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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xiang J., Zheng J., Zhou Z., Suo H., Zhao X., Zhou X., Zhang N., Molokeev M. S., Guo C.
Заглавие : Enhancement of red emission and site analysis in Eu2+ doped new-type structure Ba3CaK(PO4)3 for plant growth white LEDs
Место публикации : Chem. Eng. J. - 2019. - Vol. 356. - P.236-244. - ISSN 13858947 (ISSN) , DOI 10.1016/j.cej.2018.09.036
Примечания : Cited References: 42. - This work was supported by National Natural Science Foundation of China (No. 11704312 , 51672215 , 11274251 ), Research Fund for the Doctoral Program of Higher Education of China (RFDP) (No. 20136101110017) and by RFBR (17-52-53031).
Ключевые слова (''Своб.индексиров.''): phosphor--ba3cak(po4)3--sites-dependent photoluminescence--plant growth--white leds
Аннотация: A novel compound Ba3CaK(PO4)3 (BCKP) with new-type structure was synthesized and its structure was determined by X-ray diffraction Rietveld refinement, in which crystal structure consists of Ba1O9, Ba2O12, Ba3O9, CaO8 and KO10 polyhedra, that's five cationic sites. As a phosphor host, Eu2+ doped BCKP emits cold white light with about 90% quantum efficiency (QE) through entering different cationic sites. Based on the results of refinement, three Eu2+ luminescence centers in sites Ca, Ba2 and K were clearly assigned in Eu2+ solely doped BCKP by the time-resolved emission spectra (TRES), Van Uitert equation, but the emissions of Eu2+ at Ba1 and Ba3 sites are not easy to be determined for the same coordination number (CN). According to their different spatial distribution of the coordinated atoms, the first-principles calculation was used to compute the d orbital splitting energy of Eu2+ ions in Ba1 and Ba3 sites to accurately distinguish the ambiguous luminescence centers. In order to meet the requirement of plant growth spectra, Mn2+ was introduced into BCKP: Eu2+ to enhance the red component of spectra, which not only perfectly match with the absorption spectra of carotenoid and chlorophyll-b, but also LEDs fabricated through combining 365 nm near ultraviolet (n-UV) chip with BCKP: Eu2+, Mn2+ phosphor exhibit excellent parameters including high color rendering index (Ra) (92), excellent correlated color temperature (CCT) (4486 K) and outstanding QE up to 65%. Results confirmed that BCKP: Eu2+/Mn2+ phosphor with great potential applications in white LEDs and plant growth.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhao, Ming, Liao, Hongxu, Molokeev M. S., Zhou, Yayun, Zhang, Qinyuan, Liu, Quanlin, Xia, Zhiguo
Заглавие : Emerging ultra-narrow-band cyan-emitting phosphor for white LEDs with enhanced color rendition
Место публикации : Light: Sci. Appl. - 2019. - Vol. 8. - Ст.38. - ISSN 2047-7538, DOI 10.1038/s41377-019-0148-8
Примечания : Cited References: 31. - The present work was supported by the National Natural Science Foundations of China (Grant Nos. 51722202, 51572023 and 91622125), Natural Science Foundations of Beijing (2172036), Fundamental Research Funds for the Central Universities (FRF-TP-18-002C1), and the Guangdong Provincial Science & Technology Project (No. 2018A050506004). M.S.M. is grateful for the support from the Russian Foundation for Basic Research (Grant No. 17-52-53031).
