Dependence of optical, luminescent, and emission properties of carbon nanoparticles on pH of medium

S. A. Kazaryan, V. N. Nevolin, G. G. Kharisov, N. F. Starodubtsev

The effect of the medium’s pH on the optical, luminescent and emission parameters of various types of carbon nanoparticles (CNPs) in aqueous solutions was studied. It was shown that the parameters of the optical absorption (Ab) and photoluminescence (PL) spectra, as well as the magnitude and stability of the quantum yield of emission (QYE), significantly depend on the medium’s pH, the properties of the functional groups (FG) and the carbon cores of CNPs. The main contribution to the change in these parameters of CNPs is made by the FG of the particles. The strongest and most vivid change in the optical and luminescent parameters of all types of CNPs is observed at the pH range of aqueous solutions of 10 – 13 and 0.1 – 3. The CNPs parameters changing  is closely related to the protonation and deprotonation processes of the FG of particles of CNPs – COOH, CNPs – OH and CNPs – NH2 types, as well as to photostimulated processes. With the change of the pH of CNPs medium, in the Ab and PL spectra the growth and the decline of the absorption and emission, the appearance and disappearance of the absorption bands, the change of symmetry and width contours and bathochromic and hypsochromic shift of the absorption and PL bands often were observed. It is shown that the mechanism of the effect of the nitrogen and oxygen heteroatoms of the functional groups on PL and QYE is associated with complex electrons interactions of the unshared pairs of N and O atoms with the p-system of aromatic rings of the CNPs carbon core.

Keywords: luminescence of nanoparticles, fluorescence of nanoparticles, luminescence of quantum dots, carbon nanoparticles, carbon quantum dots, emission quantum yield of the nanoparticles, synthesis of carbon nanoparticles and quantum dots.

DOI: 10.30791/1028-978X-2020-5-5-22

Kazaryan Samvel — Lebedev Physical Institute of Russian Academy of Science (Leninsky prospect 53, 119991, Moscow, Russia), PhD (Phys-Math), head of department, specialist in the field of luminescence of semiconductors, diamonds, nanosized carbons, as well as technology for the synthesis of nanoporous materials and electrochemical supercapacitors. E-mail: skazaryan.fian@gmail.com.

Nevolin Vladimir — Lebedev Physical Institute of Russian Academy of Science (Leninsky prospect 53, 119991, Moscow, Russia), Dr Sci (Phys- Math), professor, assistant to Director for financial and economic affairs and innovation activities, specialist in the field of physics of thin-film structures. E-mail: nevolin@sci.lebedev.ru.

Kharisov Gamir — Lebedev Physical Institute of Russian Academy of Science (Leninsky prospect 53, 119991, Moscow, Russia), leading process engineer, specialist in quantum electronics, semiconductor lasers, optics, nanosized materials technology, and electrochemical supercapacitors. E-mail: xarisow@yandex.ru.

Starodubtsev Nikolai — Lebedev Physical Institute of Russian Academy of Science (Leninsky prospect 53, 119991, Moscow, Russia), PhD (Phys-Math), head of department, specialist in quantum electronics, nanosized materials technology. E-mail: nfstaro@gmail.com.

Reference citing

Kazaryan S.A., Nevolin V.N., Kharisov G.G., Starodubtsev N.F. Issledovanie zavisimosti opticheskih, lyuminescentnyh i emissionnyh svojstv uglerodnyh nanochastic ot pH sredy [Dependence of optical, luminescent, and emission properties of carbon nanoparticles on pH of medium]. Perspektivnye Materialy — Advanced Materials (in Russ), 2020, no. 5, pp. 5 – 22. DOI: 10.30791/1028-978X-2020-5-5-22

Damage and deformation effects in the surface layers
of the copper and copper – gallium alloy under pulse irradiation in plasma focus device

I. V. Borovitskaya, V. A. Gribkov, A. S. Demin, N. A. Yepifanov,
S. V. Latyshev, S. A. Maslyayev, Ye. V. Morozov,
V. N. Pimenov, I. P. Sasinovskaya,
G. G. Bondarenko, A. I. Gaydar, М. Scholz

