Surface Modification Of Cadmium System Quantum Dots In The Solar Cells

With the increasing demands for the energy source,clean,efficient and renewable energy has become the focus of scientific research and the lifeblood of the national economy.Due to many advantages of quantum dot solar cell such as low cost and simple manufacturing process,it has become the most promising solution for developing the third generation solar cells.In this work,thorough research was conducted on the cadmium quantum dots(Cd Se and Cd Te).Cd X(X=Se,Te)colloid quantum dots was surface modified using mixed inorganic coordination and surface inorganic nanoscale shell design.Then the optical,electrical and optoelectronics properties and thermal stability of as-prepared Cd X colloid quantum dots was studied.Based on the classical Cd Te/Zn O(II)heterojunction quantum dot solar cell structure,the effects of the above two methods of modification on the improvement of solar cells performance were verified.The results are as follows:1.With the control of the synthetic parameters and process,synthesis formulation of high quality Cd Se and Cd Te quantum dots was acquired.Cd Se and Cd Te quantum dots was synthesized by heat injection method.2.Surface ligand replacement of the cadmium system quantum dots was done to achieve its application in solar cell devices.The optimal experiment parameter was determined: Adopting the structure of ITO/Zn O(60nm)/Cd Te(400nm)/Au(100nm)and annealing at 350 °C for 20 s.The photoelectric conversion efficiency(PCE)of as-acquired device was 2.63%,Jsc=15.77 m A/cm2,Voc=0.46 V,FF=35.92%,IPCE>50%.The efficiency of as-acquired device remains obove 87% after being exposed in the air for 12 hours.3.Surface shell design of cadmium system quantum dots was done to achieve its application in solar cell devices.The optimal experiment parameter was determined: Single Cd Se coated Cd Te/Cd Se core-shell quantum dots and the structure of ITO/Zn O(60nm)/Cd Te(400nm)/Au(100nm)and annealing at 350 °C for 20 s.The photoelectric conversion efficiency(PCE)of as-acquired device was 2.45%,and Jsc=19.60 m A/cm2,Voc=0.42 V,FF=22.40%,IPCE>80%.The efficiency of as-acquired device remains obove 95% after being exposed in the air for 12 hours.