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}
Pub Date : 2025-02-01DOI: 10.1016/j.omx.2024.100392
Kuat K. Kumarbekov , Askhat B. Kakimov , Zhakyp T. Karipbayev , Murat T. Kassymzhanov , Mikhail G. Brik , Chong-geng Ma , Michał Piasecki , Yana Suchikova , Meldra Kemere , Marina Konuhova
This study explores the synthesis and luminescent properties of europium-doped gallium oxide (Ga₂O₃:Eu) ceramics fabricated via electron beam-assisted synthesis (EBAS) at 1.4 MeV. The resulting Ga₂O₃:Eu ceramics exhibit a nanocrystalline structure with an average crystallite size of ∼30 nm, high crystallinity, and minimal lattice strain (<0.5 %). Luminescence analysis from 4 K to 300 K reveals both intrinsic and europium-induced emissions. While intrinsic Ga₂O₃ emission exhibits thermal quenching above 100 K, Eu³⁺-related emissions, notably the 611 nm red emission, show thermal stability, retaining ∼90 % of their intensity at 300 K. Additionally, a novel low-temperature emission peak at 1.74 eV, potentially associated with electron beam-induced defects, was detected, meriting further exploration. These findings indicate that Ga₂O₃:Eu ceramics synthesized via EBAS hold promise for optoelectronic, radiation detection, and high-temperature applications, given their rapid production and enhanced thermal stability.
{"title":"Temperature-dependent luminescence of europium-doped Ga₂O₃ ceramics","authors":"Kuat K. Kumarbekov , Askhat B. Kakimov , Zhakyp T. Karipbayev , Murat T. Kassymzhanov , Mikhail G. Brik , Chong-geng Ma , Michał Piasecki , Yana Suchikova , Meldra Kemere , Marina Konuhova","doi":"10.1016/j.omx.2024.100392","DOIUrl":"10.1016/j.omx.2024.100392","url":null,"abstract":"<div><div>This study explores the synthesis and luminescent properties of europium-doped gallium oxide (Ga₂O₃:Eu) ceramics fabricated via electron beam-assisted synthesis (EBAS) at 1.4 MeV. The resulting Ga₂O₃:Eu ceramics exhibit a nanocrystalline structure with an average crystallite size of ∼30 nm, high crystallinity, and minimal lattice strain (<0.5 %). Luminescence analysis from 4 K to 300 K reveals both intrinsic and europium-induced emissions. While intrinsic Ga₂O₃ emission exhibits thermal quenching above 100 K, Eu³⁺-related emissions, notably the 611 nm red emission, show thermal stability, retaining ∼90 % of their intensity at 300 K. Additionally, a novel low-temperature emission peak at 1.74 eV, potentially associated with electron beam-induced defects, was detected, meriting further exploration. These findings indicate that Ga₂O₃:Eu ceramics synthesized via EBAS hold promise for optoelectronic, radiation detection, and high-temperature applications, given their rapid production and enhanced thermal stability.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100392"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181688","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.2025.100401
Ibrahim Oksuz , Sabin Neupane , Yanfa Yan , Lei R. Cao
A nuclear photovoltaic battery uses scintillator to convert radiation into visible light, which is then collected by a photovoltaic (PV) cell to generate electricity. If the radiation is gamma-rays emitted from external sources, the battery may also be referred as gammavoltaic battery. In this study, a polycrystalline CdTe solar cell was optically coupled with a 2.0 cm × 2.0 cm × 1.0 cm Gadolinium Aluminum Gallium Garnet (GAGG) scintillator, and the resulting device was tested using intense gamma radiation fields from a Cs-137 (1.5 kRad/h) and a Co-60 (10 kRad/h) irradiator. Measurements with Cs-137 provided a maximum power output (Pmax) of ∼288 nW, with a short-circuit current density (Jsc) of ∼1.22 μA/cm2 and an open-circuit voltage (Voc) of ∼0.34 V. In contrast, Co-60 irradiator gave a Pmax of 1.5 μW, with a Jsc of ∼4.73 μA/cm2 and a Voc of ∼0.38 V. The CdTe was also paired with a Lutetium-Yttrium Oxyorthosilicate (LYSO) crystal and tested with the Cs-137 source. The experiment presents a scalable option to reach to higher power outputs by harvesting gamma radiation fields in many cases where high radiation field demands heavy shielding and is often regarded as unwanted waste.