Предметные рубрики: LUMINESCENCE PROPERTIES
TEMPERATURE
ROUTE
Аннотация: Phosphor-converted white LEDs rely on combining a blue-emitting InGaN chip with yellow and red-emitting luminescent materials. The discovery of cyan-emitting (470–500 nm) phosphors is a challenge to compensate for the spectral gap and produce full-spectrum white light. Na0.5K0.5Li3SiO4:Eu2+ (NKLSO:Eu2+) phosphor was developed with impressive properties, providing cyan emission at 486 nm with a narrow full width at half maximum (FWHM) of only 20.7 nm, and good thermal stability with an integrated emission loss of only 7% at 150 °C. The ultra-narrow-band cyan emission results from the high-symmetry cation sites, leading to almost ideal cubic coordination for UCr4C4-type compounds. NKLSO:Eu2+ phosphor allows the valley between the blue and yellow emission peaks in the white LED device to be filled, and the color-rendering index can be enhanced from 86 to 95.2, suggesting great applications in full-spectrum white LEDs.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yang, Xiang, Zhang, Y.u., Zhang, Xuejie, Chen, Jian, Huang, Haisen, Wang, Dongsheng, Chai, Xirong, Xie, Gening, Molokeev M. S., Zhang, Haoran, Liu, Yingliang, Lei, Bingfu
Заглавие : Facile synthesis of the desired red phosphor Li2Ca2Mg2Si2N6:Eu2+ for high CRI white LEDs and plant growth LED device
Место публикации : J. Am. Ceram. Soc. - 2020. - Vol. 103, Is. 3. - P.1773-1781. - ISSN 0002-7820, DOI 10.1111/jace.16858. - ISSN 1551-2916(eISSN)
Примечания : Cited References: 34. - National Natural Science Foundations of China, Grant/Award Number: 21671070 and 51802101; Project GDUPS; Natural Science Foundation of Guangdong Province, Grant/Award Number: 2018A030310217; Guangzhou Science & Technology Project, Grant/Award Number: 201704030086; Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams; National Undergraduate Innovation and Entrepreneurship Training Program granted for Gening Xie, Grant/Award Number: 201910564035
Предметные рубрики: IN-GLASS
LUMINESCENCE
PERFORMANCE
EFFICIENT
EMISSION
ROUTE
Аннотация: The red emission with suitable peak wavelength and narrow band is acutely required for high color rendering index (CRI) white LEDs without at the cost of the luminous efficacy. Herein, the Li2Ca2Mg2Si2N6:Eu2+ red phosphor was prepared with facile solid‐state method using Ca3N2, Mg3N2, Si3N4, Li3N, and Eu2O3 as the safety raw materials under atmospheric pressure for the first time, which shows red emission peaking at 638 nm with full width at half maximum (FWHM) of 62 nm under blue light irradiation and becomes the desired red phosphor to realize the balance between luminous efficacy and high CRI in white LEDs. The morphology, structure, luminescence properties, thermal quenching behavior, and chromaticity stability of the Li2Ca2Mg2Si2N6:Eu2+ phosphor are investigated in detail. Concentration quenching occurs when the Eu2+ content exceeds 1.0 mol%, whereas high‐temperature photoluminescent measurements show a 32% drop from the room‐temperature efficiency at 423 K. In view of the excellent luminescence performances of Li2Ca2Mg2Si2N6:Eu2+ phosphor, a white LEDs with CRI of 91 as a proof‐of‐concept experiment was fabricated by coating the title phosphor with Y3Al5O12:Ce3+ on a blue LED chip. In addition, the potential application of the title phosphor in plant growth LED device was also demonstrated. All the results indicate that Li2Ca2Mg2Si2N6:Eu2+ is a promising red‐emitting phosphor for blue LED‐based high CRI white LEDs and plant growth lighting sources.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou, Guojun, Jiang, Xingxing, Zhao, Jing, Molokeev M. S., Lin, Zheshuai, Liu, Quanlin, Xia, Zhiguo
Заглавие : Two-dimensional-layered perovskite ALaTa2O7:Bi3+ (A = K and Na) phosphors with versatile structures and tunable photoluminescence
Место публикации : ACS Appl. Mater. Interfaces. - 2018. - Vol. 10, Is. 29. - P.24648-24655. - ISSN 1944-8244, DOI 10.1021/acsami.8b08129
Примечания : Cited References: 48. - The authors acknowledge the support from the National Natural Science Foundation of China (Nos. 51722202, 91622125, and 51572023) and the Natural Science Foundations of Beijing (2172036) and RFBR (17-52-53031).
