Controllable synthesis of novel Cu2O micro/nano-crystals and their photoluminescence, photocatalytic and field emission properties

Abstract

Herein, two kinds of micro/nano-sized single-crystalline cuprous oxide (Cu₂O) crystals with novel porous cubic or hierarchical rod-like morphologies were successfully synthesized via a facile ethanol-assisted double-solvothermal method. It was found that the addition of ethanol in precursor solution is critical for the formation of hierarchical rod-like structures (to be called nano-bamboo shoots in this paper). The detailed growth mechanism analyses indicated that the morphology transition from micro-porous cubes to quasi-one dimensional (1D) nano-bamboo shoots was due to the occurrence of branching growth as the reaction time increased. Besides, the photoluminescence (PL) measurement was introduced to evaluate the quality of crystalline and the results revealed that V_Cu and V_O⁺ existed in both typical samples. The photocatalytic abilities of the as-prepared Cu₂O crystals were investigated for the photodegradation of methyl orange (MO), and the results demonstrated that the nano-bamboo shoots had excellent photocatalytic performance due to its unique hierarchical structure with most exposed {110} facets. Moreover, the field emission properties of as-prepared two samples were measured for the first time. The results indicated that the micro-porous cubes samples which contained branching structures with sharp tips possessed better field emission performance with a lower turn-on field of 3.1 V μm⁻¹, lower threshold field of 11 V μm⁻¹ and larger field enhancement factor of 2365, implying its potential application for field emission display devices.