{"title":"Scintillator based nuclear photovoltaic batteries for power generation at microwatts level","authors":"Ibrahim Oksuz , Sabin Neupane , Yanfa Yan , Lei R. Cao","doi":"10.1016/j.omx.2025.100401","DOIUrl":"10.1016/j.omx.2025.100401","url":null,"abstract":"<div><div>A nuclear photovoltaic battery uses scintillator to convert radiation into visible light, which is then collected by a photovoltaic (PV) cell to generate electricity. If the radiation is gamma-rays emitted from external sources, the battery may also be referred as gammavoltaic battery. In this study, a polycrystalline CdTe solar cell was optically coupled with a 2.0 cm × 2.0 cm × 1.0 cm Gadolinium Aluminum Gallium Garnet (GAGG) scintillator, and the resulting device was tested using intense gamma radiation fields from a Cs-137 (1.5 kRad/h) and a Co-60 (10 kRad/h) irradiator. Measurements with Cs-137 provided a maximum power output (P<sub>max</sub>) of ∼288 nW, with a short-circuit current density (J<sub>sc</sub>) of ∼1.22 μA/cm<sup>2</sup> and an open-circuit voltage (V<sub>oc</sub>) of ∼0.34 V. In contrast, Co-60 irradiator gave a P<sub>max</sub> of 1.5 μW, with a J<sub>sc</sub> of ∼4.73 μA/cm<sup>2</sup> and a V<sub>oc</sub> of ∼0.38 V. The CdTe was also paired with a Lutetium-Yttrium Oxyorthosilicate (LYSO) crystal and tested with the Cs-137 source. The experiment presents a scalable option to reach to higher power outputs by harvesting gamma radiation fields in many cases where high radiation field demands heavy shielding and is often regarded as unwanted waste.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100401"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182667","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.2024.100387
Dmitriy I. Shlimas , Daryn B. Borgekov , Artem L. Kozlovskiy
The aim of this study is to determine the differences in the damaged layer degradation kinetics in two-phase lithium-containing ceramics based on Li2ZrO3 and Li4SiO4 compounds in the case of irradiation with protons and helium ions, simulating the gas swelling and blistering processes, as well as the accumulation of radiolysis products in the damaged layer. During the conducted studies it was established that in the case of proton irradiation, the dominant role at fluences of 1015–1017 cm−2 is played by oxygen vacancies, the change in the concentration of which upon reaching critical values causes a decrease in the thermophysical properties, and disordering of the damaged layer. In this case, the accumulation of radiolysis products in the form of HC2 – and Zr3+ -defects in the structure of the damaged layer is observed at fluences of 5 × 1017 cm−2, while when irradiated with He2+ ions, the formation of these types of HC2 – and Zr3+ -defects is observed at a fluence of 1017 cm−2. Comparison of the concentration dependences of defects in the damaged layer on the atomic displacement value under irradiation with protons and He2+ ions revealed that the formation of oxygen vacancies under irradiation with He2+ ions is more intense than in the case of irradiation with protons, which in turn results in more pronounced processes of accumulation of radiolysis products in the case of high-dose irradiation.
