Investigation On The Synthesis Of Ternary Cu-based Chalcogenide Nanocrystals And Their Application In Thin Film Solar Cells

The solar cell is one of the main methods of solving the current energy crisis and environmental problems.Among them, the thin film solar cells which was named the second generation solar cell has come to the foreground because their theory conversion efficiency can reach 31%.Thin film solar cells mainly contains absorption layer, buffer layer and window layer. ?-?-?2 semiconductor nanocrystals is a promising materials for light absorption layer of thin film solar cells. The semiconductor nanocrystals, which consisted of the group of ? (Cu), ?(In), ?2 (S, Se), are direct bandgap semiconductors, the band gap values between 1.0 eV to 1.7 eV, match with the solar spectrum.The light absorption layer material of thin film solar cells was fabricated by two kinds of method: RF sputtering and evaporation were vacuum method; nanocrystal ink and Chemical spray pyrolysis were vacuum method. Compared with vacuum method need expensive equipment and complex process, the non-vacuum method has advantages(simple and low cost). The non-vacuum method has a large number of values in the field of thin film solar cells. In the thesis, the CuInS2 nanocrystal and Cu3BiS3 nanosheet were prepared. The sintering process in preparation of CuInSe2 thin films and their application in the thin film solar cell were investigater. And Cu3BiS3 nanosheets' application in photoelectric response. The main contents are as follows:1. CuInS2 nanocrystals were synthesized by organometallic thermal decomposition method with oleylamine and dodecanethiol used as capping agents. CuInS2 nanoink was formed by dispersing CuInS2 into ODCB solvent, and CuInS2 thin film was fabricated by spin coating nanoink onto glass substrate. The CuInSe2 thin films were formed after selenization process under different temperature. SEM, XRD, and Raman were used to characterize composition and structure properties of obtained CuInSe2 thin films.2. The CuInSe2 thin film solar cells were fabricated after selenization process, followed by CdS layer by CBD method, ZnO and ITO layers by RF sputtering. The addition of In2S3 was performed to reduce the effect of CuxSe. The photovoltaic performace of CuInSe2 thin film solar cells were evaluated by J-V curves and IPCE spectra. The PCE of 2.16% was achieved after the optimized parameter under AM 1.5 100 mW/cm2.3. Cu3BiS3 nanosheets were synthesized by organometallic thermal decomposition method. The formation mechanism of Cu3BiS3 nanosheets was investigated. The measurements on I-V curves implied that the obtained Cu3BiS3 nanosheets exhibited good photoelectrical response.