INSP - UPMC - 4 place Jussieu - 75005 Paris - Barre 22-12, 4e étage, salle 426
Wasim Mir - IISER Pune, India
Doctorant depuis janvier 2017 dans l’équipe Physico-chimie et dynamique des surfaces de l’INSP
One of the major problems of colloidal semiconductors like CdSe is surface defects which trap the charge carriers, severely limiting their electronic, optical and optoelectronic properties. Colloidal lead halide based perovskite nanocrystals (NCs) have been recently established as an interesting class of defect-tolerant nanocrystals with scope of excellent performance in optoelectronic devices. Key factors attributed to their remarkable properties is unique electronic band structure and strong spin orbit coupling leading to nearly trap free (defect tolerant) nature of these colloidal semiconductors. Based upon these factors newer material have been explored for superior optical and transport properties. In this talk, I will be presenting the recent achievements in optical and transport properties in colloidal lead halide based perovskites, anion exchange and scope of doping to tune the optical properties and brief insights about newer materials like colloidal thallium halides. The crucks of talk will be based upon their unique electronic band structure. Some interesting properties related to these materials include 90% PL quantum efficiency with narrow spectral width without any surface modification, reduced PL blinking, negligible FRET/self-absorption, low threshold for lasing and a high carrier mobility within a NC using terahertz spectroscopy.
1. Swarnkar, A. ; Chulliyil, R. ; Ravi, V. K. ; Irfanullah, M. ; Chowdhury, A. ; Nag, A. Colloidal CsPbBr3 Perovskite Nanocrystals : Luminescence Beyond Traditional Quantum Dots. Angew. Chem. Int. Ed. 2015, 54 , 15424-15428.
2. Mir, J. M. ; Rao, M. J. ; Das, S. ; Nag, A. Colloidal Mn-Doped Cesium Lead Halide Perovskite Nanoplatelets. ACS Energy Lett. (In communication)
3. Swarnkar, A. ; Marshall, A. R. ; Sanehira, E. M. ; Chernomordik, B. D. ; Moore, D. T. ; Christians, J. A. ; Chakrabarti, T. ; Luther, J. M. Quantum Dot-Induced Phase Stabilization of Alpha-CsPbI3 Perovskite for High-Efficiency Photovoltaics. Science 2016, 354 , 92-95.
4. Yettapu, G. R. ; Talukdar, D. ; Sarkar, S. ; Swarnkar, A. ; Nag, A. ; Ghosh, P. ; Mandal, P. Terahertz Conductivity within Colloidal CsPbBr3 Perovskite Nanocrystals : Remarkably High Carrier Mobilities and Large Diffusion Lengths. Nano Lett. 2016, 16 , 4838-4848.