{"title":"Application of EPR spectroscopy method for comparative analysis of structural damage accumulation kinetics in two-phase lithium-containing ceramics","authors":"Dmitriy I. Shlimas , Daryn B. Borgekov , Artem L. Kozlovskiy","doi":"10.1016/j.omx.2024.100387","DOIUrl":"10.1016/j.omx.2024.100387","url":null,"abstract":"<div><div>The aim of this study is to determine the differences in the damaged layer degradation kinetics in two-phase lithium-containing ceramics based on Li<sub>2</sub>ZrO<sub>3</sub> and Li<sub>4</sub>SiO<sub>4</sub> compounds in the case of irradiation with protons and helium ions, simulating the gas swelling and blistering processes, as well as the accumulation of radiolysis products in the damaged layer. During the conducted studies it was established that in the case of proton irradiation, the dominant role at fluences of 10<sup>15</sup>–10<sup>17</sup> cm<sup>−2</sup> is played by oxygen vacancies, the change in the concentration of which upon reaching critical values causes a decrease in the thermophysical properties, and disordering of the damaged layer. In this case, the accumulation of radiolysis products in the form of HC<sub>2</sub> – and Zr<sup>3+</sup> -defects in the structure of the damaged layer is observed at fluences of 5 × 10<sup>17</sup> cm<sup>−2</sup>, while when irradiated with He<sup>2+</sup> ions, the formation of these types of HC<sub>2</sub> – and Zr<sup>3+</sup> -defects is observed at a fluence of 10<sup>17</sup> cm<sup>−2</sup>. Comparison of the concentration dependences of defects in the damaged layer on the atomic displacement value under irradiation with protons and He<sup>2+</sup> ions revealed that the formation of oxygen vacancies under irradiation with He<sup>2+</sup> ions is more intense than in the case of irradiation with protons, which in turn results in more pronounced processes of accumulation of radiolysis products in the case of high-dose irradiation.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100387"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181705","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}
In this work the influence of a short-pulsed ion irradiation with a high flux (∼5.5∙1019 cm−2s−1) on structure, optical and photo-electrical properties of gallium oxide thin films have been investigated. The films were produced by the radio-frequency magnetron sputtering method. A part of deposited films was annealed in the air environment (900 °C, 2 h) for synthesis of β-Ga2O3 phase. Obtained films were subjected to the short-pulsed ion irradiation (ion energy - up to 200 keV, pulse duration - 90 ns, current density on the target - up to 15 A/cm2). The influence of the annealing and the irradiation on spectral dependences of absorption, the bandgap width and the Urbach energy have been determined. It was found that irradiation leads to amorphization of crystalline β-Ga2O3 films and a significant change in optical characteristics. In addition, we measured the magnitude of surface dark and photoconductivity of the films. Also, the field and spectral dependences of the photosensitivity of the films were researched. As a result, it was established that short-pulsed irradiation improves the photoelectric properties of amorphous gallium oxide films. The reasons of it are discussed.
{"title":"Influence of short-pulsed Ion irradiation on optical and photoelectrical properties of thin gallium oxide films","authors":"Zhanymgul Koishybayeva , Fedor Konusov , Sergey Pavlov , Dmitrii Sidelev , Artur Nassyrbayev , Dmitry Cheshev , Ruslan Gadyrov , Vladislav Tarbokov , Abdirash Akilbekov","doi":"10.1016/j.omx.2024.100394","DOIUrl":"10.1016/j.omx.2024.100394","url":null,"abstract":"<div><div>In this work the influence of a short-pulsed ion irradiation with a high flux (∼5.5∙10<sup>19</sup> cm<sup>−2</sup>s<sup>−1</sup>) on structure, optical and photo-electrical properties of gallium oxide thin films have been investigated. The films were produced by the radio-frequency magnetron sputtering method. A part of deposited films was annealed in the air environment (900 °C, 2 h) for synthesis of β-Ga<sub>2</sub>O<sub>3</sub> phase. Obtained films were subjected to the short-pulsed ion irradiation (ion energy - up to 200 keV, pulse duration - 90 ns, current density on the target - up to 15 A/cm<sup>2</sup>). The influence of the annealing and the irradiation on spectral dependences of absorption, the bandgap width and the Urbach energy have been determined. It was found that irradiation leads to amorphization of crystalline β-Ga<sub>2</sub>O<sub>3</sub> films and a significant change in optical characteristics. In addition, we measured the magnitude of surface dark and photoconductivity of the films. Also, the field and spectral dependences of the photosensitivity of the films were researched. As a result, it was established that short-pulsed irradiation improves the photoelectric properties of amorphous gallium oxide films. The reasons of it are discussed.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100394"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182668","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.2024.100382
G.A. Kaptagay , B.M. Satanova , A.U. Abuova , M. Konuhova , Zh.Ye. Zakiyeva , U. Zh Tolegen , N.O. Koilyk , F.U. Abuova
By means of DFT oxygen evolution reaction on Rh-doped BaTiO3 (001) surface has been modeled. Gibbs free energies for each step of the reaction as well as the values of overpotential have been calculated, taking into account the solvation effect. The position of Rh-induces defect energy levels have been determined. Our findings indicated a substantial reduction in overpotential for the Rhodium-modified TiO2 surface compared to the bare surface. The high overpotential on the bare BaTiO3 surface suggests low OER efficiency, making Rh doping a promising strategy for enhancement.
