Tunable Formation of ZnSe to ZnO due to a Controlled Phase Transition Driven by Hydrazine and Sodium Hydroxide

Fen Qiao 1, Email

Qichao Liang 1

Xuejun Cui 2

Qian Xu 3

Yi Xie 4

Huaqiang Chu 5, Email

1 School of Energy and Power Engineering, Jiangsu University, Zhenjiang, 212031, China
2 College of Chemistry, Jilin University, Changchun 130012, China
3 Institute for Energy Research of Jiangsu University, Jiangsu University, Zhenjiang 212031, China
4 State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China
5 School of Energy and Environment, Anhui University of Technology, Ma'anshan 243002, China

Abstract

Controllable ZnSe and ZnO structures with different morphologies were synthesized by a simple hydrothermal method. The effects of hydrazine hydrate and sodium hydroxide on the final product and morphology were studied. The results showed that controlled phase transition from ZnSe to ZnO was achieved by adjusting the volume of hydrazine hydrate. The structure variety of as-synthesized product depended on the hydrazine hydrate volume and sodium hydroxide concentration, which was further confirmed by SEM and XRD. It showed that hydrazine hydrate acted a pivotal part in the restoring process of selenium. Pure ZnSe microspheres were obtained when the volume of N2H 4·H2 O increased to 10 mL. While the final product completely changed into ZnO rods when the N2H4 ·H2O was absent during the synthesize process. Additionally, when the concentration of NaOH was higher than 0.5 M, ZnO tended to self-assemble into flower-like ZnO structures. The corresponding reaction mechanism was discussed. The current-voltage characteristics indicated that self-assembled flower-like ZnO structures displayed excellent electrical properties, which was attributed to the special structural feature with large specific surface area and defect states formed by adjusting the sodium hydroxide concentration. This facile approach for phase transition from ZnSe to ZnO may provide an alternative way for preparation of functional heterostructure, which demonstrates their potential application in optoelectronic devices.

Tunable Formation of ZnSe to ZnO due to a Controlled Phase Transition Driven by Hydrazine and Sodium Hydroxide