Amino acids assisted growth of methylammonium lead iodide cuboidal crystals for solar cell applications

The cuboidal crystals of methylammonium lead iodide (MAPbI3) with controlled shapes and sizes are successfully synthesized by monitoring their growth in the precursor solution using different α-amino acids. The directional growth of MAPbI3 crystals is carried out by promoting crystallization at molecular level in the presence of an optimum concentration of α-amino acids. Alanine (ALA), having relatively larger value of dipole moment, induces directional growth to the MAPbI3 crystals at low concentration. The optical and electrical properties of the thin films formed by the grown MAPbI3 crystals are also enhanced. The dipole moment of the amino acids plays an important role in directional growth of MAPbI3 crystals. The least area of I-V hysteresis curve in the thin film prepared with 1.5 wt% of isoleucine (ISO) indicates minimum loss of energy which makes it suitable for application in perovskite solar cells (PSCs).