Yulia Gromova- PhD
- Researcher at Trinity College Dublin
Yulia Gromova
- PhD
- Researcher at Trinity College Dublin
About
26
Publications
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225
Citations
Introduction
Current institution
Publications
Publications (26)
Quantum dots (QDs) have been envisaged as very promising materials for the development of advanced optical sensors. Here we report a new highly porous luminescent material based on colloidal QDs for potential applications in optical sensing devices. Bulk flower-like porous structures with sizes of hundreds of microns have been produced by slow dest...
Here we report investigation of red-shifted defect photoluminescence observed in two-dimensional colloidal cadmium selenide nanoplatelets. We used absorption, photoluminescence and photoluminescence excitation measurements to show that red-shifted photoluminescence bands are related directly to nanoplatelets and may originate from surface imperfect...
The efficient and sensitive detection of pathogenic microorganisms in aqueous environments such as water used in medical applications, drinking water, and cooling water of industrial plants requires simple and fast methods suitable for multiplexed detection such as flow cytometry (FCM) with optically encoded carrier beads. For this purpose, we comb...
Colloidal ternary quantum dots of AgInS2 and AgInS2/ZnS were synthesized in water in the presence of mercapto alkyl carboxylic acid. Selective size separation of AIS and AIS/ZnS hydrophilic nanoparticles was performed as well as the ligand exchange by thiolated methoxypolyethylene glycol molecules having an amphiphilic nature. The influence of nano...
Magnetic circular dichroism (MCD) spectra were measured for colloidal CdSe/CdS core–wing nanoplatelets (NPLs). MCD spectra of CdSe cores demonstrate well resolved features which could be attributed to excitonic transitions from heavy hole, light hole and split-off sublevels. A1/D0, B0/D0 MCD characteristic terms were determined. The values of A1/D0...
Magnetic, optical, and structural properties of superparamagnetic CoFe2O4 nanoparticles (MNPs), both isolated and in aggregates, are investigated by magnetic circular dichroism (MCD) spectroscopy. The MCD signal for MNPs is more than an order of magnitude greater than the signal for organic molecules, therefore, making this technique a very sensiti...
Energy transfer in hybrid structures based on colloidal quantum dots of CdSe/ZnS and molecules of tetra(p-trimethylamino)phenylporphin formed in polyethylene terephthalate track membranes is considered. A physical model for the formation of these hybrid structures is proposed, and the distribution of structure components in the near-surface layer o...
Luminescence and photoelectric properties of hybrid structures based on CdSe/ZnS quantum dots (QDs) and multilayer graphene have been investigated. A correlation between the luminescence quantum yield of QDs and their photoelectric properties in hybrid structures is established. It is shown that a decrease in the QD luminescence quantum yield due t...
Photoinduced changes in luminescent and photoelectrical properties of the hybrid structure based on CdSe/ZnS QDs and multilayer graphene nanobelts were studied. It was shown that an irradiation of the structures by 365 nm mercury line in doses up to 23 J led to growth of QD luminescent quantum yield and photocurrent in the QD/graphene structures. T...
Photoinduced dissociation of surface complexes of CdSe/ZnS quantum dots with azo-dye 1-(2- pyridylazo)-2-naphthol (PAN) was investigated. It was shown that the Förster resonance energy transfer contributes in the complexes photodissociation rate, which depends on resonance condition between electronic levels of donor (quantum dots) and acceptor (az...
We report on the enhancement of the electrical photoresponse in a hybrid structure composed of multi-layer graphene flakes covered by a layer of CdSe/ZnS quantum dots (QDs) and placed between metal electrodes. The rate of the photoexcitation energy transfer from QDs to graphene, (0.5–2)x10^9 s^-1 which controls the photoelectrical response of the s...
Fabrication of novel micron-scale structures based on multi-layer graphene and quantum dots (QD) hybrids is presented. Two types of CdSe/ZnS (core/shell) QDs with diameters of 5.3 and 2.5 nm and photoluminescence peaks at 630 and 530 nm, respectively, were used. The photoresponse for illumination by a 473 nm wavelength laser was found to change pol...