Предметные рубрики: GENERALIZED GRADIENT APPROXIMATION
YELLOW-EMITTING PHOSPHOR
Ключевые слова (''Своб.индексиров.''): 2d-layered perovskite--bi3+ emission--ion exchange--photoluminescence tuning--white light leds
Аннотация: Topological chemical reaction methods are indispensable for fabricating new materials or optimizing their functional properties, which is particularly important for two-dimensional (2D)-layered compounds with versatile structures. Herein, we demonstrate a low-temperature (∼350 °C) ion exchange approach to prefabricate metastable phosphors ALa1–xTa2O7:xBi3+ (A = K and Na) with RbLa1–xTa2O7:xBi3+ serving as precursors. The as-prepared ALa0.98Ta2O7:0.02 Bi3+ (A = Rb, K, and Na) share the same Dion–Jacobson type 2D-layered perovskite phase, and photoluminescence analyses show that ALa0.98Ta2O7:0.02 Bi3+ (A = Rb, K, and Na) phosphors exhibit broad emission bands peaking at 540, 550, and 510 nm, respectively, which are attributed to the nonradiative transition of Bi3+ from excited state 3P1 or 3P0 to ground state 1S0. The various Bi3+ local environments at the crystallographic sites enable the different distributions of emission and excitation spectra, and the photoluminescence tuning of ALa0.98Ta2O7:0.02 Bi3+ (A = Rb, K, and Na) phosphors are realized through alkali metal ion exchange. Notably, the combination of superior trivalent bismuth emission and low-temperature ion exchange synthesis leads to a novel yellow-emitting K(La0.98Bi0.02)Ta2O7 phosphor which is successfully applied in a white LED device based on a commercially available 365 nm LED chip. Our realizable cases of this low-temperature ion exchange strategy could promote exploration into metastable phosphors with intriguing properties.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H., Wang L., Molokeev M. S., Hirosaki N., Xie R., Huang Z., Xia Z., Ten Kate O. M., Liu L., Atuchin V. V.
Заглавие : Structure evolution and photoluminescence of Lu3(Al,Mg)2(Al,Si)3O12:Ce3+ phosphors: New yellow-color converters for blue LED-driven solid state lighting
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 28. - P.6855-6863. - ISSN 20507534 (ISSN), DOI 10.1039/c6tc00966b
Примечания : Cited References: 44. - This work was partially supported by the National Natural Science Foundations of China (Grant No. 51511130035, 51272259, 61575182, 51561135015, and 51572232) and the Russian Foundation for Basic Research (Grant No. 15-52-53080). We are also grateful to financial support from the JSPS KAKENHI (No. 15K06448). H. J. thanks the China Scholarship Council (CSC) for scholarship support. V. V. A. was partially supported by the Ministry of Education and Science of the Russian Federation.
