Dye-sensitized solar cells with efficiencies exceeding 10% engineered based on La2MnTiO6 double perovskite and MOF-derived Cr2O3/C nanocomposites in bi-layered photoanodes

Abstract

To improve the photoanode performance of dye-sensitized solar cells (DSSCs), developing double-layered photoanodes have been proposed consisting of La2MnTiO6 + Cr2O3/C nanocomposites in diverse ratios to find the optimal amount. The (x%) La2MnTiO6 + (y%) Cr2O3/C nanocomposites were coated as the overlayer and TiO2 nanoparticles as the underlayer in photoelectrodes. La2MnTiO6, Cr2O3/C, and La2MnTiO6 + Cr2O3/C nanocomposites have been synthesized using sol-gel method, MIL-101(Cr), and hydrothermal method, respectively, and applied as effective light-absorbing photoelectrode layers on the top of TiO2 photoanode in DSSC and compared to TiO2 monolayer film. Numerous analyses and photocurrent density-voltage (J-V) plots were taken to evaluate nanocomposites characteristics. Because of superior light absorbing as well as light-scattering abilities, high amount of dye loading, porous surfaces with high electron transport capacity, and less electron-hole recombination at the 70%La2MnTiO6 + 30%Cr2O3/C film/TiO2/electrolyte interface, the champion cell based on TiO2/20% (70%La2MnTiO6 + 30%Cr2O3/C) photoanode showed a 2.19-fold higher power conversion efficiency (PCE = 9.00%) than the traditional TiO2 monolayer based photoanode (PCE = 4.11%). The amount of the 70%La2MnTiO6 + 30%Cr2O3/C composite loading in the second layer film on the TiO2 layer was also varied in photoanodes. By optimizing the percentage of composite loaded in the second layer, champion device with optimal TiO2/15% (70%La2MnTiO6 + 30%Cr2O3/C) nanocomposite unveiled the largest PCE = 10.07%, enhancing the PCE by about 11.8% and 145% in comparison with TiO2/20% (70%La2MnTiO6 + 30%Cr2O3/C) and monolayer TiO2 photoanodes, respectively.