| Summary: | 碩士 === 國立臺灣科技大學 === 材料科學與工程系 === 100 === Abstract
Due to energy crisis, the research of solar cells is recently much more attractive. The main compound solar cell is the Cu(In,Ga)Se2 system, but the high cost has limited its further applications. Lowing the cost with the finding of new materials is necessary, therefore Cu2ZnSnS4(CZTS) and Cu2ZnSnSe4 (CZTSe) solar cells with energy band gaps of 1.5 eV and 0.9-1.07eV, respectively, are developed.
In this study, CZTSe solar cells were prepared by using paste-printing on alumina substrates. Four kinds of cold-pressed absorber layers with the composition A(CZTSe-ceramic), B(CZTSe-ceramic+20mol%Te), C(CZTSe-cermet), and D(CZTSe-metal) were prepared by paste printing. Sintering and selenization were conducted by a two-step heating procedure. The first step was at 300℃for 1 h and it held at 600 ℃,650℃ or 700℃ at the second step. The CZTSe solar cell was constituted with the stacking of Ag/ITO/ZnO/CdS/screen-printed CZTSe/CIGS/Mo/Al2O3. The quality of the absorption layer was analyzed by XRD and FE-SEM microscope equipped with energy dispersive X-ray spectrometer. The performance of the solar cells was evaluated under the standard AM1.5 illumination.
The experimental results showed surface morphologies of paste-printed CZTSe films with composition-A and composition-B became denser but were unable to observe grains after the precursor films were selenized at higher temperatures with a two-step heating procedure.
For paste-printed CZTSe films with composition-C and composition-D, it became denser and smooth and the larger grains were easily observed after the precursor films were selenized at higher temperatures with a two-step heating procedure. The CZTSe films were a single phase at different selenization temperatures. Electrical properties of the selenized films were measured. The solar cell devices made from composition-C and composition-D were evaluated after a two-step selenization at 650℃ with power conversion efficiencies of 1.465% , 1.138%, respectively.
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