Pub Date : 2025-03-07DOI: 10.1016/j.omx.2025.100410
Artem L. Kozlovskiy , Dmitriy I. Shlimas , Natalya Volodina , Gulnaz ZhMoldabayeva , Mussa Kabiyev , Marina Konuhova
The paper presents the results of studies of the influence of phase formation processes with variations in annealing temperature on the processes of stabilization of the crystal structure, optical and thermal properties of Nd2Zr2O7 ceramics, which have great potential for use in optoelectronic applications due to the transitions of Nd3 ions, as well as high stability to external factors with the possibility of creating transparent ceramics. During the conducted studies it was established that the stabilization temperature of the Nd2Zr2O7 phase is 1100–1250 °C, at which the throughput is maximum, and the thermal conductivity coefficient is about 2.1–2.2 W/m × K. The assessment of phase transformations and changes in optical properties revealed that an elevation in the annealing temperature, leading to stabilization of the Nd2Zr2O7 phase, leads to a decrease in the concentration of oxygen vacancies in the structure of ceramics; however, at temperatures above 1200 °C, the observed growth in oxygen vacancies is due to the effects of substitution of Zr4+ cations by Nd3+ cations, which results in formation of additional oxygen vacancies in the structure, alongside impurity inclusions in the form of a cubic phase of Zr(Nd)O2, which is a product of phase polymorphic transformations during high-temperature annealing. Alterations in the thermophysical properties of Nd2Zr2O7 ceramics are directly dependent on phase formation processes and associated changes in the concentration of oxygen vacancies, which are the determining factor influencing the heat transfer rate.
{"title":"Study of the effect of phase formation processes on the change in optical and thermal properties of Nd2Zr2O7 ceramics with a pyrochlore structure","authors":"Artem L. Kozlovskiy , Dmitriy I. Shlimas , Natalya Volodina , Gulnaz ZhMoldabayeva , Mussa Kabiyev , Marina Konuhova","doi":"10.1016/j.omx.2025.100410","DOIUrl":"10.1016/j.omx.2025.100410","url":null,"abstract":"<div><div>The paper presents the results of studies of the influence of phase formation processes with variations in annealing temperature on the processes of stabilization of the crystal structure, optical and thermal properties of Nd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> ceramics, which have great potential for use in optoelectronic applications due to the transitions of Nd<sup>3</sup> ions, as well as high stability to external factors with the possibility of creating transparent ceramics. During the conducted studies it was established that the stabilization temperature of the Nd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> phase is 1100–1250 °C, at which the throughput is maximum, and the thermal conductivity coefficient is about 2.1–2.2 W/m × K. The assessment of phase transformations and changes in optical properties revealed that an elevation in the annealing temperature, leading to stabilization of the Nd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> phase, leads to a decrease in the concentration of oxygen vacancies in the structure of ceramics; however, at temperatures above 1200 °C, the observed growth in oxygen vacancies is due to the effects of substitution of Zr<sup>4+</sup> cations by Nd<sup>3+</sup> cations, which results in formation of additional oxygen vacancies in the structure, alongside impurity inclusions in the form of a cubic phase of Zr(Nd)O<sub>2</sub>, which is a product of phase polymorphic transformations during high-temperature annealing. Alterations in the thermophysical properties of Nd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> ceramics are directly dependent on phase formation processes and associated changes in the concentration of oxygen vacancies, which are the determining factor influencing the heat transfer rate.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"26 ","pages":"Article 100410"},"PeriodicalIF":0.0,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143593752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-07DOI: 10.1016/j.omx.2025.100409
Аleksei V. Almaev , Zhakyp T. Karipbayev , Ernar B. Zhurkin , Nikita N. Yakovlev , Olzhas I. Kukenov , Alexandr O. Korchemagin , Gulzhanat A. Akmetova-Abdik , Kuat K. Kumarbekov , Amangeldy M. Zhunusbekov , Leonid A. Mochalov , Ekaterina A. Slapovskaya , Anatoli I. Popov
Ceramic pellets of pure ZnGa2O4 and ZnGa2O4 with Er-addition are synthesized and their structural and gas-sensitive properties are investigated. The addition of Er leads to the formation of a second Er3Ga5O12 phase in the ZnGa2O4 matrix and a larger active surface which allows an 11.1-fold increase in the response of ZnGa2O4 to 104 ppm of CH4. At the maximum response temperature corresponding to 650 °C, the responses to 100 and 104 ppm of CH4 for ZnGa2O4 with Er addition were 2.91 a.u. and 20.74 a.u., respectively. ZnGa2O4 with Er addition is characterized by a wide dynamic range of CH4 concentrations, from 100 ppm to 20000 ppm, weak dependence of gas-sensitive characteristics on humidity in the relative humidity range of 30–70 %, weak changes of gas-sensitive characteristics under cyclic gas exposure. The samples also demonstrate high responses to NO2 and H2, which at a gas concentration of 100 ppm and a temperature of 650 °C are 3.37 a.u. and 4.77 a.u., respectively. A plausible mechanism of the sensing effect of ZnGa2O4 with Er addition is proposed and prospects for the development of high-temperature CH4 sensors based on the studied samples for combustion monitoring systems and determination of the ideal fuel/air mixture are discussed.
