Preparation and photoelectric properties of Zn₂SnO₄-based composite nanomaterials

The zinc (Zn)-type compound zinc stannate (Zn₂SnO₄) is critical in the field of thin-film solar cells and photocatalysis. In this study, a new composite nanomaterial zinc stannate/tin (IV) oxide (SnO₂) was synthesised through a high-temperature synthesis spray process. The electrochemical properties of the samples were tested. Besides, different ratios of zinc stannate/tin (IV) oxide nano-heterostructures were synthesised by using the ion exchange method, with zinc stannate nanocrystals as substrates. Also, their photocatalytic activities in a three-electrode system of simulated solar light sources were discussed. The photoelectric property of zinc stannate/tin (IV) oxide obtained from the solvothermal method was tested. The photocurrent of the obtained zinc stannate/tin (IV) oxide thin-film reached 2.6 μA, while the photocurrent of the zinc stannate thin film was only 0.13 μA. In the meantime, the fluorescence spectrum test proved that the recombination of zinc stannate and tin (IV) oxide reduced the recombination of photo-generated carriers. The photocatalytic test of zinc stannate/tin (IV) oxide obtained from the ion exchange method showed that given a 0.5 V reversible hydrogen electrode, the photocurrent of zinc stannate/tin (IV) oxide reached 0.62 mA/cm². This indicator was 10 times the value of pure zinc stannate photocurrent under the same condition, which showed an increase in the photocatalytic capacity of zinc stannate. It proved that zinc stannate/tin (IV) oxide composite nanomaterials have better photoelectric performances and application prospects in the fields of solar cells and photocatalysis.