{"title":"Dimensional downscaling and quantum engineering: A path to high-performance micro-LEDs","authors":"Shazma Ali, Muhammad Usman","doi":"10.1016/j.jlumin.2024.120951","DOIUrl":"10.1016/j.jlumin.2024.120951","url":null,"abstract":"<div><div>The investigation of the optoelectronic performance of AlGaN-based ultraviolet-C (UV-C) micro light-emitting diodes (μLEDs) emitting at 273 nm is carried out numerically by reducing the chip area from large LED (300 × 300 μm<sup>2</sup>) to μLED (25 × 25 μm<sup>2</sup>). However, due to the high surface to volume ratio of μLED, surface recombination becomes dominant that is generated due to robust sidewall defects. The enhanced current spreading in μLED further affects the carrier injection in the active region as the electrons and holes are captured by sidewall defects. These effects are more dominant at low current density in μLED while at high current density, the sidewall defects get saturated, and the surface recombination weakens. Various optimization strategies, such as quantum wells (QWs) width, quantum barriers (QBs) width, and QW number are carried out to study the effect on the performance of 25 × 25 μm<sup>2</sup> UV-C μLED. These optimization strategies at low current density (0.1 A/cm<sup>2</sup>) further improved the electrical/optical properties of AlGaN-based UV-C μLEDs.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120951"},"PeriodicalIF":3.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dual-phase Cs4PbBr6/CsPbBr3 perovskite quantum dot borosilicate glass for WLED applications","authors":"Zhigang Yang, Shuqin Zhang, Junshuai Chen, Tianqing Sheng, Xinran Lv, Xuguang Wei, Guoqiang Qin, Gang Yu","doi":"10.1016/j.jlumin.2024.120953","DOIUrl":"10.1016/j.jlumin.2024.120953","url":null,"abstract":"<div><div>Owing to inherent structural instability of perovskite quantum dots, they are instability in humid environments and high temperatures conditions. To address this issue, a simple, environmentally friendly glass encapsulated technology is used to protect the perovskite quantum dots. Meanwhile, the dual-phase perovskite structure realized by phase transition engineering can further increase the stability of perovskite quantum dots. In this study, 3D CsPbBr<sub>3</sub>/0D Cs<sub>4</sub>PbBr<sub>6</sub> dual-phase coexisting perovskite quantum dot glass powders were synthesized through melt quenching and subsequent crystallization induction of thermal treatment and water molecule, respectively. Results showed that compared with thermal treatment induction, perovskite QDs glass powders by water molecules induction exhibited a high PLQY of 24.7 % with a central wavelength of 519 nm and displayed excellent environmental stability. By combining green fluorescence from 3D CsPbBr<sub>3</sub>/0D Cs<sub>4</sub>PbBr<sub>6</sub> QDs glass powders and red fluorescence powders (CaAlSiN<sub>3</sub>:Eu), a WLED device with an impressive EQE of 20.6 % was created, indicating a promising application potential.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120953"},"PeriodicalIF":3.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B.U. Mendoza Enriquez , Miriam Rangel , Y. Kumar , S. Khandual , V. Agarwal
{"title":"Algae derived carbon dots and its polymeric composites for white light emission","authors":"B.U. Mendoza Enriquez , Miriam Rangel , Y. Kumar , S. Khandual , V. Agarwal","doi":"10.1016/j.jlumin.2024.120955","DOIUrl":"10.1016/j.jlumin.2024.120955","url":null,"abstract":"<div><div>Nanomaterials with multicolor emission have been of great interest due to their versatility. Recently, environmentally friendly carbon dots (CDs) with excitation wavelength/solvent/dopant dependent emission have been used for designing different types of white light emitting diodes (W-LED). In this work, single-green precursor (<em>Arthrospira platensis</em>) derived CDs from a one-step hydro/solvothermal synthesis, have been implemented in the elaboration of W-LEDs. The white emission of CDs was modulated by the solvent engineering and doping strategies. A CDs/PVA composite based W-LED with a color render index (CRI) upper to ∼90 %, Commission Internationale Eclairage (CIE) coordinates of (0.31, 0.33) and correlated color temperature (CCT) of <span><math><mrow><mo>∼</mo></mrow></math></span> 6500 K is demonstrated. These findings suggest that white CDs derived from <em>A. platensis</em> possess promising potential in the field of optoelectronic devices, especially in the production of efficient and high-quality white illumination.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120955"},"PeriodicalIF":3.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Siyu Hou , Baowen Wang , Yan Zhang , Hui Chang , Xingqiang Lü , Guorui Fu , Hongyang Zhang
