Ultra-fast microwave-assisted hydrothermal synthesis of long vertically aligned ZnO nanowires for dye-sensitized solar cell application

Abstract

Long vertically aligned ZnO nanowire arrays were synthesized using an ultra-fast microwave-assisted hydrothermal process. Using this method, we were able to grow ZnO nanowire arrays at an average growth rate as high as 200 nm min(-1) for maximum microwave power level. This method does not suffer from the growth stoppage problem at long growth times that, according to our investigations, a normal microwave-assisted hydrothermal method suffers from. Longitudinal growth of the nanowire arrays was investigated as a function of microwave power level and growth time using cross-sectional FESEM images of the grown arrays. Effect of seed layer on the alignment of nanowires was also studied. X-ray diffraction analysis confirmed c-axis orientation and single-phase wurtzite structure of the nanowires. J-V curves of the fabricated ZnO nanowire-based mercurochrome-sensitized solar cells indicated that the short-circuit current density is increased with increasing the length of the nanowire array. According to the UV-vis spectra of the dyes detached from the cells, these increments were mainly attributed to the enlarged internal surface area and therefore dye loading enhancement in the lengthened nanowire arrays.

Low-Temperature Preparation of a Carbon Nanotube–ZnO Hybrid on Glass Substrate for Field Emission Applications

“…34 This is a lowtemperature method for synthesis of ZnO nanowires. Figure 3 is a SEM image of ZnO nanowire on a glass substrate (top view) with a seed layer formed by spin-coating.…”

“…Ammonium hydroxide and polyethylenimine (PEI) was employed to improve this method. [32][33][34] Figure 1 is a schematic of ZnO nanowires synthesized on vertically aligned CNTs. This method also requires two stages.…”

“…34 A layer of zinc oxide was then coated on the vertically aligned CNTs by spin-coating and hydrothermal processing was carried out for the growth of the ZnO nanowire. The ZnO nanowires on the CNTs were of high density and uniform.…”

Development of Macro-Porous Silicon Based Dye-Sensitized Solar Cells with Improved Light Trapping

“…This feature is derogated by reducing film thickness in thin-film solar cells such as dye sensitized solar cell (DSSC); therefore, many approaches are made to improve it. For example, porous active layer with high surface area [1][2][3], hierarchically nanostructures as photoanode [4][5][6], scattering layers on the top of active film [7][8][9], plasmonic photoanodes [10][11][12] and photonic crystal photoanodes [13][14][15] have been applied for changing the optical design of the DSSC to optimize its light absorbance. Since the mentioned approaches have some limitations like high reflectance loss and low dye adsorption, researchers are still extensively eager to explore the new light trapping structures as photoanode.…”

Highly selective and responsive ultra-violet detection using an improved phototransistor

“…1 ZnO has been vastly used in many applications. Various growth methods of ZnO nanostructures has been developed and among them, aqueous methods like hydrothermal [2][3][4] and microwave assisted 5,6 growth of ZnO nanorods (NRs) are commonly used to synthesize fairly high quality ZnO nanorods. 7 ZnO nanostructures are very interesting for sensing applications mainly because of their high surface to volume ratio.…”