Photophysics of Titania Nanoparticle/Quantum Dot Hybrid Structures
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ANOPHOTONICS
Photophysics of Titania Nanoparticle/Quantum Dot Hybrid Structures1 E. P. Kolesovaa, *, F. M. Safina, V. G. Maslova, A. Dubavika, Y. K. Gun’kob, and A. O. Orlovaa a
ITMO University, St. Petersburg, 197101 Russia b Trinity College, Dublin 2, Ireland * e-mail: [email protected]
Received January 18, 2020; revised January 18, 2020; accepted April 20, 2020
Abstract—The efficiency of the electron transfer in hybrid structures based on quantum dots of different architectures was studied. Electron transfer efficiency was estimated by two independent methods from the side of the electron donor (quantum dot) and acceptor (Titania nanoparticles). Structures based on core CdSe QDs with small diameter demonstrate the highest efficiency of electron transfer and ROS generation. The presence of the dark fraction of QDs in the ensemble reduces the functionality of hybrid structures and limits their practical applicability. Keywords: hybrid structures, quantum dots, luminescence quenching, electron transfer, reactive oxygen species DOI: 10.1134/S0030400X20080160
INTRODUCTION The physics of nanoscale materials is one of the most rapidly developing areas of theoretical and experimental solid state physics. The formation of hybrid structures consisting of several types of nanostructured objects has been the main direction of nanotechnology development in recent years [1]. This interest is caused by the possibility to combine the unique properties of the components that make up their composition, which allows for the creation of multifunctional systems with unique physical properties. Luminescent quantum dots (QDs) of cadmium selenide are traditional inorganic luminophore with well-studied properties [2]. Structures based on titanium dioxide nanoparticles (TiO2 NPs) and QDs can combine the high photocatalytic activity of TiO2 with the ability of QDs to absorb radiation in a wide spectral range and act as an effective electron donor. The band structure of QDs and Titania nanoparticles allows for highly efficient photoinduced electron transfer from QDs to TiO2 NPs [3], which allows for the formation of structures effectively generating reactive oxygen species (ROS) under visible light. Such structures are promising systems for the treatment of bacterial infections and can solve the problem of antibiotics resistance [4]. Today there are lots of papers describing TiO2 NPs/QDs structures; the major part 1 The 2nd International School-Conference for young researchers
“Smart Nanosystems for Life,” St. Petersburg, Russia, December 10–13, 2019.
of them is related to photovoltaics [5, 6], and only a few papers describe these structures as antimicrobial agents. Lack of a model describing how ROS generation efficiency depends on the structure’s parameters and electron transfer efficiency is the main reason for this imbalance. In this work, we have studied electron transfer efficiency and ROS generation efficiency for 3 types of multilayered TiO2 NPs/QDs hybrid structures, based on cadmium selenide QDs with different core and
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