Well-aligned ZnO nanoneedle arrays grown on polycarbonate substrates via electric field-assisted chemical method

• A relatively fast and easy technique is used for the synthesis of ZnO nanoneedles.
• We report the growth of aligned ZnO nanoneedles on flexible PC substrates.
• We report the shape transitions from rod to needle shape based on current density.
• ZnO nanoneedles show superior antireflective properties.

Well-aligned ZnO nanoneedle arrays were prepared for the first time on polycarbonate (PC) substrates via an electric field-assisted chemical method. The surface morphologies of ZnO nanoneedles at different current densities were studied using field emission scanning electron microscopy. The X-ray diffraction pattern of the ZnO nanoneedle arrays showed strong c-axis oriented crystal structure with preferred (0 0 2) orientation. Room-temperature photoluminescence measurement of the ZnO nanoneedles revealed an ultraviolet peak at 380 nm, which is comparable with those found in high-quality ZnO films. UV–visible spectroscopy was also conducted to study further the optical properties of ZnO nanoneedles. The growth of ZnO nanoneedles on PC substrate exhibited the greatest absorption enhancement and the best antireflective property, which indicated that this product has great potential for the applications in energy-harvesting devices and flexible solar cell applications.