Pub Date : 2024-10-21DOI: 10.1016/j.jcrysgro.2024.127955
K. Hiraoka , R. Yamane , M. Tokuda , K. Sugiyama
The structures of Ca9Eu(PO4)7 and Ca9Er(PO4)7 phosphors were analyzed using single-crystal X-ray diffraction. Most Eu ions reside at the medium-sized M1 and M2 sites, with a small amount occupying the M5 site. In contrast, the smaller Er ions favor the smallest M5 site. This study also demonstrates the use of anomalous X-ray scattering measurements at the Er LIII and Er LIII-edges. The energy dependencies observed in the scattering factors for Ca9Eu(PO4)7 and Ca9Er(PO4)7 confirmed the preferred distribution of Eu and Er. Because this anomalous X-ray scattering method leverages the unique anomalous dispersion terms of each element, this advanced technique, coupled with a synchrotron radiation source, is suggested to be a powerful method for distinguishing near-neighbor rare-earth elements in solid-state phosphors.
利用单晶 X 射线衍射分析了 Ca9Eu(PO4)7 和 Ca9Er(PO4)7 磷光体的结构。大多数 Eu 离子位于中等大小的 M1 和 M2 位点，少量占据 M5 位点。相反，较小的 Er 离子则偏爱最小的 M5 位点。这项研究还展示了在 Er LIII 和 Er LIII 边缘使用反常 X 射线散射测量的方法。在 Ca9Eu(PO4)7 和 Ca9Er(PO4)7 的散射因子中观察到的能量依赖性证实了 Eu 和 Er 的优先分布。由于这种反常 X 射线散射方法利用了每种元素独特的反常色散项，因此建议将这种先进的技术与同步辐射源相结合，使其成为区分固态荧光粉中近邻稀土元素的有力方法。
{"title":"Distribution of Eu and Er in Ca9RE(PO4)7 phosphors analyzed by anomalous X-ray scattering","authors":"K. Hiraoka , R. Yamane , M. Tokuda , K. Sugiyama","doi":"10.1016/j.jcrysgro.2024.127955","DOIUrl":"10.1016/j.jcrysgro.2024.127955","url":null,"abstract":"<div><div>The structures of Ca<sub>9</sub>Eu(PO<sub>4</sub>)<sub>7</sub> and Ca<sub>9</sub>Er(PO<sub>4</sub>)<sub>7</sub> phosphors were analyzed using single-crystal X-ray diffraction. Most Eu ions reside at the medium-sized M1 and M2 sites, with a small amount occupying the M5 site. In contrast, the smaller Er ions favor the smallest M5 site. This study also demonstrates the use of anomalous X-ray scattering measurements at the Er <em>L</em><sub>III</sub> and Er <em>L</em><sub>III</sub>-edges. The energy dependencies observed in the scattering factors for Ca<sub>9</sub>Eu(PO<sub>4</sub>)<sub>7</sub> and Ca<sub>9</sub>Er(PO<sub>4</sub>)<sub>7</sub> confirmed the preferred distribution of Eu and Er. Because this anomalous X-ray scattering method leverages the unique anomalous dispersion terms of each element, this advanced technique, coupled with a synchrotron radiation source, is suggested to be a powerful method for distinguishing near-neighbor rare-earth elements in solid-state phosphors.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127955"},"PeriodicalIF":1.7,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.jcrysgro.2024.127952
Kangpyo Lee , Suhyun Park , Kyunghwan Jung , In Yong Moon , Jeong Ho Ryu , Kang Min Kim
Triboelectric nanogenerators (TENGs) that operate in the contact-separation mode are widely utilized for energy harvesting owing to their simple structure, excellent durability, and high energy-conversion efficiency. This study investigated the enhanced performance of TENGs using polydimethylsiloxane (PDMS) incorporating barium titanate (BTO) and multiwalled carbon nanotubes (MWCNTs). The negative triboelectric layer, comprising PDMS with BTO and MWCNTs, and aluminum foil as both the positive triboelectric layer and electrode, were optimized to improve the TENG performance. The optimal composition of PDMS incorporating 0.01 wt% MWCNTs and 10 wt% BTO yielded output voltage and current of 394.75 V and 28.24 µA, respectively. Further enhancement was realized via the application of radio frequency plasma treatment, which increased the surface roughness and fluorine incorporation. Consequently, the output voltage and current improved to 421.06 V and 32.33 µA, respectively, with a peak power density of 4.76 W/m2 at 10 MΩ. The optimized TENG maintained consistent performance over 2000 cycles and successfully illuminated commercial LEDs, thereby demonstrating its potential for practical energy-harvesting applications.