{"title":"Methane sensors based on ZnGa2O4 ceramics with addition of Er for combustion monitoring systems","authors":"Аleksei V. Almaev , Zhakyp T. Karipbayev , Ernar B. Zhurkin , Nikita N. Yakovlev , Olzhas I. Kukenov , Alexandr O. Korchemagin , Gulzhanat A. Akmetova-Abdik , Kuat K. Kumarbekov , Amangeldy M. Zhunusbekov , Leonid A. Mochalov , Ekaterina A. Slapovskaya , Anatoli I. Popov","doi":"10.1016/j.omx.2025.100409","DOIUrl":"10.1016/j.omx.2025.100409","url":null,"abstract":"<div><div>Ceramic pellets of pure ZnGa<sub>2</sub>O<sub>4</sub> and ZnGa<sub>2</sub>O<sub>4</sub> with Er-addition are synthesized and their structural and gas-sensitive properties are investigated. The addition of Er leads to the formation of a second Er<sub>3</sub>Ga<sub>5</sub>O<sub>12</sub> phase in the ZnGa<sub>2</sub>O<sub>4</sub> matrix and a larger active surface which allows an 11.1-fold increase in the response of ZnGa<sub>2</sub>O<sub>4</sub> to 10<sup>4</sup> ppm of CH<sub>4</sub>. At the maximum response temperature corresponding to 650 °C, the responses to 100 and 10<sup>4</sup> ppm of CH<sub>4</sub> for ZnGa<sub>2</sub>O<sub>4</sub> with Er addition were 2.91 a.u. and 20.74 a.u., respectively. ZnGa<sub>2</sub>O<sub>4</sub> with Er addition is characterized by a wide dynamic range of CH<sub>4</sub> concentrations, from 100 ppm to 20000 ppm, weak dependence of gas-sensitive characteristics on humidity in the relative humidity range of 30–70 %, weak changes of gas-sensitive characteristics under cyclic gas exposure. The samples also demonstrate high responses to NO<sub>2</sub> and H<sub>2</sub>, which at a gas concentration of 100 ppm and a temperature of 650 °C are 3.37 a.u. and 4.77 a.u., respectively. A plausible mechanism of the sensing effect of ZnGa<sub>2</sub>O<sub>4</sub> with Er addition is proposed and prospects for the development of high-temperature CH<sub>4</sub> sensors based on the studied samples for combustion monitoring systems and determination of the ideal fuel/air mixture are discussed.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"26 ","pages":"Article 100409"},"PeriodicalIF":0.0,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-07DOI: 10.1016/j.omx.2025.100408
I. Aulika, P. Paulsone, E. Laizane, J. Butikova, A. Vembris
In this work, we present detailed spectroscopic ellipsometry (SE) measurements across thirty indium tin oxide In2O3–SnO2 (ITO) substrates, providing insights into variations in the complex refractive index for the same commercial ITO material. This study includes an analysis of the distribution of ITO surface roughness, ITO thickness, SiO2 buffer layer thickness, and the complex refractive index of ITO including electrical resistivity and its gradient. The SE mapping, conducted over a (1.5 × 1.5) cm scan area on multiple substrates of (2.5 × 2.5) cm size, reveals uniformity in above parameters within single ITO substrate. However, substantial thickness variations in the SiO2 buffer layer along with fluctuations in the of ITO are observed across the set of substrates. Our findings underscore the importance of individually assessing each ITO substrate's optical properties prior to additional layer deposition, as this precision is essential for reliable investigations of other materials, such as organic compounds in OLEDs, in both ex-situ and in-situ studies. Additionally, this article provides comprehensive optical property data for ITO substrates consisting of soda lime float glass coated with a thin SiO2 buffer layer.
