Fabrication And Application Research Of Cu₂ZnSnS₄ Single Crystalline Nanosheet Arrays

In this thesis, we firstly fabricate CuS single crystalline nanosheet arrays(NSs) on the FTO substrate, and obtain Cu2ZnSnS4(CZTS) single crystalline NSs using the CuS NSs as sacrifice template. Then we use the CZTS NSs as photocathode of photoelectrochemical(PEC) water splitting system. And we try to use the CuS and CZTS NSs as the counter electrodes of quantum dot solar cells. The main results are as follows:Successfully fabricate the CuS NSs using the method of gas phase sulfide, then synthesis the CZTS NSs on FTO substrate through ion exchanging. We make basic structure and physical characterization for these two materials and discuss their formation mechanism respectively.The bare single crystalline CZTS NSs are applied as photocathodes for PEC solar hydrogen production in an alkaline solution, and get the highest current ever reported for CZTS based electrode without co-catalyst and protective layer. We compare the performance of the 3D CZTS NSs and the traditional CZTS film, and find that the CZTS NSs have better photo absorb capability, longer carrier lifetime, and larger surface area. So the photocurrent density of CZTS NSs photocathode is about 2.2 times larger than that of the CZTS film.CuS and CZTS NSs are used as the counter electrodes of quantum dot solar cells respectively, and compared with Pt film electrode. The results show that CuS and CZTS NSs perform much better than the Pt film electrode. The CZTS single crystal NSs have remarkable catalytic properties and transmission performance, and the CuS single crystal NSs have good cycle performance.