以接触分离模式工作的三电纳米发电机（TENGs）因其结构简单、耐用性好和能量转换效率高而被广泛用于能量收集。本研究调查了使用聚二甲基硅氧烷（PDMS）结合钛酸钡（BTO）和多壁碳纳米管（MWCNTs）增强 TENG 性能的情况。为了提高 TENG 的性能，对由含有 BTO 和 MWCNTs 的 PDMS 组成的负三电层以及作为正三电层和电极的铝箔进行了优化。含有 0.01 wt% MWCNTs 和 10 wt% BTO 的 PDMS 的最佳成分产生的输出电压和电流分别为 394.75 V 和 28.24 µA。通过应用射频等离子处理，增加了表面粗糙度和氟的掺入量，从而实现了进一步的增强。因此，输出电压和电流分别提高到 421.06 V 和 32.33 µA，在 10 MΩ 时的峰值功率密度为 4.76 W/m2。经过优化的 TENG 在 2000 次循环中保持了稳定的性能，并成功点亮了商用 LED，从而证明了其在实际能量收集应用中的潜力。
{"title":"Enhanced performance of polydimethylsiloxane-based triboelectric nanogenerator using BaTiO3/MWCNTs","authors":"Kangpyo Lee , Suhyun Park , Kyunghwan Jung , In Yong Moon , Jeong Ho Ryu , Kang Min Kim","doi":"10.1016/j.jcrysgro.2024.127952","DOIUrl":"10.1016/j.jcrysgro.2024.127952","url":null,"abstract":"<div><div>Triboelectric nanogenerators (TENGs) that operate in the contact-separation mode are widely utilized for energy harvesting owing to their simple structure, excellent durability, and high energy-conversion efficiency. This study investigated the enhanced performance of TENGs using polydimethylsiloxane (PDMS) incorporating barium titanate (BTO) and multiwalled carbon nanotubes (MWCNTs). The negative triboelectric layer, comprising PDMS with BTO and MWCNTs, and aluminum foil as both the positive triboelectric layer and electrode, were optimized to improve the TENG performance. The optimal composition of PDMS incorporating 0.01 wt% MWCNTs and 10 wt% BTO yielded output voltage and current of 394.75 V and 28.24 µA, respectively. Further enhancement was realized via the application of radio frequency plasma treatment, which increased the surface roughness and fluorine incorporation. Consequently, the output voltage and current improved to 421.06 V and 32.33 µA, respectively, with a peak power density of 4.76 W/m<sup>2</sup> at 10 MΩ. The optimized TENG maintained consistent performance over 2000 cycles and successfully illuminated commercial LEDs, thereby demonstrating its potential for practical energy-harvesting applications.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127952"},"PeriodicalIF":1.7,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-20DOI: 10.1016/j.jcrysgro.2024.127958
Haiyan Wang , Zeqi Lin , Binhao Qin , Yupeng Zhang
GaN epitaxial films were grown on Si substrates by ex situ two-step method combining the technologies of pulsed laser deposition (PLD) and metal organic chemical vapor deposition (MOCVD). The N/Al ratio of high-temperature AlN (HT-AlN) buffer layer was optimized, and its influence on the HT-AlN growth mode as well as the quality of GaN epitaxial films was investigated. When the N/Al ratio was 500, the two-dimensional growth of HT-AlN was greatly enhanced, and it obtained a coalesced and smooth surface with the minimum RMS surface roughness as 1.63 nm. The as-grown GaN epitaxial film had the best crystalline quality with the minimum full-width at half maximums of GaN(0002) and GaN(10 2) as 0.14° and 0.22°, respectively. Owing to the high energy of PLD, the ex situ low-temperature AlN template had an abrupt Si/AlN interface and flat surface, which was of significance to improve the quality of HT-AlN buffer and GaN film.
