Materials Letters最新文献_第5页

Enhanced photoluminescence of CdTe/SiO2 quantum dots: Impact of ambient conditions and laser excitation regime on surface trap passivation CdTe/SiO2量子点的增强光致发光：环境条件和激光激发方式对表面阱钝化的影响

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-19 DOI: 10.1016/j.matlet.2025.138968

D.S. Daibagya , S.A. Ambrozevich , M.S. Smirnov , O.V. Ovchinnikov , A.V. Osadchenko , I.A. Zakharchuk , A.S. Selyukov

{"title":"Enhanced photoluminescence of CdTe/SiO2 quantum dots: Impact of ambient conditions and laser excitation regime on surface trap passivation","authors":"D.S. Daibagya , S.A. Ambrozevich , M.S. Smirnov , O.V. Ovchinnikov , A.V. Osadchenko , I.A. Zakharchuk , A.S. Selyukov","doi":"10.1016/j.matlet.2025.138968","DOIUrl":"10.1016/j.matlet.2025.138968","url":null,"abstract":"<div><div>We study the photoluminescence properties of CdTe/SiO<sub>2</sub> spherical quantum dots (QDs) under different ambient conditions and excitation regimes. Our findings reveal a significant increase in photoluminescence intensity over time, which we attribute to the adsorption of oxygen and water molecules at QD interfaces resulting in trap passivation. This enhancement is more pronounced under continuous laser excitation compared to periodic on/off excitation, suggesting that continuous excitation facilitates more efficient surface chemistry and trap passivation. The proposed mechanism involving adsorption of oxygen and water is supported by the fact that photoluminescence intensity enhancement at continuous irradiation is smaller at evacuation. Additionally, we observe that the average luminescence lifetime decreases with time at continuous laser irradiation in between the decay measurements, indicating improved electron-hole recombination efficiency due to trap passivation. These insights into the photoluminescence behavior of CdTe/SiO<sub>2</sub> QDs under different ambient conditions and excitation regimes contribute to the understanding of QD photostability and the development of QD-based devices.</div></div>","PeriodicalId":384,"journal":{"name":"Materials Letters","volume":"398 ","pages":"Article 138968"},"PeriodicalIF":2.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366007","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}

引用次数: 0

Friction stir welding parameters for improved joint integrity in dissimilar-thickness Al-Mg-Sc alloys 提高不同厚度Al-Mg-Sc合金接头完整性的搅拌摩擦焊接参数

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-19 DOI: 10.1016/j.matlet.2025.138960

Arthur de Bribean Guerra, Guilherme Yuuki Koga, Claudemiro Bolfarini

{"title":"Friction stir welding parameters for improved joint integrity in dissimilar-thickness Al-Mg-Sc alloys","authors":"Arthur de Bribean Guerra, Guilherme Yuuki Koga, Claudemiro Bolfarini","doi":"10.1016/j.matlet.2025.138960","DOIUrl":"10.1016/j.matlet.2025.138960","url":null,"abstract":"<div><div>This study explores the friction stir welding (FSW) of AlMgSc alloys with an emphasis on process parameter optimization and mechanical performance evaluation. A robotic FSW setup equipped with a conical triflat threaded pin was used to join sheets of dissimilar thickness under varying welding conditions. Optimal parameters produced defect-free joints that retained up to 94% of the base material’s yield strength. Microstructural analysis identified oxide agglomeration at the thermo-mechanically affected zone (TMAZ)–nugget interface—particularly on the advancing side—as a key contributor to failure, whereas successful joints exhibited fragmented oxide layers that reduced the risk of brittle fracture. Microhardness mapping revealed asymmetric hardness profiles, indicating strain localization and non-uniform material flow. Fractographic analysis showed mixed-mode fracture mechanisms influenced by oxide distribution and weld zone morphology. These results underscore the importance of oxide control, the potential benefits of asymmetric tool design, and the value of post-weld treatments to improve joint ductility and reliability.</div></div>","PeriodicalId":384,"journal":{"name":"Materials Letters","volume":"398 ","pages":"Article 138960"},"PeriodicalIF":2.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364373","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}

引用次数: 0

Encapsulation of zinc porphyrin within a tetraprismatic molecular cage as efficient light sensitizer and single-site photocatalyst 在四棱镜分子笼内包封卟啉锌作为高效光敏剂和单位点光催化剂

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-19 DOI: 10.1016/j.matlet.2025.138971

Xi-Han Li, Chao-Yu Wang, Dong-Jin Qian

引用次数: 0

Effect of carboxyl moiety on the electrochromic properties of 1,1′-dibenzyl-4,4′-bipyridinium salt 羧基部分对1,1′-二苯基-4,4′-联吡啶盐电致变色性能的影响

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-19 DOI: 10.1016/j.matlet.2025.138963

