Strain engineering in perovskite solar cells and its impacts on carrier dynamics

• DOI: 10.1038/s41467-019-08507-4
• Publication Date: 2019-02-18T11:03:22Z
• Authors: Cheng Zhu; Xiuxiu Niu; Yuhao Fu; Nengxu Li; Chen Hu; Yihua Chen; Xin He; Guangren Na; Pengfei Liu; Huachao Zai; Yang Ge; Yue Lu; Xiaoxing Ke; Yang Bai; Shihe Yang; Pengwan Chen; Yujing Li; Manling Sui; Lijun Zhang; Huanping Zhou; Qi Chen
• Keywords: Composite material; Silicon; Thin-Film Solar Cells; Bending; Science; Perovskite Solar Cell Technology; Chemical physics; Materials Science; 02 engineering and technology; 7. Clean energy; Article; Engineering; FOS: Electrical engineering, electronic engineering, information engineering; Materials Chemistry; Strain engineering; Crystallite; Electrical and Electronic Engineering; Optoelectronics; Perovskite (structure); Biology; Two-Dimensional Materials; Crystallography; Physics; Q; Solar cell; Strain (injury); Acoustics; Condensed matter physics; Lattice (music); Computer science; Materials science; Thin-Film Solar Cell Technology; Algorithm; Chemistry; Residual; Physical Sciences; Metallurgy; Perovskite Solar Cells; Anatomy; 0210 nano-technology

AbstractThe mixed halide perovskites have emerged as outstanding light absorbers for efficient solar cells. Unfortunately, it reveals inhomogeneity in these polycrystalline films due to composition separation, which leads to local lattice mismatches and emergent residual strains consequently. Thus far, the understanding of these residual strains and their effects on photovoltaic device performance is absent. Herein we study the evolution of residual strain over the films by depth-dependent grazing incident X-ray diffraction measurements. We identify the gradient distribution of in-plane strain component perpendicular to the substrate. Moreover, we reveal its impacts on the carrier dynamics over corresponding solar cells, which is stemmed from the strain induced energy bands bending of the perovskite absorber as indicated by first-principles calculations. Eventually, we modulate the status of residual strains in a controllable manner, which leads to enhanced PCEs up to 20.7% (certified) in devices via rational strain engineering.