{"title":"Enhancing two-dimensional growth of high-temperature AlN buffer to improve the quality of GaN on Si grown by ex situ two-step method","authors":"Haiyan Wang , Zeqi Lin , Binhao Qin , Yupeng Zhang","doi":"10.1016/j.jcrysgro.2024.127958","DOIUrl":"10.1016/j.jcrysgro.2024.127958","url":null,"abstract":"<div><div>GaN epitaxial films were grown on Si substrates by <em>ex situ</em> two-step method combining the technologies of pulsed laser deposition (PLD) and metal organic chemical vapor deposition (MOCVD). The N/Al ratio of high-temperature AlN (HT-AlN) buffer layer was optimized, and its influence on the HT-AlN growth mode as well as the quality of GaN epitaxial films was investigated. When the N/Al ratio was 500, the two-dimensional growth of HT-AlN was greatly enhanced, and it obtained a coalesced and smooth surface with the minimum RMS surface roughness as 1.63 nm. The as-grown GaN epitaxial film had the best crystalline quality with the minimum full-width at half maximums of GaN(0002) and GaN(10 <span><math><mrow><mover><mrow><mn>1</mn></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math></span> 2) as 0.14° and 0.22°, respectively. Owing to the high energy of PLD, the <em>ex situ</em> low-temperature AlN template had an abrupt Si/AlN interface and flat surface, which was of significance to improve the quality of HT-AlN buffer and GaN film.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127958"},"PeriodicalIF":1.7,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-20DOI: 10.1016/j.jcrysgro.2024.127943
Y. Kodama , T. Kawamata , S. Imashuku , K. Sugiyama , T. Mikouchi
The fine structure of red beryl from Utah, USA was analyzed using anomalous X-ray scattering measurements at the Fe K-absorption edge. The resultant Fe distribution map indicated the presence of Fe at the octahedral site. Ordinary single-crystal X-ray diffraction indicated that alkali cations were located in the interstitial area produced by the six-membered ring of SiO4, as well as partial substitution at the parent octahedral Al site by cations such as those of Fe, Mn, and Mg. X-ray near-edge absorption structural analysis for Mn and Fe indicated that they existed predominantly in the trivalent state as Mn3+ and Fe3+, respectively. Based on the results obtained from electron probe microanalysis and laser-induced breakdown spectroscopy, the structural formula of red beryl from Utah, USA was concluded to be (Na0.006K0.019Rb0.009Cs0.009)Be3 (Al1.797Fe0.140Mn0.036Mg0.015Zn0.011)Si6O18.