Meng Wang, Zhuangzhuang Yang, Lu Lu, Debao Xiao

{"title":"Effect of carboxyl moiety on the electrochromic properties of 1,1′-dibenzyl-4,4′-bipyridinium salt","authors":"Meng Wang, Zhuangzhuang Yang, Lu Lu, Debao Xiao","doi":"10.1016/j.matlet.2025.138963","DOIUrl":"10.1016/j.matlet.2025.138963","url":null,"abstract":"<div><div>Viologen exhibits excellent comprehensive electrochromic properties including optical contrast, coloration efficiency, response time and cycling stability. Herein, the electrochromic properties of 1,1′-bis(4-carboxyl-benzyl)-4,4′-bipyridiniumdibromide were examined <em>via</em> introducing carboxyl moiety onto benzyl group. The solutions of this compound and benzyl viologen were sandwiched into electrochromic devices and their electrochromic properties were compared. We found that carboxylic moiety facilitates benzyl viologen to exhibit increased coloration efficiency up to 165.9 cm<sup>2</sup>/C with comparison to that of 131.6 cm<sup>2</sup>/C without this group. The optical contrast, ΔT, reaches up to 74.6 % for the carboxylic product while that of 61.3 % was obtained without this group. The optical contrast of carboxylic product monitored at 607 nm for 1000 cycles retained 93.3 % of its initial value, which is larger than that of 69.8 % without modification, indicating that the cycling stability is enhanced by carboxylic moiety. This work demonstrated that carboxylic group can improve the overall electrochromic performance of benzyl viologen.</div></div>","PeriodicalId":384,"journal":{"name":"Materials Letters","volume":"398 ","pages":"Article 138963"},"PeriodicalIF":2.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322860","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}

引用次数: 0

Energetic stability of small defect clusters in α-zirconium by first-principles calculation 用第一性原理计算α-锆中小缺陷团簇的能量稳定性

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-18 DOI: 10.1016/j.matlet.2025.138958

Wenlong Liu , Chen Zhang , Yizhuo Zhang , Zhipeng Sun , Yaolin Zhao , Chenyang Lu , Tan Shi , Fanqiang Meng , Yuanming Li

引用次数: 0

Energy bandgap of ZnSe bulk crystal between 300 K and 1000 K ZnSe块状晶体在300 ~ 1000 K之间的能带隙

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-18 DOI: 10.1016/j.matlet.2025.138955

Ching-Hua Su

引用次数: 0

Honeycomb sample design for high-throughput preparation of RCCAs 蜂窝状样品设计用于高通量制备RCCAs

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-18 DOI: 10.1016/j.matlet.2025.138957

Jiří Kozlík , Eliška Jača , Monika Vilémová , František Lukáč , Tomáš Chráska , Josef Stráský

引用次数: 0

A novel developed plasma processing of optical components in closed chamber without aggressive reagents: Polishing performance, removal analysis and its characterization 一种新型的光学元件在封闭腔室中无腐蚀剂等离子体加工：抛光性能、去除分析及其表征

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-18 DOI: 10.1016/j.matlet.2025.138959

Hari Narayan Singh Yadav , Manas Das

{"title":"A novel developed plasma processing of optical components in closed chamber without aggressive reagents: Polishing performance, removal analysis and its characterization","authors":"Hari Narayan Singh Yadav , Manas Das","doi":"10.1016/j.matlet.2025.138959","DOIUrl":"10.1016/j.matlet.2025.138959","url":null,"abstract":"<div><div>Finishing optical components with plasma is emerging as a new trend in advanced manufacturing to provide precise and accurate substrates. The plasma process is a relatively recent technique that has gained widespread use for improving the quality of optical materials due to its many advantages. This study examines MRR and surface roughness changes on both faces of the cuboidal-shape prism. The result reveals that %Δ<em>R<sub>a</sub></em> decreases with increases in the plasma chamber pressure. The maximum and minimum %Δ<em>R<sub>a</sub></em> values are observed to be 372.17 and −61.56 for polished surfaces at 5 and 50 mbar plasma chamber pressure, respectively. Meanwhile, the maximum and minimum observed values for lapped surfaces are 24.5 and −1.01 at 5 and 50 mbar plasma chamber pressure, respectively. Surface morphology investigations demonstrated that micro-cracks, scratches, and defects are decreased after MPPP. EDX analysis shows the occurrence of elements, signifying reactions on plasma processed surface. Additionally, elemental mapping is used to verify the distribution of all constituent elements on the processed surfaces.</div></div>","PeriodicalId":384,"journal":{"name":"Materials Letters","volume":"398 ","pages":"Article 138959"},"PeriodicalIF":2.7,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330189","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}

引用次数: 0

Corrosion behavior of micro-arc oxidation coatings modified by laser remelting on 6063 aluminum alloy 6063铝合金激光重熔改性微弧氧化涂层的腐蚀行为

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-18 DOI: 10.1016/j.matlet.2025.138935

Chao Wang , Yunjie Ge , Bo Jiang , Renguo Song

引用次数: 0

Analysis of wear tracks and mechanical properties evaluation of TiO2 and Al2O3 reinforced hybrid epoxy composites TiO2和Al2O3增强杂化环氧复合材料的磨损轨迹分析及力学性能评价

IF 2.7 4区材料科学

Materials Letters Pub Date : 2025-06-18 DOI: 10.1016/j.matlet.2025.138953

Balu Maloth , Votarikari Naveen Kumar

引用次数: 0