The tunable light emission and quantum confinement effects in the semiconductor CQDs are well understood in terms of basic quantum mechanics. Since the charge in the CQDs governs their optical properties, high resolution optical spectroscopic techniques enable us to understand the charge distribution and recombination pathways. We exclusively use the photoluminescence spectroscopy to characterize novel nanocrystals from ensemble to single particle level. Electronic coupling among the CQDs is one of our favourite topic of study especially the coupling mechanisms (resonance energy transfer, barrier effect on tunelling of exciton) in fused dimers and multi excitonic configuration in them.

Single Paricle Spectroscopy and Microscopy

Single molecule methods have been revolutionized the field of optical spectroscopy of QDs. Using single molecule optical spectroscopy we can explore the digital blinking, photon antibunching and so many important aspects of QDs which get masked in ensemble studies. We have used single molecule spectroscopy to explore the orientation polarization relationship in seeded nanorods, nanoscale imaging of excitons, modified recombination in quantum molecules in transition from quantum dots. Our recent focus in this field is low temperature high resolution spectroscopy, where we are able to resolve spectral width down to <1meV for a single QD, with a vision to resolve the exciton fine structure.

Calculation of Electronic Structure in QDs

We use Comsol Multiphysics to calculate the electronic properties such as potential energy landscape, energy and delocalization of exciton, multiexcitoni of colloidal quantum dots.