通过在铁的 K-吸收边缘进行反常 X 射线散射测量，分析了美国犹他州红色绿柱石的精细结构。由此得出的铁分布图表明，八面体部位存在铁。普通单晶 X 射线衍射表明，碱阳离子位于 SiO4 的六元环产生的间隙区域，以及母八面体 Al 位点被 Fe、Mn 和 Mg 等阳离子部分取代。对 Mn 和 Fe 的 X 射线近边吸收结构分析表明，它们主要以三价状态存在，分别为 Mn3+ 和 Fe3+。根据电子探针显微分析和激光诱导击穿光谱分析的结果，得出美国犹他州红色绿柱石的结构式为(Na0.006K0.019Rb0.009Cs0.009)Be3 (Al1.797Fe0.140Mn0.036Mg0.015Zn0.011)Si6O18。
{"title":"Fine structural analysis of red beryl from Utah, USA using anomalous X-ray scattering","authors":"Y. Kodama , T. Kawamata , S. Imashuku , K. Sugiyama , T. Mikouchi","doi":"10.1016/j.jcrysgro.2024.127943","DOIUrl":"10.1016/j.jcrysgro.2024.127943","url":null,"abstract":"<div><div>The fine structure of red beryl from Utah, USA was analyzed using anomalous X-ray scattering measurements at the Fe <em>K</em>-absorption edge. The resultant Fe distribution map indicated the presence of Fe at the octahedral site. Ordinary single-crystal X-ray diffraction indicated that alkali cations were located in the interstitial area produced by the six-membered ring of SiO<sub>4,</sub> as well as partial substitution at the parent octahedral Al site by cations such as those of Fe, Mn, and Mg. X-ray near-edge absorption structural analysis for Mn and Fe indicated that they existed predominantly in the trivalent state as Mn<sup>3+</sup> and Fe<sup>3+</sup>, respectively. Based on the results obtained from electron probe microanalysis and laser-induced breakdown spectroscopy, the structural formula of red beryl from Utah, USA was concluded to be (Na<sub>0.006</sub>K<sub>0.019</sub>Rb<sub>0.009</sub>Cs<sub>0.009</sub>)Be<sub>3</sub> (Al<sub>1.797</sub>Fe<sub>0.140</sub>Mn<sub>0.036</sub>Mg<sub>0.015</sub>Zn<sub>0.011</sub>)Si<sub>6</sub>O<sub>18</sub>.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127943"},"PeriodicalIF":1.7,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Copper (Cu) and other metal single crystals are useful as substrates for the deposition of atomic layer materials for many electronic applications, but the growth of large-sized single crystals is difficult to achieve. Characteristics of the metal material, namely seed elongation and intense cooling radiation at high temperatures during crystal growth, are the main challenges encountered when growing ingots with large diameters. These problems can be resolved by optimizing the crystal growth parameters. By adjusting the shoulder formation angle of the ingot shape to approximately 20° to 40°, we are able to grow a large (1-inch diameter, 30 mm length) single crystal of metal Cu using the Czochralski (CZ) method. However, the generation of suspended solids and film impurities such as reactants and precipitates and their nucleation, growth, and solidification, limited the further increase in size of the Cu crystal. Using the cone-shape die CZ (CD-CZ) method solves this problem and a 2-inch diameter Cu single crystal is successfully grown. This is the world’s largest single crystal metal grown using this method and it paves the way for the growth of other metal crystals.
{"title":"Growth of copper single crystal using cone die Czochralski method","authors":"Kazuya Takahashi , Tsuyoshi Kumagai , Marilou Cadatal-Raduban , Nobuhiko Sarukura , Toru Kawamata , Kazumasa Sugiyama , Tsuguo Fukuda","doi":"10.1016/j.jcrysgro.2024.127957","DOIUrl":"10.1016/j.jcrysgro.2024.127957","url":null,"abstract":"<div><div>Copper (Cu) and other metal single crystals are useful as substrates for the deposition of atomic layer materials for many electronic applications, but the growth of large-sized single crystals is difficult to achieve. Characteristics of the metal material, namely seed elongation and intense cooling radiation at high temperatures during crystal growth, are the main challenges encountered when growing ingots with large diameters. These problems can be resolved by optimizing the crystal growth parameters. By adjusting the shoulder formation angle of the ingot shape to approximately 20° to 40°, we are able to grow a large (1-inch diameter, 30 mm length) single crystal of metal Cu using the Czochralski (CZ) method. However, the generation of suspended solids and film impurities such as reactants and precipitates and their nucleation, growth, and solidification, limited the further increase in size of the Cu crystal. Using the cone-shape die CZ (CD-CZ) method solves this problem and a 2-inch diameter Cu single crystal is successfully grown. This is the world’s largest single crystal metal grown using this method and it paves the way for the growth of other metal crystals.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127957"},"PeriodicalIF":1.7,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.jcrysgro.2024.127953
Kai Li, Jun Zhang, Peicheng Mo, Jiarong Chen, Xiaoyi Pan, Chao Chen
The limitations on the size of single-crystal diamond applications still need to be addressed for practical use. This study systematically investigates the impact of variations in seed crystal thickness and pre-growth treatments on step bonding, defect formation, and stress distribution in the mosaic growth of single-crystal diamond films. The findings suggest that variations in seed crystal thickness within 50 μm result in a smooth mosaic junction and high crystal quality, while a 100 μm variation results in noticeable defects and stress concentrations, hindering adequate bonding. Pre-growth treatment improves crystal quality by reducing polycrystalline formations and stress concentrations. Optical microscopy and Raman mapping confirm that pre-growth treated mosaic regions exhibit smooth steps and seamless bonding, with FWHM values between 3 and 5 cm−1, consistent with the quality of non-mosaic growth regions.
