scholarly journals Синтез и фотолюминесценция наноразмерных структур на основе сульфидов цинка, кадмия и марганца в полиакрилатной матрице

2020 ◽  
Vol 54 (12) ◽  
pp. 1321
Author(s):  
А.А. Исаева ◽  
В.П. Смагин
Keyword(s):  
Optical Radiation ◽  
Energy Levels ◽  
Radiation Energy ◽  
Photoluminescence Excitation ◽  
Photoluminescence Spectra ◽  
Interband Transitions ◽  
Nanoscale Structures ◽  
Semiconductor Structures ◽  
Recombination Processes ◽  
Zinc Cadmium

Photoluminescence of nanoscale structures based on zinc, cadmium and manganese sulfides depending on the conditions of synthesis and doping in the medium (poly)methylmethacrylate (PMMA). Photoluminescence excitation is associated with interband transitions of electrons in the semiconductor structures, absorption of optical radiation energy by defects in the crystal structure, as well as with the transfer of energy to the excited energy levels of Mn2+ ions. Luminescence occurs as a result of recombination processes at the levels of defects in the structure of the surface of particles and 4T1 → 6A1 transitions between the proper energy levels of Mn2+ ions. Based on changes in the photoluminescence spectra and photoluminescence excitation of PMMA/(Zn,Cd,Mn)S compositions, assumptions are made about the structure of particles. It is shown that their photoluminescence is affected by the distribution of Mn2+ ions in the structure of layers and on the surface of particles.

scholarly journals Фотолюминесценция композитов полиметилметакрилат / [(Zn,Cd)S : Mn,Cu,Eu]

2021 ◽  
Vol 47 (16) ◽  
pp. 46
Author(s):  
В.П. Смагин ◽  
А.А. Исаева
Keyword(s):  
Energy Transfer ◽  
Methyl Methacrylate ◽  
Interband Transition ◽  
Energy Levels ◽  
Structural Defects ◽  
Nanoscale Structures ◽  
Semiconductor Structures ◽  
Electron Transitions ◽  
Recombination Processes ◽  
Defect Levels

Nanoscale structures based on zinc and cadmium sulfides doped with Mn, Cu, and Eu ions were synthesized by the method of emerging reagents in a polymerizing medium of methyl methacrylate. The broadband photoluminescence of the compositions is associated with recombination processes at the defect levels of semiconductor structures. Narrow photoluminescence bands occur during electron transitions between the energy levels of Eu3+ ions. The excitation of photoluminescence occurs as a result of the interband transition and electron transitions to the levels of structural defects, as well as during self-absorption and energy transfer to the levels of Eu3+ ions.

scholarly journals Optical Absorption and Photoluminescence in the Spherical InP/InSb/InP Core/ shell/ shell Nano Structure

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Incident Light ◽  
Energy Levels ◽  
Charge Carriers ◽  
Oscillator Strengths ◽  
Core Shell ◽  
Photoluminescence Spectra ◽  
Interband Transitions ◽  
Nano Structure ◽  
Resonant Character ◽  
The One

The one particle states of charge carriers are considered in InP/InSb/InPcore/shell/shell spherical quantum nano structure at the regime of strong quantization. The results of numerical calculations for the values of the energy of charge carriers for different values of the thickness of the quantizing layer of InSb are presented. The calculations were performed with allowance for the Kaned is persion for electrons and light holes in the InSb layer. The dependence of the number and position of the energy levels of charge carriers in the quantizing layer of InSb on the width of the well (layer thickness) is shown. The dependence of the absorption coefficient and photoluminescence spectra on the energy of incident light of interband transitions have been investigated. The oscillator strengths and selection rules for these transitions have been obtained. The absorption has a strictly resonant character. By the orbital and azimuthal numbers only diagonal inter band transitions are possible. For the radial number, the transitions between the states with the same radial numbers have the highest intensity

Radiative Recombination in the Cu(In,Ga)Se2 Thin Films Irradiated with Hydrogen Ions

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940033
Author(s):  
O. Borodavchenko ◽  
V. Zhivulko ◽  
M. Yakushev ◽  
M. Sulimov
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Solid Solutions ◽  
Radiative Recombination ◽  
Energy Levels ◽  
Hydrogen Ions ◽  
Photoluminescence Excitation ◽  
Photoluminescence Spectra ◽  
Induced Defects ◽  
Irradiation Induced Defects

The irradiation-induced effects in Cu(In,Ca)Se2 thin films after irradiation with hydrogen ions with dose of [Formula: see text][Formula: see text]cm[Formula: see text] and different energies in the range of 2.5–10[Formula: see text]keV were studied. Irradiated and nonirradiated thin films were investigated by low-temperature (4.2[Formula: see text]K) photoluminescence and photoluminescence excitation methods. The appearance of intense bands at [Formula: see text][Formula: see text]eV and 0.77[Formula: see text]eV in the photoluminescence spectra may be related to radiative recombination on the irradiation-induced defects with deep energy levels in the bandgap of Cu(In,Ca)Se2 solid solutions. A possible nature of these defects and process of radiative recombination are discussed.