{"title":"Spatial mapping of optical constants and thickness variations in ITO films and SiO2 buffer layers","authors":"I. Aulika, P. Paulsone, E. Laizane, J. Butikova, A. Vembris","doi":"10.1016/j.omx.2025.100408","DOIUrl":"10.1016/j.omx.2025.100408","url":null,"abstract":"<div><div>In this work, we present detailed spectroscopic ellipsometry (SE) measurements across thirty indium tin oxide In<sub>2</sub>O<sub>3</sub>–SnO<sub>2</sub> (ITO) substrates, providing insights into variations in the complex refractive index <span><math><mrow><mover><mi>N</mi><mo>˜</mo></mover></mrow></math></span> for the same commercial ITO material. This study includes an analysis of the distribution of ITO surface roughness, ITO thickness, SiO<sub>2</sub> buffer layer thickness, and the complex refractive index of ITO including electrical resistivity and its gradient. The SE mapping, conducted over a (1.5 × 1.5) cm scan area on multiple substrates of (2.5 × 2.5) cm size, reveals uniformity in above parameters within single ITO substrate. However, substantial thickness variations in the SiO<sub>2</sub> buffer layer along with fluctuations in the <span><math><mrow><mover><mi>N</mi><mo>̃</mo></mover></mrow></math></span> of ITO are observed across the set of substrates. Our findings underscore the importance of individually assessing each ITO substrate's optical properties prior to additional layer deposition, as this precision is essential for reliable investigations of other materials, such as organic compounds in OLEDs, in both <em>ex-situ</em> and <em>in-situ</em> studies. Additionally, this article provides comprehensive optical property data for ITO substrates consisting of soda lime float glass coated with a thin SiO<sub>2</sub> buffer layer.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"26 ","pages":"Article 100408"},"PeriodicalIF":0.0,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lu2O3 has emerged as a highly attractive host material for gamma-ray detection, primarily due to its high density (9.4 g/cm3) and effective atomic number (68). Various dopants have been explored to enhance its scintillation properties, with notable examples including Eu3+ and Yb3+. While Eu3+ doping results in high luminosity, it suffers from a prolonged decay time in the millisecond range. On the other hand, Yb3+ produces a fast scintillation response in the nanosecond range, but at the cost of a significantly lower light yield. Both dopants present limitations for gamma-ray spectroscopy.
Recently, we developed a novel variant of Lu2O3 doped with La3+. Given the high melting point of the host material (2490 °C), ceramic consolidation techniques were employed during synthesis, leveraging the optically isotropic cubic structure of the material. This composition offers a balanced set of properties, exhibiting a light yield as high as 20,000 photons/MeV and two dominant decay time components at 530 ns and 1230 ns. Additionally, the energy resolution at 662 keV was measured to be 5.3 %, which can be attributed to the material's highly proportional response.
Optimization of La3+ concentration revealed that the best results were achieved at a doping level of around 5 %. The material demonstrated excellent timing properties, with a fast rise time, <600 ps, and a single-channel timing resolution measured at 511 keV is 307ps. This composition is highly suited for radiation detection applications where intrinsic background noise is not a concern, such as in radiography. Furthermore, its superior timing characteristics and high stopping power make it attractive for Positron Emission Tomography (PET).