{"title":"Optimizing single crystal diamond mosaic growth: A study on seed thickness variation and pre-growth treatment","authors":"Kai Li, Jun Zhang, Peicheng Mo, Jiarong Chen, Xiaoyi Pan, Chao Chen","doi":"10.1016/j.jcrysgro.2024.127953","DOIUrl":"10.1016/j.jcrysgro.2024.127953","url":null,"abstract":"<div><div>The limitations on the size of single-crystal diamond applications still need to be addressed for practical use. This study systematically investigates the impact of variations in seed crystal thickness and pre-growth treatments on step bonding, defect formation, and stress distribution in the mosaic growth of single-crystal diamond films. The findings suggest that variations in seed crystal thickness within 50 μm result in a smooth mosaic junction and high crystal quality, while a 100 μm variation results in noticeable defects and stress concentrations, hindering adequate bonding. Pre-growth treatment improves crystal quality by reducing polycrystalline formations and stress concentrations. Optical microscopy and Raman mapping confirm that pre-growth treated mosaic regions exhibit smooth steps and seamless bonding, with FWHM values between 3 and 5 cm<sup>−1</sup>, consistent with the quality of non-mosaic growth regions.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127953"},"PeriodicalIF":1.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.jcrysgro.2024.127954
Rogeria Nunes Costa , Nathan Kevin Carvalho , Julian Ticona Chambi , Marcelo H.C. Chaves , Helvécio Vinícius Antunes Rocha , Ana Maria do Espirito Santo , Silvia Lucia Cuffini
Solid-state modifications can improve drug performance. Studies have shown that multicomponent crystals, such as cocrystals and eutectic compositions, have successfully improved the performance of certain drugs, including their solubility. Nevirapine (NEV) is an antiretroviral drug with low aqueous solubility, impacting its bioavailability. This work aimed to study different nevirapine/co-former solid eutectic systems, define their phase diagrams and evaluate their dissolution properties. Caffeine (CAF), Theobromine (TEOB), and Theophylline (THEO) were chosen as co-formers due to their functional groups that can interact with NEV. Aiming to determine both temperature and eutectic composition, phase and Tamman diagrams were obtained using the differential scanning calorimetry (DSC) analysis of the mixtures indifferent NEV-co-former compositions (%w/w). Powder X-ray diffraction (PXRD) and DSC were used to characterize the eutectic materials. To assess the influence of eutectic systems on dissolution properties, we determined the powder dissolution profiles and intrinsic dissolution rates of anhydrous NEV and eutectic systems NEV-CAF and NEV-THEO using different dissolution media (pH 1.2 and pH 6.8). The eutectic compositions were calculated through the phase diagrams, interpolating the curves obtained by linear regression. Thus, the eutectic composition of the NEV-CAF system was determined to be 36.55 % NEV and eutectic temperature at 201.1 °C, while in the NEV-THEO system, the eutectic was obtained in a composition of 71.04 % NEV and eutectic temperature at 217.8 °C. Tamman diagrams were generated using the enthalpy values obtained from the DSC curves, and eutectic compositions were calculated using linear regression. The analysis revealed a eutectic composition of 36.51 % of NEV for the NEV-CAF system, and a eutectic composition of 70.94 % of NEV for the NEV-THEO system. It was not possible to determine the eutectic mass fraction of NEV-TEOB. A comparison of dissolution profiles and intrinsic dissolution rates in different dissolution media showed a significant improvement in the NEV dissolution rate in both eutectic systems. In an acidic medium, NEV dissolved 16 times faster in the NEV-CAF sample and 4 times faster in the NEV-THEO sample compared to pure anhydrous NEV. In a neutral medium, the dissolution profile of NEV was even more favorable in the same eutectic systems, showing that the increase in dissolution is relevant in a wide range of pH. In addition, the intrinsic dissolution rate in the two eutectic systems was higher than that of anhydrous NEV in all employed dissolution mediums. These eutectic systems improve the dissolution rate compared to pure NEV, offering the potential for enhancing the dissolution of poorly water-soluble drugs in the future.
