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In this paper, CdS0.25Se0.75, N-GQDs and 3D rGO are combined to obtain a hexagonal ternary CdS0.25Se0.75/N-GQDs/3D rGO, which was employed to improve the photoelectric performance of alloy semiconductor CdSSe. The steady-state photocurrent density of CdS0.25Se0.75/N-GQDs/3D rGO reaches 9.4 × 10−5 A/cm2, which is 30 times higher than that of CdS0.25Se0.75/N-GQDs and 300 times higher than that of pure CdS0.25Se0.75 semiconductors. The electrochemical impedance spectroscopy (EIS) results show that the interface charge transfer resistance of CdS0.25Se0.75/N-GQDs/3D rGO is lower than that of CdS0.25Se0.75/N-GQDs and CdS0.25Se0.75. From the calculated result of Mott–Schottky tests, the carrier density of CdS0.25Se0.75/N-GQDs/3D rGO reaches 3.99 × 1020 cm−3, which is superior to that of CdS0.25Se0.75 (1.85 × 1020 cm−3) and CdS0.25Se0.75/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. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was reduced by thermal annealing treatment of annealing temperature and annealing time to prepare reduced GO (RGO) in air/nitrogen atmosphere. The produced RGO was characterized by X-ray diffraction, ultraviolet-visible absorption spectroscopy, Raman spectrometer and Fourier Transform Infrared Spectrometer. The results show the change of oxygen contents and bonding structure, which reveals the temperature dependence reduction. To investigate changes in carbon basal plane of RGO, the electrochemical behavior of RGO annealed with varying temperature and time was evaluated by three-electrode cyclic voltammetry. The remarkable increase in both the current density and the electrochemical area can be seen for RGO annealed at the temperature of 400 °C and the time of 5 min in nitrogen. [ABSTRACT FROM AUTHOR]

CdSSe/graphene composites were prepared by a solvothermal process using cadmium acetate as Cd precursors, sulfourea as S precursors and selenosulfate as Se precursors. The value of x could be adjusted by controlling the molar ratio of S and Se precursors, and the products were characterized by X-ray diffraction, scanning electron microscope and further evaluated by transient photocurrent responses and electrochemical impedance spectroscopy. Compared with pure CdSSe, CdSSe/graphene composites exhibit enhanced photocurrent response and decreased electron-transfer resistance due to the presence of graphene. The photocurrent of CdSSe/graphene increases with the increase of the Se/S ratio and reaches the maximum at the Se/S ratio of 0.75:0.25. The effect of graphene on the photocurrent response was explored and a higher photocurrent density can be observed for 1 % CdSSe/graphene. [ABSTRACT FROM AUTHOR]