{"title":"La doped Lu2O3 scintillator","authors":"Jarek Glodo, Yimin Wang, Urmila Shirwadkar, Lakshmi Soundara Pandian","doi":"10.1016/j.omx.2025.100405","DOIUrl":"10.1016/j.omx.2025.100405","url":null,"abstract":"<div><div>Lu<sub>2</sub>O<sub>3</sub> has emerged as a highly attractive host material for gamma-ray detection, primarily due to its high density (9.4 g/cm<sup>3</sup>) and effective atomic number (68). Various dopants have been explored to enhance its scintillation properties, with notable examples including Eu<sup>3+</sup> and Yb<sup>3+</sup>. While Eu<sup>3+</sup> doping results in high luminosity, it suffers from a prolonged decay time in the millisecond range. On the other hand, Yb<sup>3+</sup> produces a fast scintillation response in the nanosecond range, but at the cost of a significantly lower light yield. Both dopants present limitations for gamma-ray spectroscopy.</div><div>Recently, we developed a novel variant of Lu<sub>2</sub>O<sub>3</sub> doped with La<sup>3+</sup>. Given the high melting point of the host material (2490 °C), ceramic consolidation techniques were employed during synthesis, leveraging the optically isotropic cubic structure of the material. This composition offers a balanced set of properties, exhibiting a light yield as high as 20,000 photons/MeV and two dominant decay time components at 530 ns and 1230 ns. Additionally, the energy resolution at 662 keV was measured to be 5.3 %, which can be attributed to the material's highly proportional response.</div><div>Optimization of La<sup>3+</sup> concentration revealed that the best results were achieved at a doping level of around 5 %. The material demonstrated excellent timing properties, with a fast rise time, <600 ps, and a single-channel timing resolution measured at 511 keV is 307ps. This composition is highly suited for radiation detection applications where intrinsic background noise is not a concern, such as in radiography. Furthermore, its superior timing characteristics and high stopping power make it attractive for Positron Emission Tomography (PET).</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"26 ","pages":"Article 100405"},"PeriodicalIF":0.0,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-22DOI: 10.1016/j.omx.2025.100407
Mathis Van de Voorde , Damien Hudry , Dmitry Busko , Bryce S. Richards , Rebecca Saive
The development of near infra-red (NIR) emitting down-converters is a promising route for improving photovoltaic output through efficient light management. Quantum-cutting Yb3+-doped CsPbCl3 nanocrystals (NCs) are interesting for this application due to their high photoluminescence quantum yields (PLQY >100 %) and attractive NIR spectral properties which include high absorption cross section and minimal overlap between absorption and emission spectra. In this work, we fabricated CsPbCl3:Yb3+ NCs with the hot-injection method and studied them using structural/optical characterization methods such as x-ray diffraction, scanning transmission electron microscopy, energy-dispersive x-ray spectroscopy, fluorescence lifetime and quantum yield measurements. We found that the hot-injection method is susceptible to the formation of colloidally stable Yb-rich reaction by-products. After separating these by-products from the NCs, NIR PLQY increased by a relative 46 %. Although the PLQY values recorded in this study are 4–7 times lower than in other studies, these findings may explain some discrepancies in photoluminescence efficiency reported with this material.
{"title":"CsPbCl3:Yb3+ nanocrystals: Adverse effects of colloidally stable ytterbium-rich reaction by-products on luminescent down-conversion performance","authors":"Mathis Van de Voorde , Damien Hudry , Dmitry Busko , Bryce S. Richards , Rebecca Saive","doi":"10.1016/j.omx.2025.100407","DOIUrl":"10.1016/j.omx.2025.100407","url":null,"abstract":"<div><div>The development of near infra-red (NIR) emitting down-converters is a promising route for improving photovoltaic output through efficient light management. Quantum-cutting Yb<sup>3+</sup>-doped CsPbCl<sub>3</sub> nanocrystals (NCs) are interesting for this application due to their high photoluminescence quantum yields (PLQY >100 %) and attractive NIR spectral properties which include high absorption cross section and minimal overlap between absorption and emission spectra. In this work, we fabricated CsPbCl<sub>3</sub>:Yb<sup>3+</sup> NCs with the hot-injection method and studied them using structural/optical characterization methods such as x-ray diffraction, scanning transmission electron microscopy, energy-dispersive x-ray spectroscopy, fluorescence lifetime and quantum yield measurements. We found that the hot-injection method is susceptible to the formation of colloidally stable Yb-rich reaction by-products. After separating these by-products from the NCs, NIR PLQY increased by a relative 46 %. Although the PLQY values recorded in this study are 4–7 times lower than in other studies, these findings may explain some discrepancies in photoluminescence efficiency reported with this material.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"26 ","pages":"Article 100407"},"PeriodicalIF":0.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143507922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-20DOI: 10.1016/j.omx.2025.100406
Maxim V. Zdorovets , Artem A. Kozlovskiy , Gulnaz ZhMoldabayeva , Igor A. Ivanov , Marina Konuhova
The paper presents the results of a study of the connection between structural changes caused by irradiation with heavy Xe22+ ions in MgO ceramics, which are characteristic of the damage accumulation caused by exposure to nuclear fuel fission fragments. Interest in this type of ceramics, as one of the promising classes of dielectrics, is due to the potential for using them as materials for creating a matrix that holds fissile nuclear fuel, and in the case of consideration of these ceramics as dopants used to enhance the resistance of inert matrices to destruction caused by irradiation. The obtained assessment results of the alterations in the transmittance coefficient for irradiated ceramics contingent upon the irradiation fluence indicate the transmittance degradation of irradiated ceramics in the UV range, caused by the accumulation of structural distortions caused by irradiation, alongside a growth in the concentration of absorbing centers and oxygen vacancies. It has been established that the dominant type of defects in the damaged layer are oxygen vacancies, the accumulation of which occurs due to deformation distortions and the rupture of chemical bonds. At the same time, the observed change in the crystal structure volume is due to the formation of complex defects of the Mg + VO type, the formation of which results in deformation broadening of the crystal lattice parameters.
