Pub Date : 2024-10-06DOI: 10.1016/j.jcrysgro.2024.127914
Wenkai Wu , Yao Wang , Qian Cheng , Jiale Li , Wenji Li , Qian Feng , Yachao Zhang , Jincheng Zhang , Yue Hao
In this work, the Metal-organic Chemical Vapor Deposition (MOCVD) technology was used to successfully grow Si-doped β-Ga2O3 films on C-plane sapphire substrates. The effects of Si flow rate on the surface morphology, crystal composition, electrical and optical properties of the films were characterized and analyzed. The experimental results show that the full width at half maximum (FWHM) and root mean square (RMS) of the films are improved with the decrease of Si flow rate. More importantly, only the sample with the lowest Si flow rate showed conductive ability, and its carrier concentration and mobility were 4.20 cm2/V·s and 3.33 × 1016 cm−3, respectively. In addition, we also made photodetectors corresponding to the thin films. The test results showed that the external quantum efficiency (EQE) and responsiveness (R) of the detectors improved with the decrease of Si flow rate.
{"title":"Influence of Si flow rate on the performance of MOCVD-deposited Si-doped Ga2O3 films and the applications in ultraviolet photodetectors","authors":"Wenkai Wu , Yao Wang , Qian Cheng , Jiale Li , Wenji Li , Qian Feng , Yachao Zhang , Jincheng Zhang , Yue Hao","doi":"10.1016/j.jcrysgro.2024.127914","DOIUrl":"10.1016/j.jcrysgro.2024.127914","url":null,"abstract":"<div><div>In this work, the Metal-organic Chemical Vapor Deposition (MOCVD) technology was used to successfully grow Si-doped β-Ga<sub>2</sub>O<sub>3</sub> films on C-plane sapphire substrates. The effects of Si flow rate on the surface morphology, crystal composition, electrical and optical properties of the films were characterized and analyzed. The experimental results show that the full width at half maximum (FWHM) and root mean square (RMS) of the films are improved with the decrease of Si flow rate. More importantly, only the sample with the lowest Si flow rate showed conductive ability, and its carrier concentration and mobility were 4.20 cm<sup>2</sup>/V·s and 3.33 × 10<sup>16</sup> cm<sup>−3</sup>, respectively. In addition, we also made photodetectors corresponding to the thin films. The test results showed that the external quantum efficiency (EQE) and responsiveness (R) of the detectors improved with the decrease of Si flow rate.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"648 ","pages":"Article 127914"},"PeriodicalIF":1.7,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419160","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 : 2024-10-05DOI: 10.1016/j.jcrysgro.2024.127912
Thomas E. Gore
Single crystals of crowningshieldite (α-NiS) were synthesized in three runs via chemical-vapour transport (CVT) over a 20 cm horizontal gradient of 700 → 600 °C (No. 1) and 800 → 700 °C (No. 2 & 3) in evacuated fused silica capsules using natural millerite from Coleman mine in Sudbury, Ontario, Canada with the composition (Ni0.976Fe0.013Co0.003)Σ0.992S and I2 as a transport reagent. Products were characterized via PXRD and SEM methods. Resultant crystals are euhedral, 10 to 400 μm in diameter, and occur as three distinct populations: 1) platy crystals exhibiting dominant pinacoid {} and minor dipyramid {}; 2) equant crystals with equal development of both the pinacoid {} and dipyramid {}; and 3) blocky crystals showing only the dipyramid {}. The largest crystals were produced at higher temperatures, but experiments lasting longer than 12 days did not result in significant additional crystal growth. In addition to euhedral crystals, anhedral droplets were observed to form during run No. 2 & 3 suggesting deposition as a liquid as opposed to solid crystals. Synthesis of crystals from a pure NiS compound as opposed to that of natural composition may improve the quality of the resulting crystals and better constrain the ideal growth temperature.