In this work we demonstrate a preparation technique for hybrid Single Walled Carbon Nanotube - Quantum Dot (SWCNT-QD) photosensors. We investigated photogating effect, fast and slow photoresponse mechanisms observed in the response. The photoresponse of the device depends on the thickness of QDs and gate voltage, also how the photoresponse can be f...
We report on the formation of photoactive hybrid structures based on multilayer graphene nanobelts and CdSe/ZnS quantum dots (QDs) on Pt microelectrodes. We have found that heat treatment in mild conditions enhances rate of electrical photoresponse of the hybrid structures due to elimination of long-lived charge traps. We also show that the electri...
This paper demonstrates photoinduced dissociation of complexes of CdSe/ZnS quantum dots with molecules of 1,2-pyridylazo naphthol under the action of external radiation of various spectral compositions and powers. It is found that energy transport from the quantum dots to the azo dye molecule appreciably contributes to the dissociation rate of the...
Hybrid structures based on CdSe/ZnS quantum dots and porphyrin molecules with effective energy transfer were formed in samples of polymer track pore membrane. It was observed that energy transfer efficiency depends on quantum dot size and correlates with overlapping integral between quantum dot photoluminescence and porphyrin absorption spectra inh...
We present technique of obtaining complex hybrid structures combining the multi-walled carbon nanotubes or multi-layer graphene and luminescent hydrophobic semiconductor core/shell quantum dots CdSe/ZnS. As a result, a formation of quantum dot decorated carbon nanotubes and graphene films is evidenced by 2D microluminescence and micro-Raman mapping...
We investigate electrical photoresponse of multilayer graphene decorated with CdSe/ZnS quantum dots. It was found that photoresponse of these hybrid structures depends on quantum dot photoluminescence quantum yield. We demonstrate in uence of external factors (light exposure and treatment with ammonia vapors) on photoluminescence quantum yield of q...
In present study complexes between non-toxic ZnSe/ZnS quantum dots and chlorin e6 molecules that are widely used as photosensitizers in photodynamic therapy were formed. It was found that in aqueous solution cationic ZnSe/ZnS quantum dots and chlorin e6 formed stable complexes that exhibit efficient photoexcitation energy transfer from quantum dots...
Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of intera...
The photoluminescence response of semiconductor CdSe/ZnS quantum dots embedded in a borosilicate porous glass matrix to exposure to ammonia vapor is investigated. The formation of surface complexes on the quantum dots results in quenching of the photoluminescence and a shortening of the luminescence decay time. The process is reversible, desorption...
We prepared hybrid structures based on CdSe/ZnS quantum dots and organic azo-dyes and porphyrin molecules embedded into polymer track pore membranes. The quenching of the quantum dot's photoluminescence and the shortening of its decay time, accompanied in the latter case by a porphyrin sensitized photoluminescence, present a clear evidence of the e...
We studied the optical properties of poly(ethylene terephthalate) ion track membranes of 1.5, 0.5 and
0.05 µm pores impregnated with luminescent semiconductor CdSe/ZnS nanocrystals of different
diameters (2.5 and 5 nm). The nanocrystals were embedded from their colloidal solutions in
toluene by the immersion of a membrane in a colloidal solution. L...
Questions
Questions (3)
I have a unit cell of CoFe2O4 of 56 atoms, but I want to reduce it to a primitive cell with 14 atoms. I try to use "Niggli-reduced cell" options in Vesta but I have trouble with the interpretation of results. At first, I curious why in the log window are marked positions of only 9 atoms, but when I export data to .vasp there are all 14 atoms but without atoms titles. And the second problems - I do not understand why coordinates of atoms in Niggli-cell do not match with coordinates of same atoms in common unit cell.
I would be really grateful for the explanation of these things and any tips about using Vesta for primitive cell construction.
Thanks.
Hello!
I have a problem with Na2S·9H2O. A half of year ago it was a white wet powder (like a melted sugar) and now, when I have opened the jar I have found there a black liquid with a gray precipitate. What is happen with it and is it possible to repare it?
Thanks.
Which kind of hood is better to use - with a horizontal or vertical stream? And I am worrying about possibility of vibration from air pumping motor. Could it be a problem for the film deposition?
Thanks