{"title":"Effect of rhodium doping for photocatalytic activity of barium titanate","authors":"G.A. Kaptagay , B.M. Satanova , A.U. Abuova , M. Konuhova , Zh.Ye. Zakiyeva , U. Zh Tolegen , N.O. Koilyk , F.U. Abuova","doi":"10.1016/j.omx.2024.100382","DOIUrl":"10.1016/j.omx.2024.100382","url":null,"abstract":"<div><div>By means of DFT oxygen evolution reaction on Rh-doped BaTiO<sub>3</sub> (001) surface has been modeled. Gibbs free energies for each step of the reaction as well as the values of overpotential have been calculated, taking into account the solvation effect. The position of Rh-induces defect energy levels have been determined. Our findings indicated a substantial reduction in overpotential for the Rhodium-modified TiO<sub>2</sub> surface compared to the bare surface. The high overpotential on the bare BaTiO<sub>3</sub> surface suggests low OER efficiency, making Rh doping a promising strategy for enhancement.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100382"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181689","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.2024.100395
K. Shunkeyev , А. Kenzhebayeva , A. Krasnikov , V. Nagirnyi , Sh Sagimbayeva , D. Sergeyev , А. Tilep , Zh Ubaev , A. Lushchik
The study is focused on luminescence features of bound excitons (exciton-like formations, ELFs) in KCl:Na single crystals created in the field of sodium impurity ions either directly at photoexcitation or via the recombination of electron-hole pairs. The intensity of the X-ray luminescence (XRL) bands peaked at 2.8 and 3.1 eV (emission of recombinationally formed and relaxed ELFs) increases with both, the concentration of sodium impurity ions (10 → 1000 ppm) and the detection temperature (85 → 350 K). It is worth noting that at room temperature, the light yield of these XRL bands in KCl:Na practically coincides with that for the luminescence measured in the same way in classical scintillators, CsI and CsI:Na crystals. The lifetime of the fast component of cathodoluminescence at 2.8 and 3.1 eV equals 2.4 and 1.7 ns, respectively, at 6 K and even shortens to approximately τ ≈ 0.3 ns at room temperature. At 10 K, photons of 7.6 and 6.7 eV directly form ELFs in the field of single or paired Na+ impurity ions with typical luminescence bands peaked, respectively, at 2.8 eV ( (Na+)) and 3.1 eV ( (Na+-Na+)). These photoluminescence bands undergo complete thermal quenching by 200–300 K, whereas relevant XRL bands are not quenched up to 350 K, their intensity even noticeably increases at 200 → 350 K.