Предметные рубрики: WHITE LEDS
LUMINESCENCE PROPERTIES
EMITTING-DIODES
GARNET PHOSPHORS
SUBSTITUTION
Ce3+
PHASE
Ca
Аннотация: This paper reports the development of new phosphors using the chemical unit cosubstituting solid solution design strategy. Starting from Lu3Al5O12, the Al3+-Al3+ couple in respective octahedral and tetrahedral coordination was simultaneously substituted by a Mg2+-Si4+ pair forming the Lu3(Al2-xMgx)(Al3-xSix)O12:Ce3+ (x = 0.5-2.0) series; as a result, the CeO8 polyhedrons were compressed and the emission got red-shifted from green to yellow together with the broadening. The evolution of, the unit cell, the local structural geometry as well as the optical properties of Ce3+ in these garnet creations, in response to the gradual Mg-Si substitution for Al-Al, were studied by combined techniques of structural refinement and luminescence measurements. The new composition Lu2.97Ce0.03Mg0.5Al4Si0.5O12 was comprehensively evaluated regarding its potential application in blue LED-driven solid state white lighting: the maximum emission is at 550 nm under ?ex = 450 nm; the internal and external quantum efficiencies can reach 85% and 49%, respectively; a 1-phosphor-converted wLED lamp fabricated using the as-prepared phosphor exhibits the luminous efficacy of 105 lm W-1, the correlated color temperature of 6164 K and the color rendering index (Ra) of 75.6. The new solid solution composition series is open for further optimization to enhance the competence for commercial consideration. © 2016 The Royal Society of Chemistry.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zheng Y., Zhang H., Zhang H., Xia Z., Liu Y., Molokeev M. S., Lei B.
Заглавие : Co-substitution in Ca1−xYxAl12−xMgxO19 phosphors: local structure evolution, photoluminescence tuning and application for plant growth LEDs
Место публикации : J. Mater. Chem. C. - 2018. - Vol. 6, Is. 15. - P.4217-4224. - ISSN 20507534 (ISSN), DOI 10.1039/c8tc00165k
Примечания : Cited References: 47. - The present work was supported by the National Natural Science Foundation of China (Grant No. 21671070), the Project for Construction of High-level University in Guangdong Province, and the Teamwork Projects funded by the Guangdong Natural Science Foundation (Grant No. S2013030012842), and the Guangzhou Science & Technology Projects (No. 201704030086, 201605030005), and the reported study was funded by the RFBR according to the research project 17-52-53031. Special Funds for the Cultivation of Guangdong College Students’ Scientific and Technological Innovation (‘‘Climbing Program’’ Special Funds) were granted for Dr Yinjian Zheng.
Ключевые слова (''Своб.индексиров.''): co substitution--crystal structure transformation--high temperature solid-state reaction--lighting systems--local structure--luminescence measurements--structural refinement--tunable luminescences
Аннотация: Herein, Mn4+-activated Ca1-xYxAl12-xMgxO19 (x = 0-0.50) solid solutions were prepared using a conventional high-temperature solid-state reaction. Crystal structure transformation via chemical co-substitution of Y3+/Mg2+ for Ca2+/Al3+ was investigated in detail. The optical properties of Ca1-xYxAl12-xMgxO19 (x = 0-0.50) have been reported for the first time using a combination of techniques including structural refinement and luminescence measurements. Co-doping of Mg and Y cations within the CaAl12O19 host in a controlled manner resulted in the as-prepared samples with red/far-red ratio-tunable luminescence properties. The emission bands well-matched with the absorption band of phytochrome. Interestingly, enhanced Mn4+ luminescence can be obtained upon the addition of Mg2+ and Y3+. Unexpectedly, the quantum yields exhibit a slight change when x is in the range from 0.05 to 0.40; this indicates that these solid solutions have significant potential as lighting systems for plant growth.
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou Z., Zhang N., Chen J., Zhou X., Molokeev M. S., Guo C.
Заглавие : The Vis-NIR multicolor emitting phosphor Ba4Gd3Na3(PO4)6F2: Eu2+, Pr3+ for LED towards plant growth
Место публикации : J. Ind. Eng. Chem. - 2018. - Vol. 65. - P.411-417. - ISSN 1226086X (ISSN), DOI 10.1016/j.jiec.2018.05.014
Примечания : Cited References: 36. - This work was supported by National Natural Science Foundation of China (No. 11704312, 11274251), Research Fund for the Doctoral Program of Higher Education of China (RFDP) (No.20136101110017), Foundation of Key Laboratory of Photoelectric Technology in Shaanxi Province (15JS101).
