Investigation Of Thin Films Using In CIS Solar Cell Prepared By Spray Pyrolysis

In the last decades, solar cells (converting sunlight into electricity) have attracted much attention as a proper candidate for the renewable and clean energy source in the future. Most of industrial produced solar cells are based on vacuum process, which increases the cost of solar cells. These solar cells such as crystal silicon solar cell, it consumes a lot of energy in the production processes. To solve these problems, we use spray pyrolysis under atmospheric environment to prepare the layers of CuInS2 thin film solar cells. Specific researching results are as follows:CuInS2 thin films were prepared by ultrasonic spray pyrolysis on glass substrates, the structures and optical properties of CuInS2 were characterized. The influences of preparation parameters such as substrate temperature, Cu/In atomic ratios and annealing conditions have been investigated. Optical microscope and XRD test reveals the surface morphology of samples and crystal properties, respectively. The band gap of CIS samples is around 1.45eV by calculation using the transmission spectrum. Semiconductor type has been investigated by hot and cold probe test and the samples are p type semiconductor. As ratio of Cu increased, conductive type tends to this levy, carrier concentration increased and resistance reduced. Therefore, the samples prepared by spray pyrolysis are suitable to be absorbing layers for solar cells.The Mo and glass substrates influence of CuInS2 thin films were compared. It showed that under the same preparation conditions, the performance trend of the CuInS2 thin film on Mo and glass substrates were similar, but films on Mo substrates are superior to film on the glass substrate in crystallinity, uniformity, film flatness and the surface morphologies, hi addition, the influences in lattice parameters of different substrates also have been researched.As window layer, AZO conductive film was also prepared by ultrasonic spray pyrolysis. The effect of processing parameters, such as the isopropanol-water ratio and substrate temperature, spray times, spray rate and annealing conditions were investigated on the structure and properties of AZO thin films. It showed that the best performance conditions of samples were spray speed in 4 ml/min, spray time in 30 min and isopropanol-water ratios in 4:1. When the substrate temperatures were 350 ℃ and 500℃, the samples have better conductivity. And vacuum annealing can significantly improve the electrical and optical properties of samples.The buffer layer In2S3 thin films were also prepared by ultrasonic spray pyrolysis at 300-400℃.The band gaps of samples were 3.01 eV to 3.22 eV and suitable as buffer layers of CuInS2 solar cell.