Department of Chemistry
Indian Institute of Technology Delhi

Quantum dots for light energy harvesting and conversion

Dr. K George Thomas
School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, 695 016, India. E-mail:

Date: April 17th 2018 (Tuesday)
Time: 12:00 PM
Venue: Committee Room, Chemistry Department, 6th Floor

Unique properties of semiconductor nanocrystals include their ability to generate long lived excitons, transport charge carriers with high mobility, and reduce the number of interparticle hops required for electron extraction. The first part of the talk will provide an overview on various approaches adopted in our laboratory for tuning the energy as well as electron transfer processes in II-VI and III-V semiconductor quantum dots. Photoinduced energy and electron transfer from QDs to surface bound molecules are investigated using steady state as well as time resolved absorption and emission spectroscopic techniques. Compared to CdSe, the hole trap states are buried deep in InP which prevents the rapid recombination of charge separated states. Our results indicate that InP is a versatile material for light harvesting and charge transport applications, meeting various photophysical and biological requirements. Excitons in heterojunction nanoscale systems (semiconductor-semiconductor and semiconductor-metal) possess novel properties that are fundamentally different from those of individual components. Examples of designing various types of heterojunctions and their charge transfer properties will be discussed in the second part of the presentation.

  1. A. Thomas, K. Sandeep and K. George Thomas (submitted. 2018)
  2. A. Thomas, P. V. Nair and K. George Thomas, J Phys Chem C, 2014, 118, 3838–3845.
  3. K. B. Subila, K. Sandeep, E. M. Thomas, J. Ghatak, S. M. Sivaprasad and K. George Thomas, ACS Omega, 2017 2, 5150–5158.
  4. K. B. Subila, G. K. Kumar, S. M. Shivaprasad and K. George Thomas, J Phys Chem Lett, 2013, 4, 2774-2779.

All are cordially invited to attend.
Convener (Seminars)