Research Area

2D metal halide layered perovskites:

2D metal halide perovskites can be formed by replacing the A-site cations in ABX3 perovskites with long-chain organic spacer cations. Depending on the bonding motif of spacer cations they can be categorized into two types: Ruddlesden-Popper (RP) phase (spacer cation is monodentate type) and (ii) Dion-Jacobson (DJ) phase (spacer cation is bidentate type). These 2D perovskites have recently emerged as an alternative to 3D perovskite nanocrystals since tuning the layer thickness provides bandgap tunability and environmental stability. Due to these properties, these materials are considered potential candidates for next-generation optoelectronic devices (LEDs, Solar cells, etc.).

Semiconductor Quantum Dots (QDs):

Quantum dots (QDs) are semiconducting nanocrystals where the excitons are confined in all three spatial dimensions (i.e. they are zero-dimensional material as compared to the bulk semiconductor). Moreover, QDs are made up of a few numbers of atoms (~200-1000) and an organic layer (surface ligand) with a typical size (2-10 nm) comparable with its bulk exciton Bohr radius. These semiconductor QDs possess unique size-dependent optical and magnetic properties that arise due to the quantum confinement effect. Furthermore, QDs can be engineered to exhibit various other properties, including high quantum yields (brightness), stability, and the ability to undergo surface modifications for specific applications. These exciting properties of semiconductor QDs make them excellent materials for photovoltaic, light-emitting devices, spintronics, and biomedical applications.   

Transition metal ions doped II-VI Quantum Dots:

The un-doped semiconductor QDs have some severe shortcomings, for example, diamagnetic, lack of thermal stability, self-diffusion, self-absorbance, and low quantum yield. However, these shortcomings can be effectively addressed by strategically introducing intentional impurities to modify their properties in a precise and controllable manner. Paramagnetic transition metal (TM) ions doped semiconductor QDs attracted much attention from researchers in the last two decades. These TM ions doped semiconductor QDs pronounced as diluted magnetic semiconductor QDs (DMSQDs) have various technological applications, especially in the field of spintronics, solar cells, and magneto-optics. Doping of TM ions in semiconductors results in orbital exchange interaction between the d-level of the dopant and the sp-levels of the host which can produce a variety of optical and magnetic phenomena.