Doped Graphene Quantum Dots Modified Zn0.9Cd0.1Se for Improved Photoelectric Properties

S-graphene quantum dots (GQDs), N-GQDs, P-GQDs, and Cl-GQDs are prepared by a solution chemistry method and further incorporated with Zn_xCd_1−xSe by one-step hydrothermal method. In the previous study, Zn_xCd_1−xSe reached the optimal photoelectric performances at the Zn/Cd ratio of 0.9:0.1, so the Zn_0.9Cd_0.1Se were combined with doped GQDs (D-GQDs) to form Zn_0.9Cd_0.1Se/doped-GQDs. The influence of GQDs doped with different elements on the photoelectric properties of Zn_0.9Cd_0.1Se composites is discussed. Compared with pristine Zn_0.9Cd_0.1Se, Zn_0.9Cd_0.1Se/Cl-GQDs, and Zn_0.9Cd_0.1Se/P-GQDs can improve the photocurrent response and current intensity, therein, Zn_0.9Cd_0.1Se/Cl-GQDs reaches the lowest interfacial charge transfer resistance and the highest photocurrent response of 5.48 × 10⁻⁶ A cm⁻². Mott–Schottky analysis shows that the fitting slope of Zn_0.9Cd_0.1Se/Cl-GQDs composites is significantly lower than that of Zn_0.9Cd_0.1Se/GQDs with other doped elements. The results indicate that Zn_0.9Cd_0.1Se/Cl-GQDs composites has the largest carrier density, which is beneficial to charge conduction.