Pyrrolidinium induced templated growth of 1D-3D halide perovskite heterostructure for solar cell applications

Stability issues of perovskites have narrowed down their possibility of taking over photovoltaic market. In this scenario, we have introduced 1D-pyrrolidinium lead iodide (PyPbI₃) into 3D-Methylammonium lead iodide (MAPbI₃) perovskite under open atmosphere. Our studies showed the incorporation of pyrrolidinium ion into 3D lattice unit and also the favourable assembly of 1D perovskite throughout 3D perovskite structure. We confirm the formation of 1D-3D hybrid halide structure by X-ray diffraction (XRD) patterns and High Resolution-Transmission Electron Microscopy (HR-TEM). The optical and surface morphology studies affirmed the changes in band gap and considerable improvement in grain size by PyI addition. X-ray Photoelectron reveals the bonding between pyrrolidinium ion and lead iodide in 1D-3D hybrid halide structure, which results in the reduced oxygen adsorption and increased moisture stability of the films. The reduced wettability is confirmed by contact angle meter study. Overall, the films were stable in open atmosphere for approximately a month. Importantly, incorporation of 1D perovskite helps to release the tensile strain within the thin film. We were able to successfully fabricate the solar cells of them and the highest efficiency of 7.5% was obtained for 10 mol % PyI perovskite.