研究的重点是 KCl:Na 单晶中结合激子（类激子形成，ELFs）的发光特征，这些结合激子是在钠杂质离子场中直接通过光激发或电子-空穴对重组产生的。峰值为 2.8 和 3.1 eV 的 X 射线发光（XRL）带（重组形成和弛豫 ELF 的发射）强度随着钠杂质离子浓度（10 → 1000 ppm）和检测温度（85 → 350 K）的增加而增加。值得注意的是，在室温下，KCl:Na 中这些 XRL 波段的光产率实际上与在经典闪烁体、CsI 和 CsI:Na 晶体中以同样方式测量的发光光产率相吻合。在 6 K 时，2.8 和 3.1 eV 的阴极荧光快速分量的寿命分别为 2.4 和 1.7 ns，在室温下甚至缩短至约 τ ≈ 0.3 ns。在 10 K 时，7.6 和 6.7 eV 的光子直接在单个或成对 Na+ 杂质离子场中形成 ELF，典型的发光带分别在 2.8 eV （el0 (Na+)）和 3.1 eV （el0 (Na+-Na+)）处达到峰值。这些光致发光带在 200-300 K 时会完全热淬灭，而相关的 XRL 发光带在 350 K 时不会被淬灭，其强度甚至在 200 → 350 K 时会明显增加。
{"title":"Luminescence of bound excitons created near sodium impurity ions in KCl:Na single crystals","authors":"K. Shunkeyev , А. Kenzhebayeva , A. Krasnikov , V. Nagirnyi , Sh Sagimbayeva , D. Sergeyev , А. Tilep , Zh Ubaev , A. Lushchik","doi":"10.1016/j.omx.2024.100395","DOIUrl":"10.1016/j.omx.2024.100395","url":null,"abstract":"<div><div>The study is focused on luminescence features of bound excitons (exciton-like formations, ELFs) in KCl:Na single crystals created in the field of sodium impurity ions either directly at photoexcitation or via the recombination of electron-hole pairs. The intensity of the X-ray luminescence (XRL) bands peaked at 2.8 and 3.1 eV (emission of recombinationally formed and relaxed ELFs) increases with both, the concentration of sodium impurity ions (10 → 1000 ppm) and the detection temperature (85 → 350 K). It is worth noting that at room temperature, the light yield of these XRL bands in KCl:Na practically coincides with that for the luminescence measured in the same way in classical scintillators, CsI and CsI:Na crystals. The lifetime of the fast component of cathodoluminescence at 2.8 and 3.1 eV equals 2.4 and 1.7 ns, respectively, at 6 K and even shortens to approximately <em>τ</em> ≈ 0.3 ns at room temperature. At 10 K, photons of 7.6 and 6.7 eV directly form ELFs in the field of single or paired Na<sup>+</sup> impurity ions with typical luminescence bands peaked, respectively, at 2.8 eV (<span><math><mrow><msubsup><mi>e</mi><mi>l</mi><mn>0</mn></msubsup></mrow></math></span> (Na<sup>+</sup>)) and 3.1 eV (<span><math><mrow><msubsup><mi>e</mi><mi>l</mi><mn>0</mn></msubsup></mrow></math></span> (Na<sup>+</sup>-Na<sup>+</sup>)). These photoluminescence bands undergo complete thermal quenching by 200–300 K, whereas relevant XRL bands are not quenched up to 350 K, their intensity even noticeably increases at 200 → 350 K.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100395"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182669","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.2025.100399
Zhanymgul Koishybayeva , Fedor Konusov , Sergey Pavlov , Dmitrii Sidelev , Artur Nassyrbayev , Ruslan Gadyrov , Vladislav Tarbokov , Elena Polisadova , Abdirash Akilbekov
In this work the effect of an intense pulsed ion irradiation with a high flux ∼1020 cm−2s−1 on structure, optical and photo-electrical properties of gallium oxide thin films have been investigated. The films were produced by the radio-frequency magnetron sputtering method and had amorphous structure. A part of deposited films was annealed in the air environment (900 °C, 1 h) for synthesis of β-Ga2O3 phase. Obtained films were subjected to the intense pulsed ion irradiation (ion energy - up to 200 keV, pulse duration - 100 ns, current density on the target - up to 30 A/cm2, number of pulses - 3). The influence of irradiation on optical absorption and photoluminescence spectra, field and temperature dependencies of dark and photoconductivity were investigated. The probable nature of growth defects is discussed, and a scheme of electronic transitions that determine optical properties is proposed.
