Synthesis And Properties Of CdS Nano Thin Films

Cadmium telluride(Cd Te)solar cell which has caused worldwide concern because there are many advantages,such as higher theoretical conversion efficiency,inexpensive,easy operation and industrialization ect,which has been one of the most development solar cells.During many heterojunction salor cells,such as Cd Te solar cell,Pb S solar cell and Cu In Se2 solar cell.ect,CdS plays a role of window layer,Cd Te,Pb S and Cu In Se2 are used as absorbed layer.however,the photoelectric conversion efficiency of solar cell odule depend on the crystal quality of CdS layer and the property of heterojunction,so it is vital significance to synthesis and properties of CdS nano thin film of high quality.in this paper,we employ chemical bath deposition method to synthesis CdS nano thin film.firstly,we study the whole progress about preparation of CdS nano thin film and analyze characterization of thin film.secondly,we reaserch optical absorption and photoelectric property of CdS nano thin film.finally,we dope Zn element into CdS nano thin film and study the influence on CdS thin film.the main work is as follows:(1)we adopt chemical bath deposition method to synthesis CdS nano thin film on the base of FTO.in the solution what is used to synthesis CdS nano thin film,the cadmium source is supplied by cadmium salt,the sulphur source is provided by thiourea.the ammonium salt is employed as buffering agent and provide complexing agent.we study the impact of time and temperature of deposition on the CdS thin film and we find that CdS crystalline size magnifies,the thickness and density of the film increases with time of deposition.meanwhile,photoelectric property increases then decreases with time of deposition,optical absorption also presents increases tendency.when the time of deposition is 105 min,photoelectric property of CdS nano-film is best,short-circuit current density is 1.15 m A/cm2,open-circuit voltage is 0.76,photoelectric conversion efficiency ? is 0.323%,thickness is 170 nm.when we change the temperature of CdS nano-film deposition in the condition of other conditions unchanged,we find that CdS crystalline size,the thickness and density of the film increases with temperature of CdS nano-film deposition,meanwhile,optical absorption presents increases tendency,photoelectric property increases then decreases with temperature of deposition,when temperature is 80?,photoelectric property of CdS nano-film is the best,short-circuit current density is 1.2m A/cm2,open-circuit voltage is 0.75,photoelectric conversion efficiency ? is 0.335 %,thickness is 180 nm.the phenomenon appeared which becauses specific surface area increase,which leads to produce more photogenerated electrons,and density of the film increases,which protects FTO from contacting with electrolyte directly to decrease recombination of photogenerated carrier,when CdS crystalline size increases with time and temperature of deposition.at the same time,we study the influence of annealing temperature on CdS nano-film,when annealing temperature is 400?,crystallinity is the best.(2)we dope Zn element into CdS nano thin film to improve photoelectric property and stability of CdS nano-film.we adopt chemical bath deposition method to synthesis CdS nano thin film,and we find that Zn doped has a important influence on CdS nano-film,there are not changes about the structure and morphology of thin film.however,compared with Zn undoped,photoelectric property and optical absorption of Zn doped is better,short-circuit current density is 1.43 m A/cm2,opencircuit voltage is 0.9,photoelectric conversion efficiency ? is 0.49 %,thickness is 180 nm.by measure of I-t,short-circuit current density changes slower of Zn doped,this illustrates more stability of Zn doped than unpoded.