▎ 摘　　要

We fabricated a novel nanocomposite composed of graphene-La2CrFeW6 perovskite compounds with an organic-inorganic counter electrode based on CdSe, gallic acid, urea and sulfate in dye-sensitized solar cells (DSSCs) by a simple hydrothermal technique. The nanocomposite shows an excellent electro ecatalytic activity with low charge-transfer resistance, due to the synergetic catalytic effects of the graphene sheets and La2CrFeW6 perovskite with organic-inorganic materials. The special structure of this nanocomposite also improves the active sites for reduction of triiodide ions on the counter electrodes. The photo-conversion efficiency of the DSSC fabricated using a gallic-based counter electrode reached a higher value of 10.40% under standard illumination (1 sun, 100 mW cm(-2), AM 1.5), as compared to the traditional Pt electrode (7.49%). The graphene-La2CrFeW6 fabricated with an organic-inorganic based CE was also found to be more efficient than those reported in previous works, in which graphene, produced by various methods, was used as a CE material. Therefore, the present nanocomposite is considered an environmentally friendly, low-cost, and highly efficient CE material for DSSCs. (C) 2021 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi.