.
“This technique would be useful for making a wide variety of solution-processed solar cells, including organic solar cells and perovskite solar cells,” says lead researcher Jr-Hau He from King Abdullah Institute of Science and Technology (KAUST), Saudi Arabia.
- Tsai, M-L. et al. Si hybrid solar cells with 13% efficiency via concurrent improvement in optical and electrical properties by employing graphene quantum dots. ACS Nano http://dx.doi.org/10.1021/acsnano.5b05928 (2015).