{"title":"Radiation-induced degradation effects of optical properties of MgO ceramics caused by heavy ion irradiation","authors":"Maxim V. Zdorovets , Artem A. Kozlovskiy , Gulnaz ZhMoldabayeva , Igor A. Ivanov , Marina Konuhova","doi":"10.1016/j.omx.2025.100406","DOIUrl":"10.1016/j.omx.2025.100406","url":null,"abstract":"<div><div>The paper presents the results of a study of the connection between structural changes caused by irradiation with heavy Xe<sup>22+</sup> ions in MgO ceramics, which are characteristic of the damage accumulation caused by exposure to nuclear fuel fission fragments. Interest in this type of ceramics, as one of the promising classes of dielectrics, is due to the potential for using them as materials for creating a matrix that holds fissile nuclear fuel, and in the case of consideration of these ceramics as dopants used to enhance the resistance of inert matrices to destruction caused by irradiation. The obtained assessment results of the alterations in the transmittance coefficient for irradiated ceramics contingent upon the irradiation fluence indicate the transmittance degradation of irradiated ceramics in the UV range, caused by the accumulation of structural distortions caused by irradiation, alongside a growth in the concentration of absorbing centers and oxygen vacancies. It has been established that the dominant type of defects in the damaged layer are oxygen vacancies, the accumulation of which occurs due to deformation distortions and the rupture of chemical bonds. At the same time, the observed change in the crystal structure volume is due to the formation of complex defects of the Mg + V<sub>O</sub> type, the formation of which results in deformation broadening of the crystal lattice parameters.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"26 ","pages":"Article 100406"},"PeriodicalIF":0.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.omx.2025.100400
Marina Romanova , Sergii Chertopalov , Yuri Dekhtyar , Ladislav Fekete , Ján Lančok , Michal Novotný , Petr Pokorný , Anatoli I. Popov , Hermanis Sorokins , Aleksandr Vilken
The charge trapping phenomenon in the SiO2 layer of Si/SiO2 substrates during the electron beam deposition of CaF2 thin films of varying thicknesses (50–277 nm) was studied. Photoelectron emission (PE) spectroscopy was employed to analyze electron trapping mechanisms induced by the deposition process. Distinct peaks corresponding to electron traps in the SiO2 layer were identified in the PE spectra of CaF2 films. The intensity of these peaks varied with the film thickness and the accumulated electron irradiation dose. The study also investigated the relaxation of the PE spectra in both vacuum and air environments. In a vacuum, the PE peaks and integrated PE intensity remained stable for at least 24 h for CaF2 films of all thicknesses. When exposed to air, the PE peaks persisted for several days in films 125 nm thick or thinner but relaxed within several hours in 277 nm films. This rapid relaxation was attributed to a relatively high irradiation dose (about 2.5 mC) obtained during the fabrication of the 277 nm film, leading to an increased concentration of ionized F centers at the SiO2–CaF2 interface and the formation of (O2–-VA) centers upon air exposure. The relaxation of the PE spectrum intensity was attributed to electron transfer from SiO2 traps to (O2–-VA) centers. Furthermore, the possibility of a 260 nm electron escape depth for CaF2 material was confirmed.