{"title":"Eutectic mixtures of nevirapine: Phase diagrams, solid-state characterization, and dissolution studies","authors":"Rogeria Nunes Costa , Nathan Kevin Carvalho , Julian Ticona Chambi , Marcelo H.C. Chaves , Helvécio Vinícius Antunes Rocha , Ana Maria do Espirito Santo , Silvia Lucia Cuffini","doi":"10.1016/j.jcrysgro.2024.127954","DOIUrl":"10.1016/j.jcrysgro.2024.127954","url":null,"abstract":"<div><div>Solid-state modifications can improve drug performance. Studies have shown that multicomponent crystals, such as cocrystals and eutectic compositions, have successfully improved the performance of certain drugs, including their solubility. Nevirapine (NEV) is an antiretroviral drug with low aqueous solubility, impacting its bioavailability. This work aimed to study different nevirapine/co-former solid eutectic systems, define their phase diagrams and evaluate their dissolution properties. Caffeine (CAF), Theobromine (TEOB), and Theophylline (THEO) were chosen as co-formers due to their functional groups that can interact with NEV. Aiming to determine both temperature and eutectic composition, phase and Tamman diagrams were obtained using the differential scanning calorimetry (DSC) analysis of the mixtures indifferent NEV-co-former compositions (%w/w). Powder X-ray diffraction (PXRD) and DSC were used to characterize the eutectic materials. To assess the influence of eutectic systems on dissolution properties, we determined the powder dissolution profiles and intrinsic dissolution rates of anhydrous NEV and eutectic systems NEV-CAF and NEV-THEO using different dissolution media (pH 1.2 and pH 6.8). The eutectic compositions were calculated through the phase diagrams, interpolating the curves obtained by linear regression. Thus, the eutectic composition of the NEV-CAF system was determined to be 36.55 % NEV and eutectic temperature at 201.1 °C, while in the NEV-THEO system, the eutectic was obtained in a composition of 71.04 % NEV and eutectic temperature at 217.8 °C. Tamman diagrams were generated using the enthalpy values obtained from the DSC curves, and eutectic compositions were calculated using linear regression. The analysis revealed a eutectic composition of 36.51 % of NEV for the NEV-CAF system, and a eutectic composition of 70.94 % of NEV for the NEV-THEO system. It was not possible to determine the eutectic mass fraction of NEV-TEOB. A comparison of dissolution profiles and intrinsic dissolution rates in different dissolution media showed a significant improvement in the NEV dissolution rate in both eutectic systems. In an acidic medium, NEV dissolved 16 times faster in the NEV-CAF sample and 4 times faster in the NEV-THEO sample compared to pure anhydrous NEV. In a neutral medium, the dissolution profile of NEV was even more favorable in the same eutectic systems, showing that the increase in dissolution is relevant in a wide range of pH. In addition, the intrinsic dissolution rate in the two eutectic systems was higher than that of anhydrous NEV in all employed dissolution mediums. These eutectic systems improve the dissolution rate compared to pure NEV, offering the potential for enhancing the dissolution of poorly water-soluble drugs in the future.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127954"},"PeriodicalIF":1.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fluoride crystals with extremely wide band gaps are ideal optical materials in the UV wavelength range. Large 4-inch diameter calcium strontium fluoride (Ca0.582Sr0.418F2) single crystal was grown using the Czochralski method with a Cone-shape Die (CD-CZ). The refractive index and relative transmittance of the crystal was evaluated by cutting it into a triangular prism and polished. The direct measurement of the refractive index and relative transmittance was done by using a spectrograph to image the refraction of light as it passes through a dual prism set-up consisting of a SQ prism as reference and either CaF2 or Ca0.582Sr0.418F2 as the material under evaluation. Characterization results showed that Ca0.582Sr0.418F2 has excellent refractive index dispersion and transmittance in the UV region, confirming the applicability of the dual prism with spectrograph setup to measurements of the refractive index and relative transmittance in the UV region.