The results of experiments on the irradiation of copper and Cu-10% Ga alloys (wt. %) by pulsed flows of deuterium plasma (DP) and deuterium ions (DI) carried out in the Plasma Focus (PF) device are presented. The technique of experiments and studies is described. We studied the damage and deformation effects in the surface layers of these materials after irradiation of each of them in two modes. In one case, irradiation was carried out by a pulsed deuterium plasma with a power density qpl = 107 W/cm2 and a pulse duration of tpl = 100 ns. In another case, the pulsed fluxes of deuterium ions simultaneously acted at qi = 108 – 1011 W/cm2, ti = 50 ns and dense deuterium plasma at qpl = 108 – 109 W/cm2, tpl  = 100 ns. Under a less hard irradiation regime (only by plasma flows) the damage to both materials is close to each other: in the melted surface layer (SL) there are a wavy surface, craters, micropores. Under the influence of thermal stresses the plastic deformation was observed in the alloy PS, while in pure copper this process was not observed under this irradiation mode. Damage to both materials in a more hard irradiation regime with the pulsed fluxes of deuterium ions and deuterium plasma is enhanced and accompanied by erosion of the PS and the possibility of re-deposition of micro-particles of the elements included in the composition of the functional materials of the PF chamber onto the irradiated surface. The most significant damage is observed in the PS of the Cu-10% Ga alloy, which in addition to powerful beam-plasma flows also experienced shock-wave action. Under this irradiation regime of the compared materials plastic deformation occurred in the PS of each of them. In pure copper (at q = 108 – 109 W/cm2) the plastic deformation was observed in separate local micro-volumes of PS, and in the copper-gallium alloy at q = 1010 – 1011 W/cm2 this process was implemented for the entire irradiated PS. In this case, plastic deformation was carried out both under the influence of shock-wave mechanical loads and under the influence of thermal stresses.

Keywords: pulsed flows, deuterium plasma, deuterium ions, plasma focus, damage, copper-gallium alloy, plastic deformation.

DOI: 10.30791/1028-978X-2020-5-23-37

 

Borovitskaya Irina — Baikov Institute of Metallurgy and Material Science RAS (49, Leninskii Prospect, Moscow 119334, Russia), PhD, senior research worker. E-mail: symp@imet.ac.ru.

Gribkov Vladimir — Baikov Institute of Metallurgy and Material Science RAS (49 Leninskii Prospect, Moscow 119334, Russia), DrSci (Phys-Math), prof, principal research worker. E-mail: gribkovv@rambler.ru.

Demin Aleksandr — Baikov Institute of Metallurgy and Material Science of RAS (49 Leninskii Prospect, Moscow 119334, Russia), research worker. E-mail: casha@bk.ru.

Epifanov Nikita — Baikov Institute of Metallurgy and Material Science RAS (49 LeninskiiProspect, Moscow 119334, Russia), junior researcher; National Research University Higher School of Economics (20  Myasnitskaya, Moscow 101000, Russia), postgraduate student. E-mail: mophix94@gmail.com.

Latyshev Sergei — Baikov Institute of Metallurgy and Material Science of RAS (49 Leninskii Prospect, Moscow 119334, Russia), PhD, senior research worker; Moscow Technical University of Communications and Informatics (8a, Aviamotornaya Street, Moscow 111024, Russia), associate professor. E-mail:
latyshevsv@rambler.ru.

Maslyaev Sergey — Baikov Institute of Metallurgy and Material Science RAS (49 Leninskii Prospect, Moscow 119334, Russia), PhD, senior research worker. E-mail: maslyaev@mail.ru.

Morozov Evgenii — Baikov Institute of Metallurgy and Material Science of RAS (49 Leninskii Prospect, Moscow 119334, Russia), research worker. E-mail: lieutenant@list.ru.

Pimenov Valeriy — Baikov Institute of Metallurgy and Material Science RAS (49 Leninskii  Prospect, Moscow 119334, Russia), Dr Sci (Phys-Math), head of laboratory. E-mail: pimval@mail.ru.

Sasinovskaya Irina — Baikov Institute of Metallurgy and Material Science RAS (49 Leninskii Prospect, Moscow 119334, Russia), research worker. E-mail address: porfirievna@mail.ru.

Bondarenko Gennadii — National Research University Higher School of Economics (20 Myasnitskaya, Moscow 101000, Russia), Dr Sci (Phys-Math), professor. E-mail: gbondarenko@hse.ru.

Gaidar Anna — Research Institute of Advanced Materials and Technologies (12 Malaya Pionerskaya, Moscow 115054, Russia), PhD, senior research worker.

Scholz Marek — Institute of Nuclear Physics (Radzikowskogo Str.152, 31-342 Krakow, Poland), PhD, specialist in dense magnetized plasma and radiation transfer physics.

Reference citing

Borovitskaya I.V., Gribkov V.A., Demin A.S., Yepifanov N.A., Latyshev S.V., Maslyayev S.A., Morozov Ye.V., Pimenov V.N., Sasinovskaya I.P., Bondarenko G.G., Gaydar A.I., Scholz М. Povrezhdaemost' i deformacionnye effekty v poverhnostnyh sloyah medi i splava sistemy med' – gallij pri impul'snom obluchenii v ustanovke Plazmennyj fokus [Damage and deformation effects in the surface layers of the copper and copper – gallium alloy under pulse irradiation in plasma focus device]. Perspektivnye Materialy — Advanced Materials (in Russ), 2020, no. 5, pp. 23 – 37. DOI: 10.30791/1028-978X-2020-5-23-37

 

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