Ключевые слова (''Своб.индексиров.''): phosphor--plant growth--leds--energy transfer
Аннотация: Photosynthesis process is the basic for plant growth, which needs energy from the light. The pigments of chlorophyll a, b and bacteriochlorophyll are responsible for the absorption of light, in which blue, red and near-infrared (NIR) light directly or indirectly promote the plant growth and enhancement of nurtiments. It is important for plant to support absorbable light, and phosphhor-converted light emitting diodes (pc-LEDs) are low-cost, energy-saving and enviromental friendly devices for plant growth. To develop a phosphor with emission covering the blue, red and NIR, a series of phosphors Ba4Gd3Na3(PO4)6F2: Eu2+, Pr3+ with blue, red and NIR multi-emitting were prepared. Their emissions not only match well with the absorption spectra of pigments in the plant, but also could be excited by near ultraviolet (n-UV) LED chip. The crystal structure of host Ba4Gd3Na3(PO4)6F2 was refined from the XRD data and three different crystallographic sites occupied by Eu2+ were determined through low temperature photoluminescence spectra. The energy transfer from Eu2+ to Pr3+ ions was also discussed in detail. Results indicated that the multi-emitting Ba4Gd3Na3(PO4)6F2: Eu2+, Pr3+ can serve as a phosphor candidate for plant growth LEDs.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gai S. J., Zhou C., Peng L., Wu M. H., Gao P. X., Su L. J., Molokeev M. S., Zhou Z., Xia M.
Заглавие : A novel Cr3+-doped stannate far red phosphor for plant lighting: structure evolution, broad-narrow spectrum tuning and application prospect
Место публикации : Mater. Today Chem. - 2022. - Vol. 26. - Ст.101107. - ISSN 24685194 (ISSN), DOI 10.1016/j.mtchem.2022.101107
Примечания : Cited References: 50. - The authors would like to gratefully acknowledge funds from the National Natural Science Foundation of China (Grant No. 51974123), the Distinguished Youth Foundation of Hunan Province (Grant No.2020JJ2018), the Key R & D projects in Hunan Province (2020WK2016, 2020SK2032, 2021SK2047, 2022NK2044), the Natural Science Foundation of Hunan Province, China (Grant No. 2021JJ40261), the Hunan High Level Talent Gathering Project (2019RS1077&2020RC5007), the Scientific Research Fund of Hunan Provincial Education Department (19C0903), the Natural Sciences Foundation of Hunan Agricultural University, China (Grant No. 19QN11), Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Resource Utilization Science Foundation (19KFXM12), Changsha Science and technology plan (KH2005114 and KH2201428), the Hunan Graduate Scientific Research Innovation Project (2022XC017) and the College Students' Innovative Training (S202110537012 and s202210537079x)
Аннотация: Chemical unit cosubstitution is an effective strategy to regulate the luminescence properties of phosphors, and it has attracted huge attention in the last few years. Following the design principles of the match of effective ion radius, atomic valence equilibrium and stoichiometric substitution, the local structure of crystal can be well customized, which is beneficial to develop high-performance luminescent materials. In this work, Mg2+-Sn4+ sites were cosubstituted by Zn2+-Ti4+ ion pairs in Mg2SnO4: Cr3+, respectively, and the emission spectra was successfully serially tuned from broad-band to narrow-band along with a unique variation trend of blue shift first and then slightly red shift. The photoluminescence excitation (PLE), photoluminescence (PL) spectra, lifetime decay, Raman spectra and electron paramagnetic resonance (EPR) were used to analyze the mechanism of luminescence tuning. Based on the manipulation of local structure, the as-observed distinct luminescence tuning can be well understood by the crystal field theory, nephelauxetic effect and changed Cr3+ capacity in this phosphor. Moreover, the adjusted narrow-band far-red emission spectra peak at 732 nm, matching the characteristic absorption of plant phytochrome PFR, has broad application prospects in the field of plant growth lighting. In addition, light-regulated dwarf potted tomato experiments were carried out to verify the application of far-red light in plant growth.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Dai X., Zou X., Zhang H., Chen W., Yang C., Molokeev M. S., Xia Z., Liu Y., Zhang X., Zheng M., Lei B.