{"title":"Growth of single crystals of crowningshieldite (α-NiS) by chemical-vapour transport","authors":"Thomas E. Gore","doi":"10.1016/j.jcrysgro.2024.127912","DOIUrl":"10.1016/j.jcrysgro.2024.127912","url":null,"abstract":"<div><div>Single crystals of crowningshieldite (α-NiS) were synthesized in three runs <em>via</em> chemical-vapour transport (CVT) over a 20 cm horizontal gradient of 700 → 600 °C (No. 1) and 800 → 700 °C (No. 2 & 3) in evacuated fused silica capsules using natural millerite from Coleman mine in Sudbury, Ontario, Canada with the composition (Ni<sub>0.976</sub>Fe<sub>0.013</sub>Co<sub>0.003</sub>)<sub>Σ0.992</sub>S and I<sub>2</sub> as a transport reagent. Products were characterized <em>via</em> PXRD and SEM methods. Resultant crystals are euhedral, 10 to 400 μm in diameter, and occur as three distinct populations: 1) platy crystals exhibiting dominant pinacoid {<span><math><mrow><mn>0001</mn></mrow></math></span>} and minor dipyramid {<span><math><mrow><mn>10</mn><mover><mrow><mn>1</mn></mrow><mrow><mo>¯</mo></mrow></mover><mn>1</mn></mrow></math></span>}; 2) equant crystals with equal development of both the pinacoid {<span><math><mrow><mn>0001</mn></mrow></math></span>} and dipyramid {<span><math><mrow><mn>10</mn><mover><mrow><mn>1</mn></mrow><mrow><mo>¯</mo></mrow></mover><mn>1</mn></mrow></math></span>}; and 3) blocky crystals showing only the dipyramid {<span><math><mrow><mn>10</mn><mover><mrow><mn>1</mn></mrow><mrow><mo>¯</mo></mrow></mover><mn>1</mn></mrow></math></span>}. The largest crystals were produced at higher temperatures, but experiments lasting longer than 12 days did not result in significant additional crystal growth. In addition to euhedral crystals, anhedral droplets were observed to form during run No. 2 & 3 suggesting deposition as a liquid as opposed to solid crystals. Synthesis of crystals from a pure NiS compound as opposed to that of natural composition may improve the quality of the resulting crystals and better constrain the ideal growth temperature.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"648 ","pages":"Article 127912"},"PeriodicalIF":1.7,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419155","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}
<div><div>Gallium oxide crystals are semitransparent semiconductors with good optical and electrical properties, which allow their use for several technological applications. During the growth process of β-<span><math><mrow><msub><mrow><mi>Ga</mi></mrow><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span> crystals, internal radiation plays a crucial role that affects the growth process and then the crystal quality. In this work, the effect of the melt and the crystal transparency on the vertical Bridgman growth of β-<span><math><mrow><msub><mrow><mi>Ga</mi></mrow><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span> oxide is thoroughly studied. Using a global 2D/3D finite element model, temperature, melt flow, melt-crystal interface, and three-dimensional anisotropic thermal stress are computed at different growth stages. At each stage, four cases are considered, namely, opaque melt and crystal, semi-transparent melt and opaque crystal, semitransparent crystal and opaque melt, and finally semitransparent melt and crystal. The role of internal radiation in each case at different growth stages is then highlighted separately and then coupled together. It was found that the melt-crystal interface is shifted from a convex shape at the early stage to a nearly plane and then to a concave shape at the last stage. The melt flow is then changed from two rolls pattern at the beginning to a single-roll structure at the last stage. Thermal stress of the as-grown ingot is decreased during the growth due to the decrease of temperature non-linearities. Internal radiation inside the crystal acts to increase the melt-crystal interface convexity at the early and middle stages of the growth process and leads to a decrease in its concavity at the final stage. However, the melt transparency leads to the opposite effects, i.e., it decreases the interface convexity at the early stage and increases the interface concavity at the final stage. As a result, for semitransparent crystal and melt, the interface is between the two previous cases. The calculated thermal stresses are found to be more affected by the transparency of the crystal than the melt as the absorption coefficient of β-<span><math><mrow><msub><mrow><mi>Ga</mi></mrow><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span> crystal is smaller than that of the melt. At all stages, the thermal stresses are found to be larger for the opaque case due to the increase of temperature non-linearities in the crystal. Large values are found at the bottom and the lower part of the periphery. Furthermore, internal radiation inside the melt plays a major role during the early growth stage due to the large liquid volume. It reduces the melt flow intensity close to the free surface where the shear stress is combined with the buoyant force and leads to the flattening of the interface decreasing then the radial temperature gradients, which leads to small attenuation of the t