{"title":"Charge trapping in SiO2 substrate during electron beam deposition of CaF2 thin films of different thicknesses","authors":"Marina Romanova , Sergii Chertopalov , Yuri Dekhtyar , Ladislav Fekete , Ján Lančok , Michal Novotný , Petr Pokorný , Anatoli I. Popov , Hermanis Sorokins , Aleksandr Vilken","doi":"10.1016/j.omx.2025.100400","DOIUrl":"10.1016/j.omx.2025.100400","url":null,"abstract":"<div><div>The charge trapping phenomenon in the SiO<sub>2</sub> layer of Si/SiO<sub>2</sub> substrates during the electron beam deposition of CaF<sub>2</sub> thin films of varying thicknesses (50–277 nm) was studied. Photoelectron emission (PE) spectroscopy was employed to analyze electron trapping mechanisms induced by the deposition process. Distinct peaks corresponding to electron traps in the SiO<sub>2</sub> layer were identified in the PE spectra of CaF<sub>2</sub> films. The intensity of these peaks varied with the film thickness and the accumulated electron irradiation dose. The study also investigated the relaxation of the PE spectra in both vacuum and air environments. In a vacuum, the PE peaks and integrated PE intensity remained stable for at least 24 h for CaF<sub>2</sub> films of all thicknesses. When exposed to air, the PE peaks persisted for several days in films 125 nm thick or thinner but relaxed within several hours in 277 nm films. This rapid relaxation was attributed to a relatively high irradiation dose (about 2.5 mC) obtained during the fabrication of the 277 nm film, leading to an increased concentration of ionized F centers at the SiO<sub>2</sub>–CaF<sub>2</sub> interface and the formation of (O<sup>2–</sup>-V<sub>A</sub>) centers upon air exposure. The relaxation of the PE spectrum intensity was attributed to electron transfer from SiO<sub>2</sub> traps to (O<sup>2–</sup>-V<sub>A</sub>) centers. Furthermore, the possibility of a 260 nm electron escape depth for CaF<sub>2</sub> material was confirmed.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100400"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.omx.2024.100397
G. Gordillo , O.G. Torres , C.A. Celis , M. Reinoso , J I Clavijo
Toxicity and poor stability remain major barriers to large-scale production of hybrid organic-inorganic lead halide perovskite solar cells. Considering the isoelectronic nature of lead (II) and bismuth (III) ions, stable and non-toxic alternatives for developing photovoltaic devices could potentially be found. Rb3Bi2I9 perovskite films inherently suffer from unavoidable pinhole defects and poor surface morphology, which limit device performance. In this work we explored a dual-source thermal sequential evaporation approach to growth uniform and pinhole-free morphology of Rb3Bi2I9 polycrystalline thin films. The influence of post-deposition annealing in a high-pressure N2 atmosphere on the structural, optical, morphological, and electronic properties of the resulting films was studied experimentally using X-ray diffraction (XRD), optical spectrophotometry, scanning electron microscopy (SEM), and computationally via Density Functional Theory (DFT) calculations. The results revealed that post deposition annealing significantly improves both the morphology and degradation processes of Rb3Bi2I9 films, when they are exposed to environmental conditions for long periods of time.
