Preparation Of Zinc Oxide Nanomaterials And Its Application In Quantum Dot Sensing Solar Cells

Energy crisis is the greatest challenge in21st century. Developing low-cost, highefficiency solar cells is one of the effective way to solve this problem. The development ofnano-materials and semiconductor nanocrystals as light harvesters bring new opportunitiesfor the next generation solar cells. Highly oriented nanowires, nanorods, nanotubes andother shapes of nano-materials can improve electron transfer, reduce electron and holerecombination in dye-sensitized solar cells. Semiconductor nanocrystals （quantum dots）open up new ways to utilize hot electrons or generate multiple charge carriers with a singlephoton. Their size quantization property allows tune the visible response and improvecharge transfer across different sized particles. Which make the break through of thetheoretical limit efficiency of traditional solar cells. ZnO is a wide bandgap semiconductor,electrons have faster migration rate in ZnO, ZnO is easier to change in morphology.Therefore, we propose the rsearch of quantum dot-sensitized solar cells （QDSSC） based onZnO nano-materials. In this paper, various ZnO nano materials have been obtained byelectrochemical deposition and hydrothermal method, part of them can be used in QDSSC.An aqueous solutio of Zn（NO₃）₂·6H₂O （used as the electrolyte） was mixed with someKCl （used as the supporting electrolyte） for the electrodeposition. The effect of temprature,concentration of Zn（NO₃）₂·6H₂O and KCl for the morphology of obtained materials havebeen studied. Zn₅（OH）₈Cl₂·H₂O plate films have been obtained as the precursor of ZnOporous plate films（after heat treatment）. The Zn₅（OH）₈Cl₂·H₂O plates changed to porousZnO induced by electron beam irradiation has been observed. A new kind of hierarchicalStructured ZnO Nanorods and ZnO dendritic structures have been synthesized byelectrodeposition.ZnO porous plate films have been used in QDSSC. The effect of quantum dots,electrolyte and CBD ycles for the performance QDSSC has been studied. The highestconversion efficiency of0.37%and0.33%has been obtained by using Pt and Au counterelectrode. A kind of hierarchical ZnO nanowire-nanosheet architecture has beensynthesized by combining electrodeposition with hydrothermal method. The efficiencyQDSSC can be increased from0.183%to0.3%after the ZnO porous plate films undertreatment by hydrothermal method.The effect of concentration of electrolyte for the morphology of obtained materialshave been studied at pH=10in hydrothermal process. ZnO nanowires, nanorods andnanotubes have been successfully synthesized by hydrothermal method. The QDSSC fabricated by three kind of ZnO nano materials exhibited conversion efficiency rangingfrom0.177%to0.346%when illuminated with100mW/cm2simulated AM1.5Girradiation.