Lei Meng,Bin Yao,Yongfeng Li,Zhanhui Ding,Zhenyu Xiao,Kaisi Liu,Gang Wang
The back contact adhesion is the important factor of the microstructural performance which can determine the optoelectronic properties of the kesterite-based solar cells. Here, we present a rational and effective strategy to significantly enhance the back contact adhesion of Cu 2 (Zn,Cd)Sn(S,Se) 4 (CZCTSSe) absorber layers by insetting the appropriate thickness carbon-doping CZCTS thin films . We chose the oleylamine as the carbon-doping reagent which can generate a small amount of carbon in the annealing process . The suitable thickness carbon-doping CZCTS films can significantly change the crystal growth mechanism of CZCTSSe absorber layers, and eliminate the holes in the back contact. The efficiency of CZCTSSe solar cells fabricated by insetting the appropriate thickness carbon-doping CZCTS films is above 7%, and shows the excellent repeatability and long-term air stability compared with the control devices.
2D nonlayered materials have attracted more and more attention due to their novel properties and special surface structures. However, due to isotropic chemical bonds within the crystal, the synthesis of ultrathin 2D nonlayered materials is an urgent challenge. Herein, α -Fe 2 O 3 2D nanosheets as thin as ≈8.2 nm on different substrates using self-designed ultralow concentration precursors combined with Gibbs free energy and Se catalysts design are successfully synthesized. The thickness-dependent growth mechanism is systematically studied, demonstrating the thermodynamic and kinetic controlling factors. The as-grown α -Fe 2 O 3 nanosheets are demonstrated with single-crystal structures without any other elements doping. The α -Fe 2 O 3 nanosheets photodetectors show the reasonable response performance with the positive photoconductive mechanism. This improved chemical vapor deposition method provides a promising idea for the synthesis of ultrathin 2D nonlayered materials.