Title : The dynamic and evolving world of Quantum Dots
Abstract:
A quantum dot (QD) is a semiconductor nanostructure that confines the motion of conduction band electrons, valence band holes, or excitons (bound pairs of conduction band electrons and valence band holes) in all three spatial directions. The quantum confinement results in appearance of discrete energy levels leading to existence of multiple exciton generation (MEG), tunable band gap and size dependent photoluminescence in quantum dots (QDs). These semiconducting marvels have been prepared by a variety of material combinations, such as, group II and group VI, group III and group V, and most recently from carbon. We have been able to synthesize a variety of QD such as CdSe, CdS, CdSe-CdS, and Carbon and successfully tested their applications in third generation solar cells. By using only CdSe QD on the photo anode, we have been able to achieve a maximum Voc of 1.51 V. In another study, upon using sequential deposition of different QD we were able to achieve eight times higher efficiency than its corresponding dye sensitized solar cell (DSSC). Furthermore, the use of C QD in co-sensitized type device resulted in almost three times increase in efficiency than the DSSC. Overall, QD can serve a much wider purpose in establishing better useful devices for everyday applications. Quite recently, we have started working on using the QD to develop in-door photovoltaic based systems.
