The lattice reconstruction of Cs-introduced FAPbI1.80Br1.20 enables improved stability for perovskite solar cells. Issue 7 (20th January 2021)

• Record Type: Journal Article
• Authors: Chen, Shuang; Pan, Lu; Ye, Tao; Lei, Nuo; Yang, Yijun; Wang, Xi
• Is Part Of: RSC advances. Volume 11:Issue 7(2021)
• Page Start: 3997
• Page End: 4005
• Publication Date: 2021-01-20
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra09294k
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The Cs0.15 FA0.85 PbI1.80 Br1.20 perovskite shows excellent structural stability, while 15% Cs + can reduce specific traps such as Pb 0 and I 0 . Abstract : Inorganic–organic hybrid perovskite solar cells (PSCs) have stirred up a new research spree in the field of photovoltaics due to its high photoelectric conversion efficiency and simple preparation process. In recent years, the research of inorganic–organic hybrid PSCs has been widely reported, among which FA + /Cs + PSCs are especially outstanding. However, there are few reports explaining the lattice structural change mechanism of Cs x FA1− x PbI1.80 Br1.20 PSCs from the view of chemical bonds. In this work, a facile method of 15% Cs + cations partially substituting FA + cations has been presented to enhance the structural stability and photovoltaic performances of FAPbI1.80 Br1.20 PSCs. The partial incorporation of Cs + in FAPbI1.80 Br1.20 resulted in a more beneficial tolerance factor and inhibited the deep defect state of elemental Pb. More importantly, it inhibited the phase transition from the cubic black α-phase to the hexagonal yellow δ-phase of FAPbI1.80 Br1.20 . Moreover, the power conversion efficiency (PCE) of Cs0.15 FA0.85 PbI1.80 Br1.20 PSCs achieved a substantial improvement. The stability also achieved a remarkable promotion, which was demonstrated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Nuclear Magnetic Resonance (NMR). These analyses indicate that 15% Cs + can induce the lattice shrinkage, reduce the specific traps and inhibit the phase transition, thus improving the structural stabilities of Cs0.15 FA0.85 PbI1.80 Br1.20 PSCs under atmosphere and calefaction. These results provide an effective way for fabricating stable and efficient inorganic–organic perovskite solar cells with promising properties.