{"title":"Geometrically isomeric [Ir(C^N)(C’^N’)(N’’^O)-tris-heteroleptic [Ir(dFppy)(CN-ppz)(pic)] Ir(III)-complexes with blue-light: Forwards to efficient blue organic light-emitting diodes","authors":"Siyu Hou , Baowen Wang , Yan Zhang , Hui Chang , Xingqiang Lü , Guorui Fu , Hongyang Zhang","doi":"10.1016/j.jlumin.2024.120949","DOIUrl":"10.1016/j.jlumin.2024.120949","url":null,"abstract":"<div><div>Despite the great success of Ir(III)-complex-based green/red-light OLEDs (OLED = organic light-emitting diode), the realization of their efficient blue-OLEDs is far behind and challenging. Herein, using <strong>HdFppy</strong> (2-(2,4-difluorophenyl)pyridine) and <strong>CN-ppzH</strong> (4-(1<em>H</em>-pyrazol-1-yl)benzonitrile) as the HC^N/HC’^N’ ligands and <strong>Hpic</strong> (2-picolinic acid) as the N’’^O-ancillary ligand, the [Ir(C^N)(C’^N’)(N’’^O)]-<em>tris</em>-heteroleptic molecular design strategy was adopted, obtaining the two [Ir(dFppy)(CN-ppz)(pic)]-configured blue-emitting (<em>λ</em><sub>PL</sub> (photoluminescence emission peak) = 466, 496(sh) nm; <em>Φ</em><sub>PL</sub> (photoluminescence quantum efficiency) = 0.41–0.46) geometrical isomers <strong>1a</strong> and <strong>1b</strong>. Further through the doped and vacuum-deposited fabrication, their <strong>blue-OLEDs-1A/1B</strong> with the <em>L</em><sup>Max</sup> (maximum luminance) values up to 18090–22528 cd/m<sup>2</sup> and the <em>η</em><sub>EQE</sub><sup>Max</sup> (maximum external quantum efficiency) sizes of 7.99–8.42 %, were realized, respectively. This study result shows that [Ir(dFppy)(CN-ppz)(pic)]-included [Ir(C^N)(C’^N’)(N’’^O)]-<em>tris</em>-heteroleptic Ir(III)-complexes can be used as the attractive blue-phosphor candidates forwards to efficient blue-OLEDs.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120949"},"PeriodicalIF":3.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stokes and anti-Stokes emission characteristics of Er3+/Yb3+ co-doped zinc tellurite glasses under 377 and 1550 nm excitations for solar energy conversion application","authors":"Keenatampalle Suresh , C.R. Kesavulu , C.J. Deviprasad , Wisanu Pecharapa , Upendra Kumar Kagola , Th Tröster , C.K. Jayasankar","doi":"10.1016/j.jlumin.2024.120948","DOIUrl":"10.1016/j.jlumin.2024.120948","url":null,"abstract":"<div><div>One of the best rare earth combinations for down- and up-converting the solar photons is Er<sup>3+</sup>/Yb<sup>3+</sup>. Therefore, at present, by using the traditional melt quench technique, zinc tellurite glasses doped with Er<sup>3+</sup> and Er<sup>3+</sup>/Yb<sup>3+</sup> were characterised. Several methods of down-conversion that result in the emission of 1000 nm from the acceptor (Yb<sup>3+</sup>) under excitation of donor (Er<sup>3+</sup>) were studied. On the other hand, the impact of acceptor (Yb<sup>3+</sup>) concentration and excitation pump power on the excited state absorption and its influence on the up-conversion emission (1000 nm) properties were investigated in detail under 1535 nm excitation. The studies on emission and decay results are discovered to be very significant. Suggesting that these glasses when used as conversion layers, can append the conversion efficiency of Si-based solar cells.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120948"},"PeriodicalIF":3.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cobalt/Aluminum layered double hydroxide intercalated with rice straw based-biochar for recognizing organophosphates in cereal crops","authors":"Harshita Gupta , Kulwinder Kaur , Irshad Mohiuddin , Raghubir Singh , Varinder Kaur","doi":"10.1016/j.jlumin.2024.120950","DOIUrl":"10.1016/j.jlumin.2024.120950","url":null,"abstract":"<div><div>Herein, rice straw-based biochar was intercalated with Co/Al-LDH (LDH-Biochar) using a green technique based on the co-precipitation method. LDH-Biochar was further evaluated for the naked eye detection and spectrofluorimetric analysis of dibutyl phosphate (DBP), diphenyl phosphate (DPP), and diethyl chlorophosphate (DCP), which are extensively used as pesticides and flame retardants. The material inherited a fluorescent signal with a maximum at 570 nm (λ<sub>exc</sub> = 520 nm) from the precursor ‘biochar’ and porous interactive surface from the precursor ‘LDH.’ It showed selective quenching for the organophosphates, i.e., DBP, DPP, and DCP, with a detection limit of 1.39 μM, 1.17 μM, and 1.29 μM, respectively, and the probe showed good response within the linear range of 1.9–25.3 μM. Furthermore, the method was successfully implemented to extract the organophosphates from wheat, corn, and pearl millet with recoveries in the range of 97.49–101.35 % (RSD; 0.27–3.22 %), 97.08–99.91 % (RSD; 0.27–3.17 %), and 98.18–103.54 % (RSD; 0.19–4.76 %), respectively. The outcome of this research is thus expected to help develop LDH-Biochar as a multi-analyte sensor for organophosphates (DBP, DPP, and DCP), which are extensively used as pesticides and flame retardants.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120950"},"PeriodicalIF":3.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A novel strategy for suppressing blue light hazards of white light-emitting diodes by using transparent bamboo","authors":"Yaling Chai , Xiaorong Yin , Ziquan Guo , Zhong Chen , Caichao Wan","doi":"10.1016/j.jlumin.2024.120942","DOIUrl":"10.1016/j.jlumin.2024.120942","url":null,"abstract":"<div><div>- Light-emitting diode (LED) has become the most popular lighting device in the world, but the harm of blue light brought by LEDs still remains a very important problem. The natural bamboo possesses a unique hierarchical structure and can be treated as an optical management material applied in the photoelectric device after the treatment of lignin removal or lignin modification. In this paper, we have discovered that the blue light hazards of white LEDs can be effectively suppressed after introducing the transparent bamboo (TB) based on above treatment. Five types of white LEDs are adopted for performing this study, and more than 27 % decrease of blue light hazard efficiency can be found after covering the TB processed by lignin modification and polymer impregnation, although more or less optical loss happens. This fact may be attributed to different light scattering effects of TB in the blue band and others in the visible range. After that, the circadian effects of two types of white LEDs (warm white and neutral white) while the TB is covered on them are also discussed. This work provides an effective method for suppressing blue light hazards, regulating circadian effects, and maintaining the color performance of LED lighting as much as possible.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120942"},"PeriodicalIF":3.3,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iu. Nasieka , V. Strel'nitskij , O. Opalev , V. Gritsina , K. Koshevyi , O. Horobei , M. Zablodskyi , V. Lozinskii , V. Temchenko
{"title":"The evolution of micro-photoluminescence spectra of PECVD diamond microcrystals along the vertical growth direction and their dependence on CH4 concentration","authors":"Iu. Nasieka , V. Strel'nitskij , O. Opalev , V. Gritsina , K. Koshevyi , O. Horobei , M. Zablodskyi , V. Lozinskii , V. Temchenko","doi":"10.1016/j.jlumin.2024.120943","DOIUrl":"10.1016/j.jlumin.2024.120943","url":null,"abstract":"<div><div>The changes in the shape of micro-photoluminescence spectra of PECVD diamond micro-crystal measured, depending on the position of the excitation laser spot along the crystallite height, were analyzed. It was ascertained that the processes of SiV defect formation non-monotonically depend on the distance from the Si substrate. At the distances of 2–20 μm the concentration of SiV defects increases, then at distances larger than 20 μm the number of SiV defects decreases. The concentration of NV<sup>−</sup> and NV<sup>0</sup> defects monotonically increases with the distance from the Si substrate. The predomination of SiV defect formation at the beginning stages of the crystal growth is explained by the substantial concentration of carbon vacancies required for their formation. With the increase in the distance from the substrate, the crystalline perfection increases, the concentration of carbon vacancies decreases and the processes of NV<sup>−</sup> and NV<sup>0</sup> defect formation dominate. The increase in CH<sub>4</sub> fraction within 0.75–6 % leads to the increase in the volume fraction of graphite-like carbon, which is the good diffusion channel for Si atoms from the substrate into the plasma. Therefore, the concentration of SiV, NV<sup>−</sup>, and NV<sup>0</sup> defects on the surface of the crystal depends on the volume fraction of graphite-like carbon defined by CH<sub>4</sub> content.