{"title":"Internal radiation effect on semiconductor β-Ga2O3 crystals grown by the VB Method and anisotropic thermal stress","authors":"Azeddine Chayab Draa , Faiza Mokhtari , Idir Lasloudji , Samir Zermout , Kheirreddine Lebbou","doi":"10.1016/j.jcrysgro.2024.127910","DOIUrl":"10.1016/j.jcrysgro.2024.127910","url":null,"abstract":"<div><div>Gallium oxide crystals are semitransparent semiconductors with good optical and electrical properties, which allow their use for several technological applications. During the growth process of β-<span><math><mrow><msub><mrow><mi>Ga</mi></mrow><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span> crystals, internal radiation plays a crucial role that affects the growth process and then the crystal quality. In this work, the effect of the melt and the crystal transparency on the vertical Bridgman growth of β-<span><math><mrow><msub><mrow><mi>Ga</mi></mrow><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span> oxide is thoroughly studied. Using a global 2D/3D finite element model, temperature, melt flow, melt-crystal interface, and three-dimensional anisotropic thermal stress are computed at different growth stages. At each stage, four cases are considered, namely, opaque melt and crystal, semi-transparent melt and opaque crystal, semitransparent crystal and opaque melt, and finally semitransparent melt and crystal. The role of internal radiation in each case at different growth stages is then highlighted separately and then coupled together. It was found that the melt-crystal interface is shifted from a convex shape at the early stage to a nearly plane and then to a concave shape at the last stage. The melt flow is then changed from two rolls pattern at the beginning to a single-roll structure at the last stage. Thermal stress of the as-grown ingot is decreased during the growth due to the decrease of temperature non-linearities. Internal radiation inside the crystal acts to increase the melt-crystal interface convexity at the early and middle stages of the growth process and leads to a decrease in its concavity at the final stage. However, the melt transparency leads to the opposite effects, i.e., it decreases the interface convexity at the early stage and increases the interface concavity at the final stage. As a result, for semitransparent crystal and melt, the interface is between the two previous cases. The calculated thermal stresses are found to be more affected by the transparency of the crystal than the melt as the absorption coefficient of β-<span><math><mrow><msub><mrow><mi>Ga</mi></mrow><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span> crystal is smaller than that of the melt. At all stages, the thermal stresses are found to be larger for the opaque case due to the increase of temperature non-linearities in the crystal. Large values are found at the bottom and the lower part of the periphery. Furthermore, internal radiation inside the melt plays a major role during the early growth stage due to the large liquid volume. It reduces the melt flow intensity close to the free surface where the shear stress is combined with the buoyant force and leads to the flattening of the interface decreasing then the radial temperature gradients, which leads to small attenuation of the t","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"648 ","pages":"Article 127910"},"PeriodicalIF":1.7,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419072","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}
The aim of the work was to study effectiveness of the influence of a new type crystal seed with different microcrystals dispersion on the process of sucrose crystallization and sugar quality. The dispersion of microcrystals of the crystal-forming agent with whole crystals was determined and curves of their differential distribution were presented, which showed the average particle sizes of the “Ester K 01” are 18.2 μm and 46.4 μm. The morphological characteristics were determined of particles of the whole crystals seed and the seed slurry produced at a sugar factory. The duration of massecuite boiling was investigated and a comparative characterization of the quality indicators of the resulting massecuite, mother liquor, and sugar was given depending on the use of the whole crystals seed with different dispersion of microcrystals in comparison with the factory slurry. Microphotographs of sugar crystals in the massecuite were obtained with their size recorded 5, 10 and 20 min after the input of various seeds. The morphology of sugar crystals was studied in the finished massecuite. A comparison is given of the granulometric composition of sugar crystals obtained with crystal-forming agents with different dispersion. It was found based on the results of the study that when using the “Ester K 01” (46.4 μm) in thick juice with high turbidity the corresponding crystals are formed faster in the total amount of the massecuite. It was also found that there is a kind of blocking of the process of adjacent growth of crystals from the particles of impurities of thick juice with high turbidity. This contributes to the formation of more uniform, homogeneous crystals of the correct shape. The results are presented in the article of tests of the whole crystal seed “Ester K 01” (18.2 μm) and “Ester K 01” (46.4 μm) at sugar factories using the method of working on the seed magma and the method of shock crystallization respectively. The dependences were obtained of the average linear size, the amount of sugar of the 0.65 mm fraction, the coefficient of variation and the coefficient of uniformity of sugar crystals on the consumption of the whole crystals seed “Ester K 01” (crystal size 46.4 μm). The regression equation was developed in natural form for the process of sucrose shock crystallization. It was established the rational consumption of the crystal-forming agent “Ester K 01” (crystal size 46.4 μm), which ensures the effective crystallization of sucrose for the process of crystallization by the shock induced method.
