Preparation and properties of CdS_0.25Se_0.75/N-GQDs/3D rGO ternary composites

In this paper, CdS_0.25Se_0.75, N-GQDs and 3D rGO are combined to obtain a hexagonal ternary CdS_0.25Se_0.75/N-GQDs/3D rGO, which was employed to improve the photoelectric performance of alloy semiconductor CdSSe. The steady-state photocurrent density of CdS_0.25Se_0.75/N-GQDs/3D rGO reaches 9.4 × 10⁻⁵ A/cm², which is 30 times higher than that of CdS_0.25Se_0.75/N-GQDs and 300 times higher than that of pure CdS_0.25Se_0.75 semiconductors. The electrochemical impedance spectroscopy (EIS) results show that the interface charge transfer resistance of CdS_0.25Se_0.75/N-GQDs/3D rGO is lower than that of CdS_0.25Se_0.75/N-GQDs and CdS_0.25Se_0.75. From the calculated result of Mott–Schottky tests, the carrier density of CdS_0.25Se_0.75/N-GQDs/3D rGO reaches 3.99 × 10²⁰ cm⁻³, which is superior to that of CdS_0.25Se_0.75 (1.85 × 10²⁰ cm⁻³) and CdS_0.25Se_0.75/N-GQDs (3.18 × 10²⁰ cm⁻³). Among them, N-GQDs serve as photosensitizers to improve the light absorption and 3D rGO aerogels serve as electron-transfer substrates for charge separation and transport instead of recombination of electron–hole pairs.