Giant Stokes Shifts in AgInS2 Nanocrystals with Trapped Charge Carriers

• Published in: Journal of physical chemistry. C 2019-07, Vol.123 (26), p.16430-16438
• Main Authors: Baimuratov, Anvar S, Martynenko, Irina V, Baranov, Alexander V, Fedorov, Anatoly V, Rukhlenko, Ivan D, Kruchinin, Stanislav Yu
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.9b03537

Nanocrystals of AgInS2 demonstrate giant Stokes shifts ∼1 eV, the nature of which is still not clearly understood. We propose a theoretical model of this phenomenon, bringing together several different mechanisms previously considered only separately. We take into account the contribution of the electron–electron interaction with the hybrid density functional theory, as well as the renormalization of the energy spectrum due to the electron–phonon coupling. Furthermore, we consider the presence of at least one point defect responsible for hole trapping and the formation of a localized polaron state. Our numerical simulations show that photoluminescence due to the recombination of a nontrapped electron and a trapped hole results in the giant Stokes shift in AgInS2 nanocrystals, which is in close agreement with the recent experimental results.