这项工作的目的是研究具有不同微晶分散度的新型结晶种子对蔗糖结晶过程和蔗糖质量的影响效果。测定了晶体形成剂的微晶与整粒晶体的分散情况，并绘制了它们的差异分布曲线，结果表明 "酯 K 01 "的平均粒径分别为 18.2 μm 和 46.4 μm。对全晶种子和糖厂生产的种子浆液的颗粒形态特征进行了测定。研究了糖化沸腾的持续时间，并根据使用具有不同微晶分散度的全结晶种子与工厂浆料的情况，对所得糖化沸腾液、母液和糖的质量指标进行了比较。在输入不同的种子 5、10 和 20 分钟后，获得了糖浆液中糖晶体的显微照片，并记录了它们的大小。研究了成品糖浆中糖晶体的形态。比较了使用不同分散度的晶体形成剂所获得的糖晶体的粒度组成。根据研究结果发现，在稠度较高的果汁中使用 "酯 K 01"（46.4 μm）时，相应的晶体在糖渣总量中的形成速度较快。研究还发现，高浊度稠果汁中的杂质颗粒在晶体相邻生长过程中会受到某种阻碍。这有助于形成形状更均匀一致的晶体。文章介绍了在制糖厂分别使用岩浆种子工作法和冲击结晶法对 "Ester K 01"（18.2 μm）和 "Ester K 01"（46.4 μm）全晶体种子进行测试的结果。得出了 "酯 K 01"（晶体大小为 46.4 μm）整个晶体种子消耗量的平均线性大小、0.65 mm 部分的含糖量、变异系数和糖晶体均匀性系数的相关性。蔗糖震荡结晶过程的回归方程是以自然形式建立的。确定了晶体形成剂 "酯 K 01"（晶体大小为 46.4 μm）的合理消耗量，从而确保了蔗糖在冲击诱导法结晶过程中的有效结晶。
{"title":"Influence of dispersion of a new type whole crystals seed on crystallization process and sugar quality","authors":"Serhii Volodymyrovych Tkachenko , Tamila Volodymyrivna Sheiko , Olena Mykhailivna Anisimova , Vasyl Viktorovych Petrenko , Kostiantyn Dmytrovych Skoryk , Olha Illivna Dzhohan , Liubomyr Mykhailovych Khomichak , Inha Vadymyrivna Kuznietsova","doi":"10.1016/j.jcrysgro.2024.127909","DOIUrl":"10.1016/j.jcrysgro.2024.127909","url":null,"abstract":"<div><div>The aim of the work was to study effectiveness of the influence of a new type crystal seed with different microcrystals dispersion on the process of sucrose crystallization and sugar quality. The dispersion of microcrystals of the crystal-forming agent with whole crystals was determined and curves of their differential distribution were presented, which showed the average particle sizes of the “Ester K 01” are 18.2 μm and 46.4 μm. The morphological characteristics were determined of particles of the whole crystals seed and the seed slurry produced at a sugar factory. The duration of massecuite boiling was investigated and a comparative characterization of the quality indicators of the resulting massecuite, mother liquor, and sugar was given depending on the use of the whole crystals seed with different dispersion of microcrystals in comparison with the factory slurry. Microphotographs of sugar crystals in the massecuite were obtained with their size recorded 5, 10 and 20 min after the input of various seeds. The morphology of sugar crystals was studied in the finished massecuite. A comparison is given of the granulometric composition of sugar crystals obtained with crystal-forming agents with different dispersion. It was found based on the results of the study that when using the “Ester K 01” (46.4 μm) in thick juice with high turbidity the corresponding crystals are formed faster in the total amount of the massecuite. It was also found that there is a kind of blocking of the process of adjacent growth of crystals from the particles of impurities of thick juice with high turbidity. This contributes to the formation of more uniform, homogeneous crystals of the correct shape. The results are presented in the article of tests of the whole crystal seed “Ester K 01” (18.2 μm) and “Ester K 01” (46.4 μm) at sugar factories using the method of working on the seed magma and the method of shock crystallization respectively. The dependences were obtained of the average linear size, the amount of sugar of the 0.65 mm fraction, the coefficient of variation and the coefficient of uniformity of sugar crystals on the consumption of the whole crystals seed “Ester K 01” (crystal size 46.4 μm). The regression equation was developed in natural form for the process of sucrose shock crystallization. It was established the rational consumption of the crystal-forming agent “Ester K 01” (crystal size 46.4 μm), which ensures the effective crystallization of sucrose for the process of crystallization by the shock induced method.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"648 ","pages":"Article 127909"},"PeriodicalIF":1.7,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419073","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}
The effect of magnesium co-doping on growth conditions, crystal composition, optical and spectral properties of manganese or chromium-doped Ca3(VO4)2 (CVO) crystal was studied. The single crystals were grown by the Czochralski method. Effective segregation coefficients of manganese and chromium in the CVO matrix with magnesium co-doping were calculated. A redistribution of the absorption lines intensities was observed in the absorption spectra of CVO:Mn:Mg and CVO:Cr:Mg. Low (15 K) temperature fluorescence measurements confirmed that co-doping CVO crystal with Mg ions leads to the redistribution of Mn ions concentration in different valence states, but does not cause changes in their spectral properties. In the presence of magnesium, additional annealing of the materials resulted in a slower reduction of the valence state of doping ions and a noticeable change in crystal coloration. All investigated impurities have practically no effect on the specific ferroelectric domain structure of CVO.