scholarly journals Progress on the Synthesis and Application of CuSCN Inorganic Hole Transport Material in Perovskite Solar Cells

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2592 ◽  
Author(s):  
Funeka Matebese ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Hole Mobility ◽  
Cost Effective ◽  
Vital Role ◽  
Hole Transport ◽  
Recombination Processes ◽  
Short Synthesis ◽  
P Type

P-type wide bandgap semiconductor materials such as CuI, NiO, Cu2O and CuSCN are currently undergoing intense research as viable alternative hole transport materials (HTMs) to the spiro-OMeTAD in perovskite solar cells (PSCs). Despite 23.3% efficiency of PSCs, there are still a number of issues in addition to the toxicology of Pb such as instability and high-cost of the current HTM that needs to be urgently addressed. To that end, copper thiocyanate (CuSCN) HTMs in addition to robustness have high stability, high hole mobility, and suitable energy levels as compared to spiro-OMeTAD HTM. CuSCN HTM layer use affordable materials, require short synthesis routes, require simple synthetic techniques such as spin-coating and doctor-blading, thus offer a viable way of developing cost-effective PSCs. HTMs play a vital role in PSCs as they can enhance the performance of a device by reducing charge recombination processes. In this review paper, we report on the current progress of CuSCN HTMs that have been reported to date in PSCs. CuSCN HTMs have shown enhanced stability when exposed to weather elements as the solar devices retained their initial efficiency by a greater percentage. The efficiency reported to date is greater than 20% and has a potential of increasing, as well as maintaining thermal stability.

scholarly journals Radiation Sterilization: Dose Is Dose

2020 ◽  
Vol 54 (s1) ◽  
pp. 45-52
Author(s):  
Joyce M. Hansen ◽  
Niki Fidopiastis ◽  
Trabue Bryans ◽  
Michelle Luebke ◽  
Terri Rymer
Keyword(s):  
Energy Level ◽  
Energy Levels ◽  
Radiation Energy ◽  
Biological Indicators ◽  
High Energy ◽  
Microbial Inactivation ◽  
Radiation Sterilization ◽  
Dose Rates ◽  
Radiation Sources ◽  
Radiation Sterilization Dose

Abstract In the radiation sterilization arena, the question often arises as to whether radiation resistance of microorganisms might be affected by the energy level of the radiation source and the rate of the dose delivered (kGy/time). The basis for the question is if the microbial lethality is affected by the radiation energy level and/or the rate the dose is delivered, then the ability to transfer dose among different radiation sources could be challenged. This study addressed that question by performing a microbial inactivation study using two radiation sources (gamma and electron beam [E-beam]), two microbial challenges (natural product bioburden and biological indicators), and four dose rates delivered by three energy levels (1.17 MeV [gamma], 1.33 MeV [gamma], and 10 MeV [high-energy E-beam]). Based on analysis of the data, no significant differences were seen in the rate of microbial lethality across the range of radiation energies evaluated. In summary, as long as proof exists that the specified dose is delivered, dose is dose.

scholarly journals Solution of the problem of impact elastoplastic deformation of a thin layer of mechanoluminophor using the methods of the dislocation microdynamic theory of plasticity

2019 ◽  
Vol 221 ◽  
pp. 01047
Author(s):  
Konstantin Tatmyshevskiy
Keyword(s):  
Thin Layer ◽  
Optical Radiation ◽  
Strong Electric Field ◽  
Radiation Energy ◽  
Direct Conversion ◽  
Sensing Element ◽  
Optical Signals ◽  
Flexible Polymer ◽  
Basic Equations ◽  
The Mathematical Model

The paper presents the results of numerical simulation of the output optical signals of mechanoluminescent shock sensors. Such sensors operate on the principle of direct conversion of mechanical impact energy into optical radiation energy. The sensing element of such a sensor is a thin layer of phosphor enclosed between two transparent flexible polymer films. The mathematical model of the sensor is based on the process of excitation of the glow centers (activator atoms) in a strong electric field of a moving dislocation. The stress-strain state of the film sensing element under quasi-static uniaxial loading under the action of a single pressure pulse is considered. The analysis of constitutive equations for elasto-plastic deformations and the basic equations of the dynamic theory of dislocations. To calculate the deformation of the sensing element, a microscopic model of an isotropic elastic-plastic medium with hardening is used, according to which the plastic deformation is considered as a result of the movement and multiplication of dislocations, and the hardening is as a result of their partial locking due to the increased density.

