Research at the Department of Physics envisions future studies on the anisotropic properties across various planes of their reported MAPbBr3 crystals and identifying the better plane for efficient electrical contact in device applications. Assistant Professor Dr Sabyasachi Mukhopadhyay and his research scholar Kunchanapalli Ramya recently published the paper Room-Temperature Cost-effective In-situ grown MAPbBr3 Crystals and their Characterization towards Optoelectronic Devices in the journal Material Science and Engineering: B. The paper has an impact factor of 3.407. They have done this work in collaboration with Sr Satyajit, IIT- Bhilai. This is the first article published under the Indo- Israel bilateral project A Halide Perovskite-Based Photoanode for Oxygen Evolution Reaction Using a Molecular Diode in a Hybrid Nanometer Scale.
The paper reports the in-situ, room-temperature synthesis of methylammonium lead bromide CH3NH3PbBr3 crystals using N-methyl formamide as a source of methylammonium (MA+) ions during the crystallization process to explore the structural, dielectric, and electronic properties of CH3NH3PbBr3 crystals for optoelectronic applications. Optical absorption and radio-luminescence measurements affirm the direct bandgap nature of the crystals. Impedance spectroscopy measurements with various applied AC voltages within the 20 Hz – 10 MHz frequency range depict the influence of ionic motions on electrical transport across crystal planes. Researchers have extracted electrical transport parameters in CH3NH3PbBr3 crystals from the Nyquist plots, which we found to be distinctly varied wherein two different AC voltage amplitude regimes, broadly for 10 – 50 mV and 100 – 500 mV AC voltage range.
Explanation of the research
The wide approachability of our synthesis method lies in avoiding expensive precursor salts and eliminating the use of toxic solvents. We have obtained the MAPbBr3 crystals with improved thermal, optical, and dielectric properties that are used in optoelectronic devices, mainly in the applications of solar cells and photodetectors.