{"title":"The effect of magnesium impurities on the optical and spectral characteristics of calcium orthovanadate single crystals doped with chromium and manganese","authors":"I.S. Voronina , M.E. Doroshenko , E.E. Dunaeva , S.S. Zykova , L.D. Iskhakova , L.I. Ivleva","doi":"10.1016/j.jcrysgro.2024.127908","DOIUrl":"10.1016/j.jcrysgro.2024.127908","url":null,"abstract":"<div><div>The effect of magnesium co-doping on growth conditions, crystal composition, optical and spectral properties of manganese or chromium-doped Ca<sub>3</sub>(VO<sub>4</sub>)<sub>2</sub> (CVO) crystal was studied. The single crystals were grown by the Czochralski method. Effective segregation coefficients of manganese and chromium in the CVO matrix with magnesium co-doping were calculated. A redistribution of the absorption lines intensities was observed in the absorption spectra of CVO:Mn:Mg and CVO:Cr:Mg. Low (15 K) temperature fluorescence measurements confirmed that co-doping CVO crystal with Mg ions leads to the redistribution of Mn ions concentration in different valence states, but does not cause changes in their spectral properties. In the presence of magnesium, additional annealing of the materials resulted in a slower reduction of the valence state of doping ions and a noticeable change in crystal coloration. All investigated impurities have practically no effect on the specific ferroelectric domain structure of CVO.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"648 ","pages":"Article 127908"},"PeriodicalIF":1.7,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419070","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}
This study employed quantum chemical methods to predict and synthesize three luminescent cocrystals. Utilizing Triphenylene as the electron donor and 1,2,4,5-tetracyanobenzene (TCNB), 2,3,5,6-tetrafluoroterephthalonitrile (TFP), and 2,3,5,6-tetrachloroterephthalonitrile (TCP) as acceptors, the structures and internal interactions of these cocrystals were analyzed. The predominant interactions observed were charge transfer, hydrogen bonding, and π-π interactions. Notably, the Triphenylene-TCP cocrystal exhibited a significantly extended fluorescence lifetime compared to the other two. Further investigations, employing time-dependent density functional theory (TD-DFT) on Triphenylene-TCP, suggested that intersystem crossing (ISC) and reverse intersystem crossing (RISC) mechanisms contribute to the prolonged fluorescence lifetime. This study offers valuable insights into the design of supramolecular cocrystals to enhance the performance of organic fluorescent materials.
