Influence of structural and chemical properties on electron transport in mesoporous ZnO-based dye-sensitized solar cell

Abstract

Two chemical bath deposition (CBD) solutions were prepared at two different temperatures of 60 and 80 °C for dye-sensitized solar cell (DSSC) application. The deposition time was varied from 12, 18, and 24 h. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis confirmed a transformation of hydrozincite into ZnO after calcined at 300 °C. The flower-like structure was observed by scanning electron microscopy (SEM) analysis. The ZnO photoanode deposited at 80 °C for 24 h showed the highest incident photon to charge carrier efficiency (IPCE) value of 5.25 %. The power conversion efficiency, η increased from 1.81 to 2.45 % for the photoanode deposited at 60 and 80 °C, respectively. The effective electron lifetimes, τeff of 6.36 ms was measured as much shorter than the TiO2-based DSSC (τeff of 25 to 160 ms). The effective electron diffusion coefficient, Deff, increased from 1.7 × 10−3 to 4.7 × 10−3 cm2.s−1 when the deposition temperature increases from 60 to 80 °C. Effective rate constant for recombination, keff of 157 s−1 was calculated for both samples. The results and analysis of the film’s surface structure, morphology, electron diffusion, and recombination inside the mesoporous ZnO photoanode proved the applicability of ZnO for the DSSC’s application.