{"title":"Ultraviolet optical properties of CaSrF2 crystal grown by the cone die Czochralski method","authors":"Yugo Akabe , Kotaro Enomoto , Keito Shinohara , Marilou Raduban , Toshihiko Shimizu , Nobuhiko Sarukura , Rui Okumura , Ryosuke Kodama , Kazuya Takahashi , Toru Kawamata , Kazumasa Sugiyama , Tsuguo Fukuda","doi":"10.1016/j.jcrysgro.2024.127949","DOIUrl":"10.1016/j.jcrysgro.2024.127949","url":null,"abstract":"<div><div>Fluoride crystals with extremely wide band gaps are ideal optical materials in the UV wavelength range. Large 4-inch diameter calcium strontium fluoride (Ca<sub>0.582</sub>Sr<sub>0.418</sub>F<sub>2</sub>) single crystal was grown using the Czochralski method with a Cone-shape Die (CD-CZ). The refractive index and relative transmittance of the crystal was evaluated by cutting it into a triangular prism and polished. The direct measurement of the refractive index and relative transmittance was done by using a spectrograph to image the refraction of light as it passes through a dual prism set-up consisting of a SQ prism as reference and either CaF<sub>2</sub> or Ca<sub>0.582</sub>Sr<sub>0.418</sub>F<sub>2</sub> as the material under evaluation. Characterization results showed that Ca<sub>0.582</sub>Sr<sub>0.418</sub>F<sub>2</sub> has excellent refractive index dispersion and transmittance in the UV region, confirming the applicability of the dual prism with spectrograph setup to measurements of the refractive index and relative transmittance in the UV region.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127949"},"PeriodicalIF":1.7,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
InP is a III-V compound semiconductor with a zinc-blende crystal structure, widely used in optical communications, high-frequency millimeter-wave devices, optoelectronic integrated circuits, and solar cells. During the growth of VGF-InP single crystals, defects such as twinning, dislocations, and polycrystals are prone to occur. Experimental research on the cooling rate, an important control condition during the growth process, was conducted. By analyzing a large amount of discrete cooling data from the premium InP production and using spherical fitting algorithms for numerical analysis, the optimal cooling curve was obtained. Forward and reverse experimental verification results show that by adjusting the cooling rate at each growth stage, the recurrence of twinning and dislocations was successfully improved. Increasing the cooling rate during the shouldering process helps suppress intrinsic twinning but tends to increase dislocation density during the equal diameter stage process, leading to dislocation proliferation. Therefore, while increasing the cooling rate during shouldering, it is necessary to appropriately reduce the cooling rate during the equal diameter stage process to effectively suppress dislocation proliferation. By precisely controlling the temperature gradient and cooling rate inside the furnace, the thermal field conditions during the crystal growth process can be optimized, significantly improving the quality of InP single crystals.
