Fig. 4
a The I–V characteristic curves of the UV photodetectors under dark and UV light irradiation decorated with/without GQDs (inset: the magnified I–V characteristic curves of the UV photodetectors). b The I–V characteristic curves illuminated with UV light of different incident power densities (mW/cm2). c The photoresponse at different incident light power densities (mW/cm2). d The responsivity (red) and detectivity (blue) as a function of the incident light power density, respectively