One-dimensional facile growth of MAPbI₃ perovskite micro-rods

One-dimensional microrods (4-5 mm) of PbI₂ and CH₃NH₃PbI₃ (MAPbI₃) with unique structural and morphological properties have been grown at room temperature. X-ray diffraction (XRD) patterns of both types of micro-rods exhibit a hexagonal system (P3̄m1(164) space group) with 2H polytype structures. In the case of PbI₂, the atomic composition of the microcrystals indicates the formation of pure phases of PbI₂, however, energy-dispersive X-ray spectroscopy (EDX) of MAPbI₃ indicates the existence of intermediate phases due to the addition of MAI. FTIR results reveal the existence of a strong interaction between C-H and N-H groups in the crystals which has been cross validated by Raman spectroscopic analysis. The morphological studies performed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirm the crack free morphology of PbI₂ and MAPbI₃ micro-rods with a porous structure. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) studies show that the addition of MAI in the PbI₂ reduced the weight loss and the decomposition temperature has been increased by 1.5 °C as well. The growth of these unique one-dimensional micro-rods signifies a novel concept in perovskite synthesis for solar cells and optoelectronic applications.