LAUSR

Graphene quantum dots (GQDs), N-doped GQDs (NGQDs) and S, N co-doped GQDs (SNGQDs) were synthesized using hydrothermal methods. All GQDs were attached with carbon-doped ZnO nanorods (C-ZnO NRs) grown on fluorine-doped tin oxide (FTO)-coated glass substrates, for the fabrication of metal-free eco-friendly quantum-dot-sensitized solar cells (QDSSCs). SNGQD-decorated nanorod-based solar cells demonstrated maximum open circuit voltage ($$V_{\mathrm{OC}}\sim 360$$VOC∼360 mV), short circuit current ($$J_{\mathrm{SC}}\sim 1.84$$JSC∼1.84 mA $$\hbox {cm}^{-2})$$cm-2) and power conversion efficiency ( $$\eta \sim 0.293$$η∼0.293%) compared to other devices.