Role of Surface Reduction in the Formation of Traps in n-Doped II–VI Semiconductor Nanocrystals: How to Charge without Reducing the Surface
Indy du Fossé a, Stephanie ten Brinck b, Ivan Infante b c, Arjan J. Houtepen a
a Delft University of Technology (TU Delft), The Netherlands, Van der Maasweg, 9, Delft, Netherlands
b Department of Theoretical Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
c Istituto Italiano di Tecnologia (IIT), Genova, Italy, Via Morego, 30, Genova, Italy
nanoGe Fall Meeting
Proceedings of nanoGe Fall Meeting19 (NGFM19)
#NCFun19. Fundamental Processes in Semiconductor Nanocrystals
Berlin, Germany, 2019 November 3rd - 8th
Organizers: Ivan Infante and Jonathan Owen
Poster, Indy du Fossé, 394
Publication date: 18th July 2019

The efficiency of nanocrystal (NC)-based devices is often limited by the presence of surface states that lead to localized energy levels in the bandgap. Yet, a complete understanding of the nature of these traps remains challenging. Although theoretical modeling has greatly improved our comprehension of the NC surface, several experimental studies suggest the existence of metal-based traps that have not yet been found with theoretical methods. Since there are indications that these metal-based traps form in the presence of excess electrons, we have used density functional theory (DFT) calculations to study the effects of charging II–VI semiconductor NCs with either full or imperfect surface passivation. It is found that charge injection can lead to trap-formation via two pathways: metal atom ejection from perfectly passivated NCs or metal–metal dimer-formation in imperfectly passivated NCs. These results shed light on how L-type amine ligands can passivate NCs, which may also be relevant for charge neutral NCs, where photoexcited electrons could get trapped in metal-based traps. This work has clear implications for n-doping II–VI semiconductor NCs without introducing surface traps due to metal ion reduction.

A.J.H. acknowledges support from the European Research Council Horizon 2020 ERC Grant 678004 (Doping on Demand). I.I. acknowledges The Netherlands Organization of Scientific Research (NWO) for financial support through the Innovational Research Incentive (Vidi) Scheme (Grant 723.013.002). The computational work was carried out on the Dutch national e-infrastructure with the support of the SURF Cooperative.

© Fundació Scito
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info