Study of the Radiative and Non-Radiative Recombination Processes at Dislocations in Silicon by Photoluminescence and LBIC Measurements

1999 ◽  
Vol 588 ◽  
Author(s):  
S. Pizzini ◽  
S. Binetti ◽  
M. Acciarri ◽  
M. Casati
Keyword(s):  
Radiative Recombination ◽  
Room Temperature ◽  
Light Emission ◽  
Energy Levels ◽  
The Third ◽  
Optical Telecommunications ◽  
Recombination Processes ◽  
Metallic Impurities ◽  
Room Temperature Luminescence ◽  
Dislocation Related Luminescence

AbstractIt is well known that the sharp, room temperature luminescence emission at 1.54 μm from dislocated silicon has set off a great interest for this material in view of its applications in the third window of optical telecommunications. For this reason the dislocation related luminescence in silicon addressed recently a number of investigation aimed at understanding the mechanism of light emission. The problem is still unsolved as most of the experiments done gave contradictory answers to the main questions open, which concern the intrinsic or extrinsic nature of dislocation luminescence and the effect on it of reconstruction, interaction or passivation processes, possibly assisted by metallic or non-metallic impurities.In order to go more insight on the problem, we started a systematic work on CZ silicon, aimed at understanding the properties of dislocation luminescence. The identification of the energy levels involved in the different dislocation PL bands has been obtained.

Exciton and Defect Photoluminescence Signatures in Single Crystal Rubrene

2006 ◽  
Vol 965 ◽  
Author(s):  
Oleg Mitrofanov ◽  
David V Lang ◽  
Christian Kloc ◽  
Theo Siegrist ◽  
Woo-Young So ◽  
...  
Keyword(s):  
Radiative Recombination ◽  
Photoluminescence Spectra ◽  
Photoluminescence Band ◽  
Exciton Dissociation ◽  
Acceptor Center ◽  
Oxygen Related Defect ◽  
Recombination Processes ◽  
Photo Conductivity ◽  
Exciton Recombination ◽  
Related Defect

ABSTRACTRadiative recombination processes provide valuable information about exciton dynamics and allow detection of defects in rubrene crystals. We demonstrate that the photoluminescence spectra of crystalline rubrene reflect exciton dissociation through oxygen-related defects in addition to the direct exciton recombination. The defect-assisted exciton dissociation results in a well-defined photoluminescence band. These defects play an important role in charge transport. Dark- and photo-conductivity is higher in rubrene crystals with a large density of the defects. The observations strongly suggest that the oxygen-related defect forms a bandgap state and acts as an acceptor center in crystalline rubrene.

scholarly journals Carrier recombination in sonochemically synthesized ZnO powders

2017 ◽  
Vol 35 (1) ◽  
pp. 211-216 ◽  
Author(s):  
M.I. Zakirov ◽  
O.A. Korotchenkov
Keyword(s):  
Surface Defects ◽  
Sonochemical Method ◽  
Photoluminescence Spectra ◽  
Carrier Recombination ◽  
Convenient Means ◽  
Recombination Processes ◽  
Stirring Time ◽  
Zno Powders ◽  
Ft Ir ◽  
Volume Defect

AbstractZnO powders with particle size in the nm to μm range have been fabricated by sonochemical method, utilizing zinc acetate and sodium hydroxide as starting materials. Carrier recombination processes in the powders have been investigated using the photoluminescence, FT-IR and surface photovoltage techniques. It has been shown that the photoluminescence spectra exhibit a number of defect-related emission bands which are typically observed in ZnO lattice and which depend on the sonication time. It has been found that the increase of the stirring time results in a faster decay of the photovoltage transients for times shorter than approximately 5 ms. From the obtained data it has been concluded that the sonication modifies the complicated trapping dynamics from volume to surface defects, whereas the fabrication method itself offers a remarkably convenient means of modifying the relative content of the surface-to-volume defect ratio in powder grains and altering the dynamics of photoexcited carriers.

Deep Level Energy Analysis of Surface and Bulk Defects Using a Noncontact Laser/Microwave Photoconductance Technique

1992 ◽  
Vol 261 ◽  
Author(s):  
A. Buczkowski ◽  
G. A. Rozgonyi ◽  
F. Shimura
Keyword(s):  
Energy Analysis ◽  
Deep Level ◽  
Energy Levels ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Level Energy ◽  
Recombination Lifetime ◽  
Recombination Processes ◽  
Bulk Energy ◽  
Recombination Velocity

ABSTRACTA noncontact technique for deep level energy analysis has been discussed based on a laser excitation/microwave reflection transient photoconductance procedure. An algorithm for separation of surface and bulk recombination effects was developed to independently determinesurface and bulk energy states. Deep energy levels associated with trapping and recombination processes have been calculated from the temperature dependence of surface recombination velocity and bulk recombination lifetime, based on state occupation statistics. Results have been compared with conventional DLTS data for silicon samples intentionally doped with metals during crystal growth.

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