{"title":"Evaluation of the optical, structural, morphological and electronic properties of Rb3Bi2I9 Perovskites films prepared by Sequential Evaporation","authors":"G. Gordillo , O.G. Torres , C.A. Celis , M. Reinoso , J I Clavijo","doi":"10.1016/j.omx.2024.100397","DOIUrl":"10.1016/j.omx.2024.100397","url":null,"abstract":"<div><div>Toxicity and poor stability remain major barriers to large-scale production of hybrid organic-inorganic lead halide perovskite solar cells. Considering the isoelectronic nature of lead (II) and bismuth (III) ions, stable and non-toxic alternatives for developing photovoltaic devices could potentially be found. Rb<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> perovskite films inherently suffer from unavoidable pinhole defects and poor surface morphology, which limit device performance. In this work we explored a dual-source thermal sequential evaporation approach to growth uniform and pinhole-free morphology of Rb<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> polycrystalline thin films. The influence of post-deposition annealing in a high-pressure N2 atmosphere on the structural, optical, morphological, and electronic properties of the resulting films was studied experimentally using X-ray diffraction (XRD), optical spectrophotometry, scanning electron microscopy (SEM), and computationally via Density Functional Theory (DFT) calculations. The results revealed that post deposition annealing significantly improves both the morphology and degradation processes of Rb<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> films, when they are exposed to environmental conditions for long periods of time.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100397"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.omx.2024.100388
Dana S. Yerimbetova , Marina Konuhova , Artem L. Kozlovskiy , Umitali N. Tuichiyev
The aim of this research is to study the prospects of using the proposed methods of optical UV spectroscopy and X-ray diffractometry to determine the radiation density of the daughter products of radon decay - α-particles recorded using polymer track detectors. This paper presents the results of experiments on detecting the daughter products of radon decay - α-particles in a room on various floors for a fairly long time (within 6 months), the choice of which made it possible to determine not only the concentration dependences (growth in the density of registered α-particles) over time, but also to determine the lower limit for recording changes in the optical spectra of film detectors used to register α-particles. During the experiments, good convergence of the results of structural changes determined by optical spectroscopy and X-ray diffraction methods was established. These changes are caused by the processes of interaction of α-particles with a polymer detector, characterized by deformation distortion of the molecular chains of the polymer, leading to the formation of defects that affect changes in optical and electron density. The proposed methods were used to determine the connection between the interaction processes of α-particles with the molecular structure of polymer films used as detectors. It was determined that the most significant changes are observed at densities of registered α-particles above 104 cm−2, the value of which is the threshold value for identification of radon decay products using film detectors without chemical etching.
{"title":"Study of the application prospects of film detectors for estimation of α-radiation density","authors":"Dana S. Yerimbetova , Marina Konuhova , Artem L. Kozlovskiy , Umitali N. Tuichiyev","doi":"10.1016/j.omx.2024.100388","DOIUrl":"10.1016/j.omx.2024.100388","url":null,"abstract":"<div><div>The aim of this research is to study the prospects of using the proposed methods of optical UV spectroscopy and X-ray diffractometry to determine the radiation density of the daughter products of radon decay - α-particles recorded using polymer track detectors. This paper presents the results of experiments on detecting the daughter products of radon decay - α-particles in a room on various floors for a fairly long time (within 6 months), the choice of which made it possible to determine not only the concentration dependences (growth in the density of registered α-particles) over time, but also to determine the lower limit for recording changes in the optical spectra of film detectors used to register α-particles. During the experiments, good convergence of the results of structural changes determined by optical spectroscopy and X-ray diffraction methods was established. These changes are caused by the processes of interaction of α-particles with a polymer detector, characterized by deformation distortion of the molecular chains of the polymer, leading to the formation of defects that affect changes in optical and electron density. The proposed methods were used to determine the connection between the interaction processes of α-particles with the molecular structure of polymer films used as detectors. It was determined that the most significant changes are observed at densities of registered α-particles above 10<sup>4</sup> cm<sup>−2</sup>, the value of which is the threshold value for identification of radon decay products using film detectors without chemical etching.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100388"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.omx.2024.100390
S.G. Nedilko , O. Chukova , A. Dorofieieva , S.A. Nedilko , V. Shcherbatskyi , T. Voitenko , M. Etter , H.S. Rahimi Mosafer , W. Paszkowicz , Y. Zhydachevskyy , A. Suchocki
This work aims to clarify the relationship between the optical, particularly luminescent, characteristics of the La1-x-ySmxCayVO4-δ powder nanosized compounds with their phase composition and concentration of dopants. According to the high-accuracy XRD data, the samples are a mixture of monoclinic and tetragonal crystal phases. The diffuse reflection and photoluminescence (PL) spectra were measured and analyzed including spectral distributions and intensity ratios of the PL bands, the positions and half-widths of envelopes of the groups of lines in the PL spectra of Sm3+ ions. Estimated from the diffuse reflection data the band gap values are 3.85, and 3.82, 3.75, 3.78 eV for the samples with x = 0.1, y = 0, and (x, y) = 0.05, 0.10, 0.15, respectively. The PL excitation spectra of the La1-x-ySmxCayVO4-δ nanoparticles consist of both the wide UV wavelength band (260–360 nm) caused by transition in the VO43− molecular groups and in a set of narrow lines caused by inner f-f transitions in the Sm3+ ions (spectral range 350–520 nm). The PL spectra of the La1-x-ySmxCayVO4-δ nanoparticles contain four groups of lines (I – IV) resulting from the 4G5/2 → 6H5/2, 6H7/2, 6H9/2, and 6H11/2 transitions, respectively, in the inner f shell of the Sm3+ ions. The concentration behavior of the Sm3+ ions PL characteristics is related to the evaluation of the phase composition of La1-x-ySmxCayVO4-δ samples. It was found that the changes of the Rlum = I(III)/I(I), where I(III) and I(I) are the integrated intensities of the corresponding groups of lines, can be related to the phase composition of the La1-x-ySmxCayVO4-δ compounds. Developed in this work the combined way of structural and optical data analysis may be useful in designing other multiphase phosphor systems containing Sm3+ ions.