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120943"},"PeriodicalIF":3.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Babin , P. Bohacek , A. Krasnikov , M. Nikl , L. Vasylechko , S. Zazubovich
{"title":"Photoluminescence optical and thermal quenching in heavily doped Gd3(Ga,Al)5O12:Ce, Mg single crystals: Dependence on the Ga3+, Ce3+, and Mg2+ concentration","authors":"V. Babin , P. Bohacek , A. Krasnikov , M. Nikl , L. Vasylechko , S. Zazubovich","doi":"10.1016/j.jlumin.2024.120945","DOIUrl":"10.1016/j.jlumin.2024.120945","url":null,"abstract":"<div><div>Heavily doped single crystals of Gd<sub>3</sub>Ga<sub>x</sub>Al<sub>5-x</sub>O<sub>12</sub>:Ce, Mg (x = 2.46–2.95) with different concentrations of Ce (0.016–0.188 at.%) and Mg (0–0.083 at.%) are investigated by the X-ray diffraction, photoluminescence, and thermoluminescence methods. Dependences of the luminescence characteristics, as well as crystal lattice parameters and distances between the Ce<sup>3+</sup> and Mg<sup>2+</sup> ions, on the Ga, Ce, and Mg concentration are studied. Mechanisms of the processes, resulting in the photoluminescence optical and thermal quenching and acceleration of decay kinetics, and the influence of the crystal composition on these processes are discussed. The role of close {Ce<sup>3+</sup> - Mg<sup>2+</sup><sub>Ga</sub>} pairs in these processes is considered. At <em>T</em> > 400 K, the luminescence thermal quenching is caused by the crossover process, while in the 200–350 K temperature range, by the electron transfer from the 5d<sub>1</sub> excited state of Ce<sup>3+</sup> to nearby defect levels (electron traps) located between the 5d<sub>1</sub> level and the conduction band. The latter process results also in the appearance of thermally stimulated luminescence, and its efficiency depends on the Ga<sup>3+</sup> content and concentration of intrinsic defects. The optimum concentrations of Ga<sup>3+</sup> and Mg<sup>2+</sup> ions in the investigated crystals are determined.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120945"},"PeriodicalIF":3.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stable random laser of perovskite quantum dots based on SiO2-QDs-SiO2 composite nanostructure","authors":"Lihua Ye, Shaoqiang Hong, Chunguang Lu, Qing Zhao","doi":"10.1016/j.jlumin.2024.120946","DOIUrl":"10.1016/j.jlumin.2024.120946","url":null,"abstract":"<div><div>In recent years, metal halide perovskite has gradually become a hotspot in the field of optoelectronics. However, the inherent instability of CsPbX<sub>3</sub> quantum dots (QDs) seriously affects the amplified spontaneous emission (ASE) or lasing performance. Herein, the highly stable CsPbBr<sub>3</sub> random laser is realized in SiO<sub>2</sub>-QDs-SiO<sub>2</sub> (SQS) composite nanostructure doped with Ag nanoislands. The strong scattering generated by SQS composite nanostructure and the localized surface plasmon resonance (LSPR) of metal silver nanoislands provide optical feedback for the formation of random laser. Then a coherent random laser with low threshold (∼2.2 mJ/cm<sup>2</sup>) is obtained. SiO<sub>2</sub> microspheres anchor QDs to avoid photoinduced regeneration and fluorescence quenching caused by QDs clusters. The inner QDs of SQS are effectively protected from water erosion, thus resulting that the samples have higher water resistance. The luminescence intensity still maintains 70 % of the original intensity after 40 days with the addition of pure water. Our research provides an effective method for improving the water stability of perovskite QDs. The highly stable random laser based on perovskite quantum dot film has a wide application prospect in integrated optoelectronics, display imaging and sensing measurement.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"277 ","pages":"Article 120946"},"PeriodicalIF":3.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}