Exploring Charge Transport across Organic Molecular Junctions and Perovskite Halide Crystals

Abstract

The present thesis, quotExploring charge transport across organic molecular junctions and perovskite halide crystals,quot mainly focuses on charge transport studies across the materials. We have used various methodologies to understand the charge transport phenomenon across organic molecular junctions and halide perovskite crystals. For the case of molecular junctions, we have used transport modeling techniques to investigate the charge transport phenomenon across various protein-based molecular junctions. Our findings here reveal the transport mechanism across bacteriorhodopsin-based molecular junctions under external stimuli and also studied the modulation in the conductance under external stimuli by calculating several transport parameters such as conductance, energy barrier, and coupling strength. We could also find the limiting factor for various external stimuli, such as various forces applied at the AFM tip and different humidity values across bacteriorhodopsin molecular junctions. Utilizing several transport modeling techniques, we found a suitable transport model for various protein-based molecular junctions, including bacteriorhodopsin, myoglobin, and azurin, that contain various prosthetic groups. We have also studied molecular structural relation with the electronic transport across terthiophene-based molecular junctions by considering several factors that affect the electron transport across terthiophene derivatives using density functional theory (DFT) and validated with a non-equilibrium Green s function (NEGF) approach. newlineFor the case of charge transport studies across perovskite halide crystals, we have synthesized MAPbBr3 crystals at room temperature using the solution-grown method. The structural, thermal, and optical characterizations were done using X-ray diffraction method, thermogravimetry analysis, and UV-Vis spectroscopy analysis, respectively. The electrical characterization was done using impedance spectroscopy and current response with various applied bias voltages. From the electrical charact