Заглавие : Novel Cr3+-doped garnet phosphor with broadband efficient far-red emission for photochrome matching plant-lighting
Колич.характеристики :9 с
Место публикации : Adv. Opt. Mater. - 2024. - Vol. 12, Is. 11. - Ст.2302380. - ISSN 21951071 (eISSN), DOI 10.1002/adom.202302380
Примечания : Cited References: 54. - The work was supported by the National Natural Science Foundations of China (No. 12274144), the Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (No. 2023KJ122), the Key Realm R&D Program of Guangdong Province (No. 2021B0707010003), the Guangdong Provincial Science and Technology Project (No. 2022A1515010229), and the Project of GDUPS (2018) for Prof. Bingfu LEI
Аннотация: Cr3+-doped phosphors are highly recognized in various fields for their remarkable luminous efficiency and spectral flexibility, including modern agriculture and horticulture. However, the shortage of suitable Cr3+-doped phosphors for far-red LED devices has inhibited their popularization in plant lighting. Herein, an innovative Cr3+-doped phosphor Ca2YAl3Ge2O12:Cr3+ (CYAG:Cr3+), achieving a broad far-red emission at 770 nm upon 450 nm blue light excitation is designed. The optimal CYAG:Cr3+ phosphor exhibits a high internal quantum yield of 78.2% and low thermal-quenching behavior of 85%@373 K. Thus, the fabricated phosphor-converted LEDs (pc-LEDs) for plant far-red lighting have a high output power of 33.3 mW and photovoltaic conversion efficiency of 11.5% at 100 mA. The potential of CYAG:Cr3+ in plant lighting is assessed by supplementing the far-red lighting of Italian lettuce with fabricated pc-LEDs, and the biomass of Italian lettuce is significantly increased by 33%. The successful development of CYAG:Cr3+ phosphors provides a high-quality option for plant far-red light devices and further stimulates the development of new Cr3+-doped plant-lighting phosphors.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tikhomirov A. A., Molokeev M. S., Velichko V. V.
Заглавие : Photo-biological effectiveness of PAR for radish plant communities irradiated using an LED source with an adjustable spectrum
Колич.характеристики :8 с
Место публикации : Light Eng. - 2024. - Vol. 32, Is. 2. - P.70–77. - ISSN 02362945 (ISSN), DOI 10.33383/2023-063. - ISSN 25419935 (eISSN)
Примечания : Cited References: 15. - The study was carried out with financial support within the framework of State Assignment 121101300066-7 of the Ministry of Education and Science and the Strategic Academic Leadership Program "Priority-2030" for the Siberian Federal University
Аннотация: The aim of the current study was to find the most effective spectral modes of irradiation of short-season plants (for example, radish) using a fluorescent LED irradiator with a variable spectrum. The research methodology was based on the species-specific response of plants to the spectral composition of light. Photo-biological experiments were carried out to find effective spectral composition of PAR for cultivating radish communities under stable and variable irradiation modes of electrical lighting. It was shown that under stable irradiation modes, the highest productivity of economically useful radish biomass had been achieved at spectral composition with a maximum of 60 % radiation in the (600–700) nm region in a variable spectral irradiation mode. The variable spectral irradiation mode turned out to be the most effective when the spectral composition with the dominance of red rays was changed to the spectral composition with the dominance of blue rays. There were no significant differences between the best production parameters for stable and variable modes of irradiation of radish plants, which indicates the expediency of choosing the stable spectral mode of irradiation of radish plants as a short-season crop under electrical illumination. The results obtained can be used to select spectral irradiation modes for short-season plants grown under electrical lighting in northern regions and in isolated rooms in various climatic zones using "City-farm" technologies.
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