{"title":"The impact of cooling rate on the structure and properties of VGF-InP single crystals","authors":"Xuefeng Zhu , Hua Wei , Guoyong Huang , Weiquan Deng","doi":"10.1016/j.jcrysgro.2024.127946","DOIUrl":"10.1016/j.jcrysgro.2024.127946","url":null,"abstract":"<div><div>InP is a III-V compound semiconductor with a zinc-blende crystal structure, widely used in optical communications, high-frequency millimeter-wave devices, optoelectronic integrated circuits, and solar cells. During the growth of VGF-InP single crystals, defects such as twinning, dislocations, and polycrystals are prone to occur. Experimental research on the cooling rate, an important control condition during the growth process, was conducted. By analyzing a large amount of discrete cooling data from the premium InP production and using spherical fitting algorithms for numerical analysis, the optimal cooling curve was obtained. Forward and reverse experimental verification results show that by adjusting the cooling rate at each growth stage, the recurrence of twinning and dislocations was successfully improved. Increasing the cooling rate during the shouldering process helps suppress intrinsic twinning but tends to increase dislocation density during the equal diameter stage process, leading to dislocation proliferation. Therefore, while increasing the cooling rate during shouldering, it is necessary to appropriately reduce the cooling rate during the equal diameter stage process to effectively suppress dislocation proliferation. By precisely controlling the temperature gradient and cooling rate inside the furnace, the thermal field conditions during the crystal growth process can be optimized, significantly improving the quality of InP single crystals.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127946"},"PeriodicalIF":1.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.jcrysgro.2024.127936
Qian Zhao , Zheng-Li Miao
Aiming at detecting and locating bubbles in transparent layer of quartz crucible during the growth of monocrystalline silicon, an improved YOLOv5s model algorithm is proposed in this paper to achieve efficient and accurate crucible bubble detection. Optimize the anchor box through the K-means algorithm to adapt to the bubble dataset before and after the use of the crucible. Utilize the FasterNet backbone network to extract contextual information, enhancing target detection effectiveness. Additionally, the ECA attention mechanism is added to enhance information exchange and improve the accuracy of small target detection. Experimental results show that the improved algorithm performs significantly in bubble detection. For bubble detection before and after use, mAP increased by 2.1 % and 3.29 %, respectively. As usage time increases, the size, shape, and distribution of bubbles in the transparent layer of the quartz crucible change significantly, directly affecting the crucible’s effectiveness. Regular monitoring and evaluation of crucible bubble changes are crucial for maintaining stability and safety in the production process. Further research could explore how these findings can optimize crucible design and usage, improving performance and longevity.
{"title":"Visual detection of thermal microvariation characteristics of transparent layer of quartz crucible","authors":"Qian Zhao , Zheng-Li Miao","doi":"10.1016/j.jcrysgro.2024.127936","DOIUrl":"10.1016/j.jcrysgro.2024.127936","url":null,"abstract":"<div><div>Aiming at detecting and locating bubbles in transparent layer of quartz crucible during the growth of monocrystalline silicon, an improved YOLOv5s model algorithm is proposed in this paper to achieve efficient and accurate crucible bubble detection. Optimize the anchor box through the K-means algorithm to adapt to the bubble dataset before and after the use of the crucible. Utilize the FasterNet backbone network to extract contextual information, enhancing target detection effectiveness. Additionally, the ECA attention mechanism is added to enhance information exchange and improve the accuracy of small target detection. Experimental results show that the improved algorithm performs significantly in bubble detection. For bubble detection before and after use, mAP increased by 2.1 % and 3.29 %, respectively. As usage time increases, the size, shape, and distribution of bubbles in the transparent layer of the quartz crucible change significantly, directly affecting the crucible’s effectiveness. Regular monitoring and evaluation of crucible bubble changes are crucial for maintaining stability and safety in the production process. Further research could explore how these findings can optimize crucible design and usage, improving performance and longevity.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127936"},"PeriodicalIF":1.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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