{"title":"Evolution of phase composition and luminescent characteristics of the La1-x-ySmxCayVO4-δ nanocrystalline phosphor","authors":"S.G. Nedilko , O. Chukova , A. Dorofieieva , S.A. Nedilko , V. Shcherbatskyi , T. Voitenko , M. Etter , H.S. Rahimi Mosafer , W. Paszkowicz , Y. Zhydachevskyy , A. Suchocki","doi":"10.1016/j.omx.2024.100390","DOIUrl":"10.1016/j.omx.2024.100390","url":null,"abstract":"<div><div>This work aims to clarify the relationship between the optical, particularly luminescent, characteristics of the La<sub>1-x-y</sub>Sm<sub>x</sub>Ca<sub>y</sub>VO<sub>4-δ</sub> powder nanosized compounds with their phase composition and concentration of dopants. According to the high-accuracy XRD data, the samples are a mixture of monoclinic and tetragonal crystal phases. The diffuse reflection and photoluminescence (PL) spectra were measured and analyzed including spectral distributions and intensity ratios of the PL bands, the positions and half-widths of envelopes of the groups of lines in the PL spectra of Sm<sup>3+</sup> ions. Estimated from the diffuse reflection data the band gap values are 3.85, and 3.82, 3.75, 3.78 eV for the samples with x = 0.1, y = 0, and (x, y) = 0.05, 0.10, 0.15, respectively. The PL excitation spectra of the La<sub>1-x-y</sub>Sm<sub>x</sub>Ca<sub>y</sub>VO<sub>4-δ</sub> nanoparticles consist of both the wide UV wavelength band (260–360 nm) caused by transition in the VO<sub>4</sub><sup>3−</sup> molecular groups and in a set of narrow lines caused by inner <em>f-f</em> transitions in the Sm<sup>3+</sup> ions (spectral range 350–520 nm). The PL spectra of the La<sub>1-x-y</sub>Sm<sub>x</sub>Ca<sub>y</sub>VO<sub>4-δ</sub> nanoparticles contain four groups of lines (I – IV) resulting from the <sup>4</sup>G<sub>5/2</sub> → <sup>6</sup>H<sub>5/2</sub>, <sup>6</sup>H<sub>7/2</sub>, <sup>6</sup>H<sub>9/2</sub>, and <sup>6</sup>H<sub>11/2</sub> transitions, respectively, in the inner <em>f</em> shell of the Sm<sup>3+</sup> ions. The concentration behavior of the Sm<sup>3+</sup> ions PL characteristics is related to the evaluation of the phase composition of La<sub>1-x-y</sub>Sm<sub>x</sub>Ca<sub>y</sub>VO<sub>4-δ</sub> samples. It was found that the changes of the R<sub>lum</sub> = I<sub>(III)</sub>/I<sub>(I)</sub>, where I<sub>(III)</sub> and I<sub>(I)</sub> are the integrated intensities of the corresponding groups of lines, can be related to the phase composition of the La<sub>1-x-y</sub>Sm<sub>x</sub>Ca<sub>y</sub>VO<sub>4-δ</sub> compounds. Developed in this work the combined way of structural and optical data analysis may be useful in designing other multiphase phosphor systems containing Sm<sup>3+</sup> ions.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100390"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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