Unveiling the influence of SmFeO3-TiO2 nanocomposites as high performance photoanodes of dye-sensitized solar cells

Abstract

Dye-sensitized solar cells (DSSCs) with boosted performances were obtained with a tri-layered photoanode structure containing compact, mesoporous plus light scattering TiO2 films. Furthermore, synthesis of SmFeO3 inorganic perovskite nanocrystalline material was accomplished via the sol-gel process which was then used to prepare diverse (0–2.5%) SmFeO3/TiO2 nanocomposite films as photoanodes of DSSCs. All materials including TiO2, SmFeO3 and SmFeO3/TiO2 nanocomposites were characterized using different analysis methods, i.e. SEM images, XRD, EDS, photoluminescence (PL), DRS, FT-IR, UV–Vis spectra as well as dye adsorption. Besides, influence of SmFeO3 nanostructure was unveiled on the performances of fabricated DSSCs. The bandgap values of the TiO2, SmFeO3 were 3.25, 1.75 eV but they were altered in the range of 1.75–3.10 eV for the (0.25–2.5%) SmFeO3 + TiO2 nanocomposites. The photocurrent density–voltage diagrams were attained to measure DSSCs’ performances. It was shown that the champion device contained 0.5% SmFeO3 + TiO2 composite photoelectrode which indicated PCE = 7.06%, JSC = 17.37 mA.cm−2, VOC = 0.77 V, FF = 0.53. As a result, the 0.5% SmFeO3 + TiO2 nanocomposite enhanced the PCE by 2.66 folds (∼60%) compared to that of reference solar cell composed of pure TiO2 with champion PCE = 4.40%, JSC = 12.75 mA.cm−2, VOC = 0.64 V, FF = 0.53. According to electrochemical impedance spectroscopy (EIS) data, among diverse devices, (0.5% SmFeO3 + TiO2) photoelectrode exhibited the lowest RCT2 value of 5.27 Ω.cm−2. In fact, SmFeO3 incorporation into the TiO2 photoanode highly boosted the JSC values of DSSCs compared to that of the device containing pure TiO2 which confirmed addition of SmFeO3 led to greatly enhanced charge transport within the DSSC through declining charge recombination. Therefore, SmFeO3 could be considered as an effective nanostructured perovskite material to fabricate high-performance DSSC devices.