Dmitriy Dovzhenko of the Laboratory of Nano-Bioengineering of NRNU MEPhI successfully defended PhD thesis in physics and mathematics

Dmitriy Dovzhenko, research engineer of the Laboratory of Nano-Bioengineering (LNBE), NRNU MEPhI, has successfully defended his PhD thesis on Photophysical Characteristics of Hybrid Systems Based on Semiconductor Quantum Dots and Photonic Crystals of Porous Silicon. The PhD research project, supervised by Professor Alexander A. Chistyakov, PhD, DSci, has been performed in the framework of LNBE's large-scale research in hybrid nanomaterials.

Systems consisting of photonic crystals with embedded luminophores are interesting in that the photonic crystal can not only affect the propagation of electromagnetic waves, but also directly change the luminophore's emissive characteristics, which is expressed in enhancement of luminescence and variation of the spectral, spatial, and temporal parameters. The key issue of experimental studies on hybrid luminescent systems of this type is to determine the contribution of each effect into the variation of luminescence characteristics; this will allow the efficiency of the systems to be substantially increased. Estimating the contributions of the spatial redistribution of luminescence determined by the photonic crystal structure and the Purcell effect into the enhanced photoluminescence of quantum dots incorporated in one-dimensional photonic crystals of porous silicon was one of the main objectives of the PhD research project.

In addition to the theoretical interest, the possibility of controlling the emitter's relaxation time by selecting the parameters of the photonic crystal has important potential applications; this can be used to design new generations of both light-emitting devices and sensors. Therefore, the goal of the PhD research was not only to study the properties of the hybrid systems, but also to optimize their structure in terms of practical applications in these two fields. For this purpose, Dmitriy has analyzed how the conditions of fabrication of photonic crystals (obtained by etching) influence the luminescence characteristics of the hybrid system and developed a mathematical model describing this dependence. The model has been shown to closely fit experimental data and can be used for obtaining photonic crystals with desired characteristics.

The author has published 14 papers on the subject of his PhD thesis, many of them in top-rated international journals. Some results of this research are already used in practice: the basic effects studied by Dmitriy are employed in developing biosensors for detection of serum markers of socially important diseases.

During the defense of the thesis, all speakers spoke highly of the research and its results; even the official opponents gave more favorable comments than criticisms. The Thesis Council unanimously voted for granting Dmitriy the PhD degree in physics and mathematics.

Dmitriy's colleagues heartily congratulate him on this achievement and wish him many more success!

Contacts:

Dmitriy S. Dovzhenko, research engineer (dovzhenkods@gmail.com)

Maria G. Korenkova, director of external relations (MGKorenkova@mephi.ru)

Laboratory of Nano-Bioengineering, Moscow Engineering Physics Institute
31 Kashirskoe shosse, 115409 Moscow, Russian Federation
http://www.lnbe.mephi.ru/en

 
 
 
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