Exploring the influence of Zn2SnO4/ZIF-8 nanocomposite photoelectrodes on boosting efficiency of dye sensitized solar cells

Abstract

It is imperative to develop innovative efficient photoelectrode materials for high-performance dye-sensitized solar cells (DSSCs). In this work, cubic spinel Zn2SnO4 (ZTO)+(5, 10, 15, 20%) zeolite imidazole framework-8 (ZIF-8) nanoparticles were applied as photoanode materials of DSSC devices. The Zn2SnO4 was effectively synthesized in a simple and cost-effective manner by carefully controlling the hydrothermal conditions. The Zn2SnO4/ZIF-8 nanocomposite photoelectrodes were coated over the TiO2 compact layer to decrease charge recombination at the transparent conductive oxide/mesoporous interface. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), photoluminescence (PL), Brunauer–Emmett–Teller (BET) isotherms, Fourier transform infrared spectroscopy (FT-IR) and electrochemical impedance spectroscopy (EIS) analysis methods were used to study the properties of all nanostructured photoanodes. In addition, the effects of Zn2SnO4/ZIF-8 nanocomposites were evaluated on DSSCs performances. The results clearly showed that adding ZIF-8 to Zn2SnO4 improved the photovoltaic performance of the fabricated DSSCs. Furthermore, compared to pure Zn2SnO4 NPs, Zn2SnO4+15% ZIF-8 increased open circuit voltage (VOC) from 0.64 to 0.77 V and short current density (JSC) from 6.89 to 11.27 mA/cm2. The Zn2SnO4+15% ZIF-8 photoanodes increased the power conversion efficiency (PCE) of DSSC by about 195% (from 2.02 to 3.94%) relative to the pure ZTO photoanode. This was due to the fact that the Zn2SnO4+15% ZIF-8 nanocomposite had the quickest electron transport rate, the best electron collecting efficiency, and the greatest charge recombination resistance, all of which are extremely advantageous to improve device efficiency.