Manipulated the band gap of 1D ZnO nano-rods array with controlled solution concentration and its application for DSSCs

One-dimensional (1D) ZnO nano-rods array was grown by the hydrothermal method. ITO substrates were immersed in equal-molar of zinc nitrate (Zn(NO)3·6H2O) and methenamine (C6H12N4) aqueous solution at 90 °C for 24 h to grow ZnO nano-rods. The reaction solutions with different molar concentrations were used to growth different thickness and diameter of ZnO nano-rods. The shape of ZnO nano-rods is hexagonal and the grain size can be changed from 30 nm to 500 nm with the prefer orientation of (002). Finally, ZnO nano-rods films were used as electrode materials to fabricate dye sensitized solar cells (DSSCs). A fill factor of 33.43%, short-circuit current of 11.877 mA/cm2, open-circuit voltage of 0.486 V and an overall light to electricity conversion efficiency of 1.932% were obtained.

► The reaction solutions with different molar concentrations were used to growth different thickness and diameter of ZnO nano-rods.
► The shape of ZnO nano-rods is hexagonal and the grain size can be changed from 30 nm to 500 nm with the prefer orientation of (002).
► Controlling the size, shape, and crystalline structure of the ZnO nano-rods for the improvement of the opto-electrical properties of DSSCs.