{"title":"Quantum chemistry − guided design of luminescent Triphenylene − based co-crystals: Unveiling heavy atom for enhanced fluorescence lifetime","authors":"Yidan Xie, Pengfei Wu, Wenxiu Yao, Xinyu Shen, Shuwei Xia, Liangmin Yu","doi":"10.1016/j.jcrysgro.2024.127907","DOIUrl":"10.1016/j.jcrysgro.2024.127907","url":null,"abstract":"<div><div>This study employed quantum chemical methods to predict and synthesize three luminescent cocrystals. Utilizing Triphenylene as the electron donor and 1,2,4,5-tetracyanobenzene (TCNB), 2,3,5,6-tetrafluoroterephthalonitrile (TFP), and 2,3,5,6-tetrachloroterephthalonitrile (TCP) as acceptors, the structures and internal interactions of these cocrystals were analyzed. The predominant interactions observed were charge transfer, hydrogen bonding, and π-π interactions. Notably, the Triphenylene-TCP cocrystal exhibited a significantly extended fluorescence lifetime compared to the other two. Further investigations, employing time-dependent density functional theory (TD-DFT) on Triphenylene-TCP, suggested that intersystem crossing (ISC) and reverse intersystem crossing (RISC) mechanisms contribute to the prolonged fluorescence lifetime. This study offers valuable insights into the design of supramolecular cocrystals to enhance the performance of organic fluorescent materials.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"648 ","pages":"Article 127907"},"PeriodicalIF":1.7,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419156","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 : 2024-09-27DOI: 10.1016/j.jcrysgro.2024.127904
Youness El Haimer , Anouar Rich , Sara Mountadar , Mostapha Siniti , Soufiane Tahiri , Mohammed Mountadar , Denis Mangin
This work aims to develop a process for treating olive mill wastewater (OMW) using cryoconcentration. The experiments are carried out in two stages: the freezing stage, producing an ice at temperatures between −16 °C and −24 °C, and the sweating stage, conducted at room temperature. This second step consists in purifying in depth the ice by melting the impure zones of concentrated solutions pockets. Three to five liquid fractions with decreasing concentrations of solute were then collected. The physicochemical analysis indicates that as the initial concentration of the solution increases, the concentration efficiency in the first fraction decreases, and the final ice block is less pure. The parametric study, conducted using the Response Surface methodology (RSM), highlighted the effects of initial concentration, freezing temperature and the number of liquid fraction applied during the partial melting of the ice on the concentration of total phenols in the first liquid fraction obtained. The initial concentration and the fractional partial melting step have a very significant impact. However, within the studied range of cooling temperatures, −16 °C results in a slight increase in the recovery efficiency of phenolic compounds compared to −24 °C. Overall, the results demonstrate the feasibility of the process, which enables the recovery of cryoconcentrated solutions rich in total phenols and the production of good-quality water.
这项工作旨在开发一种利用低温浓缩处理橄榄油厂废水（OMW）的工艺。实验分两个阶段进行：冷冻阶段，在-16 °C至-24 °C的温度下结冰；发汗阶段，在室温下进行。第二步是通过融化浓缩溶液袋中的不纯区域，对冰进行深度净化。然后收集三到五个溶质浓度递减的液体馏分。物理化学分析表明，随着溶液初始浓度的增加，第一部分的浓缩效率降低，最终冰块的纯度降低。采用响应面法（RSM）进行的参数研究突出显示了初始浓度、冷冻温度和部分融冰过程中使用的液体馏分数量对所获得的第一液体馏分中总酚浓度的影响。初始浓度和部分融化步骤的次数会产生非常显著的影响。不过，在所研究的冷却温度范围内，-16 °C 与 -24 °C 相比，酚类化合物的回收效率略有提高。总之，研究结果证明了该工艺的可行性，它可以回收富含总酚的低温浓缩溶液并生产优质水。
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Pub Date : 2024-09-26DOI: 10.1016/j.jcrysgro.2024.127901
Li Weidong , Zhang Meng
Lanthanum (La)-doped SiC nanowires (NMs) were synthesized via a carbon thermal reduction process using different graphite powders, while milled Si-SiO2 mixed powders were employed as the silicon source. The identification of the products as β-SiC were supported by Select-area electron diffraction (SAED) and X-ray diffraction (XRD) analysis. The field emission results demonstrated that the turn-on field reached a minimum value of approximately 2.3 V/μm when the graphite content ranged from 2.5 g–3 g. The product exhibited higher density at this stage, accompanied by an increase in nanowire diameter and a tendency toward straightness. The energy spectrum analysis revealed a significant increase in the lanthanum content within the nanowires, with the atomic percentage rising from 0.05 to 0.26–0.27. The synergistic effect of morphology and La improved the field emission performance of the product. The findings may offer valuable insights for enhancing the field emission performance of one-dimensional nanomaterials.
使用不同的石墨粉，通过碳热还原工艺合成了掺有镧 (La) 的碳化硅纳米线 (NMs)，同时使用研磨的 Si-SiO2 混合粉末作为硅源。通过选区电子衍射（SAED）和 X 射线衍射（XRD）分析，确定了产品为 β-SiC 。场发射结果表明，当石墨含量在 2.5 g-3 g 之间时，开启场达到最小值，约为 2.3 V/μm。能谱分析表明，纳米线中的镧含量显著增加，原子百分比从 0.05 上升到 0.26-0.27。形态和镧的协同作用提高了产品的场发射性能。这些发现为提高一维纳米材料的场发射性能提供了宝贵的启示。
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