Study Of Sb₂Te₃Back Contact On CdTe Thin Film Solar Cell

Among the new energy which are developed and utilized, the application of thesolar cells has become one of the most influential and fastest-growing field inscientific research, and is a useful way to solve the conflictions among economy,environment and energy in the world today. On the whole, preparation of low cost andefficient solar cells will become the direction of the solar cell development in thefuture. In the field of thin film solar cells, CdTe thin solar cells have drawnmuch attention, because it is highly efficient, low cost, simply prepared and easilyindustrialized and so on. CdTe thin film solar cells have attracted much attention inthe research of thin film solar cells for the last three decades. However, several keytechnologies must be solved in order to prepare high efficiency CdTe thin solar cells.The back contact layer technology is one of them. In this paper, we used Sb2Te3as aback contact layer in the battery. Firstly, we have studied the preparation,characterization and ohmic contact property of Sb2Te3thin film. Finally, Sb2Te3backcontact layer was applied to CdTe thin film solar cells, and we studied its influence onthe performance of battery. The main work is as follows:(1) It is reported here that the cauliflower-like nanorods array films of Sb2Te3on Ni substrate has been developed by electrochemical deposition method. Throughthe test of cyclic voltammetry technique in the solution, we found the best depositionvoltage of cauliflower-like nanorods array of Sb2Te3. By changing the concentrationof nitric acid, wheat-like nanorods array films of Sb2Te3were prepared on the Nisubstrate. We studied the ohmic contact property of the cauliflower-like nanorodsarray films of Sb2Te3, its I-V characteristic curve is a straight line through the origin, and present ohmic contact property.(2) CdTe thin films were prepared on the top of Sb2Te3thin films byelectrochemical deposition method, and the thickness of CdTe thin films is about1.5μm. Then CdS thin films were prepared on the top of CdTe thin films by chemicalbath deposition method, and the thickness of CdS thin films is about200nm. Finally,SnO2thin films were prepared on the top of CdS thin films by thermal evaporationmethod. We used Ni substrate and SnO2thin films respectively as the positive andnegative electrodes of the CdTe thin film solar cell, and got the battery withphotovoltaic (pv) effect. The short-circuit is3.58mA/cm2, the open circuit voltage is0.39V, the fill factor is22.42%, and the photoelectric conversion efficiency is0.313%,the measurement area is0.5cm2. The short-circuit of the CdTe thin film solar cell thatdon’t have Sb2Te3back contac layer, is1.76mA/cm2, the open circuit voltage of thatis0.37V, the fill factor of that is22.88%, and the photoelectric conversion efficiencyof that is0.149%, the measurement area is0.5cm2. It is indicated that Sb2Te3is a kindof good back contac layer.