Enhancement in photocurrent conversion efficiency via recrystallization of zinc tin hydroxide nanostructures

Abstract

Herein, the synthesis of cubic phase zinc tin hydroxide is reported by the hydrolysis assisted co-precipitation method followed by calcination in 150–850 °C. The recrystallization of zinc tin hydroxide (ZnSn(OH)6) to zinc tin oxide (Zn2SnO4) phase is observed with the intermediate amorphous phase (ZnSnO3) by increasing the calcination temperature. Increase in calcination temperature also causes the partial alteration in the cubic morphology and diminution in average particle size. The M-O-M and M-O vibration modes have distinct peaks in the FT-IR spectra below 1500 cm−1. Four Raman active vibration modes in ZnSn(OH)6 and two Raman active vibration modes in Zn2SnO4 phase are observed, while no Raman active mode is present in intermediate amorphous ZnSnO3. Chemical states of various elements and compositions are examined by X-ray photoelectron spectroscopy. The ZnSnO3 electrodes has the lowest charge transfer resistance and higher lifetime of the photogenerated charge carriers. Photoelectrochemical measurements rendered enhanced photocurrent density for ZnSnO3 and Zn2SnO4 phases, which is approximate 85 and 50 times higher as compared to ZnSn(OH)6 based photoelectrode, respectively. Due to crystalline nature, the Zn2SnO4 phase has better photo-stability. © 2022 Elsevier B.V.