{"title":"Modification of optical and photoelectrical properties of thin gallium oxide films by intense pulsed 200 keV C+ ion beams","authors":"Zhanymgul Koishybayeva , Fedor Konusov , Sergey Pavlov , Dmitrii Sidelev , Artur Nassyrbayev , Ruslan Gadyrov , Vladislav Tarbokov , Elena Polisadova , Abdirash Akilbekov","doi":"10.1016/j.omx.2025.100399","DOIUrl":"10.1016/j.omx.2025.100399","url":null,"abstract":"<div><div>In this work the effect of an intense pulsed ion irradiation with a high flux ∼10<sup>20</sup> cm<sup>−2</sup>s<sup>−1</sup> on structure, optical and photo-electrical properties of gallium oxide thin films have been investigated. The films were produced by the radio-frequency magnetron sputtering method and had amorphous structure. A part of deposited films was annealed in the air environment (900 °C, 1 h) for synthesis of β-Ga<sub>2</sub>O<sub>3</sub> phase. Obtained films were subjected to the intense pulsed ion irradiation (ion energy - up to 200 keV, pulse duration - 100 ns, current density on the target - up to 30 A/cm<sup>2</sup>, number of pulses - 3). The influence of irradiation on optical absorption and photoluminescence spectra, field and temperature dependencies of dark and photoconductivity were investigated. The probable nature of growth defects is discussed, and a scheme of electronic transitions that determine optical properties is proposed.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100399"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182673","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}
Ce3+-doped compounds are typically the preferred materials for the development of inorganic phosphors for white LEDs, displays, and scintillators. In this study, pump-probe absorption spectroscopy was performed for Gd3Ga5O12:Ce and Gd3Al1Ga4O12:Ce crystals using ultraviolet (UV) and visible (VIS) pump light, and infrared (IR) probe light. A change in the IR-absorption was observed owing to the generation of free carrier plasma via photoexcitation. Through a simple analysis, the excitation spectra of this change determined the energy at the bottom of the conduction band relative to that at the Ce3+ 4f level. The transient response of the IR-absorption change suggested different relaxation processes for excited electrons in Gd3Ga5O12:Ce and Gd3Al1Ga4O12:Ce. Analysis of the thermally stimulated luminescence (TSL) glow curve determined the trap depth of the electrons in Gd3Al1Ga4O12:Ce. Based on positron annihilation lifetime spectroscopy (PALS), the generation of electron traps was linked to the introduction of vacancy complexes or vacancy aggregates with a negative charge, namely nonstoichiometric compositions. This helps achieve high-quality Ce3+-doped multicomponent oxides.
{"title":"Relationship between Ce3+ 5d1 level, conduction-band bottom, and shallow electron trap level in Gd3Ga5O12:Ce and Gd3Al1Ga4O12:Ce crystals studied via pump-probe absorption spectroscopy","authors":"Mamoru Kitaura , Heishun Zen , Shinta Watanabe , Hirokazu Masai , Kei Kamada , Kyoung-Jin Kim , Akira Yoshikawa , Jumpei Ueda","doi":"10.1016/j.omx.2024.100398","DOIUrl":"10.1016/j.omx.2024.100398","url":null,"abstract":"<div><div>Ce<sup>3+</sup>-doped compounds are typically the preferred materials for the development of inorganic phosphors for white LEDs, displays, and scintillators. In this study, pump-probe absorption spectroscopy was performed for Gd<sub>3</sub>Ga<sub>5</sub>O<sub>12</sub>:Ce and Gd<sub>3</sub>Al<sub>1</sub>Ga<sub>4</sub>O<sub>12</sub>:Ce crystals using ultraviolet (UV) and visible (VIS) pump light, and infrared (IR) probe light. A change in the IR-absorption was observed owing to the generation of free carrier plasma via photoexcitation. Through a simple analysis, the excitation spectra of this change determined the energy at the bottom of the conduction band relative to that at the Ce<sup>3+</sup> 4f level. The transient response of the IR-absorption change suggested different relaxation processes for excited electrons in Gd<sub>3</sub>Ga<sub>5</sub>O<sub>12</sub>:Ce and Gd<sub>3</sub>Al<sub>1</sub>Ga<sub>4</sub>O<sub>12</sub>:Ce. Analysis of the thermally stimulated luminescence (TSL) glow curve determined the trap depth of the electrons in Gd<sub>3</sub>Al<sub>1</sub>Ga<sub>4</sub>O<sub>12</sub>:Ce. Based on positron annihilation lifetime spectroscopy (PALS), the generation of electron traps was linked to the introduction of vacancy complexes or vacancy aggregates with a negative charge, namely nonstoichiometric compositions. This helps achieve high-quality Ce<sup>3+</sup>-doped multicomponent oxides.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100398"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182671","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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