Improvement of the current generation in silicon solar cells by utilizing graphene quantum dot as spectral converter

•Graphene quantum dots can serve as UV to Visible photon convertors.•A transparent GQD filled luminescent down-shifting layer applied on Si solar cell.•A 5.14% relative enhancement in the JSC of mc-Si solar cell obtained.•A 6.82% relative enhancement in the JSC of c-Si solar cell obtained. This paper deals with a luminescent layer applied on a commercial Silicon (Si) solar cell by spin coating of an aqueous solution of graphene quantum dots (GQDs), synthesized by the hydrothermal method at 200 °C for 24 h. The GQDs layer, acted as a luminescent down-shifting (LDS) layer, causes a relative enhancement in the short circuit current density (JSC) of mc-Si and c-Si solar cells up to 5.14% and 6.82%, respectively. Remarkable relative enhancements in JSC under UV illumination showed that the LDS layer increases the JSC by downshifting effect; Diffuse reflectance spectroscopy (DRS) of the solar cells with and without the LDS layers showed that the GQD filled LDS layers do not have a considerable effect on the light reflection from the Si solar cell to affect the JSC.