Nanoscale Research Letters
·
2019
·Vol. 14
·期 1
·1-10
·
IF 3.159
Fang Long,Chen Haitao,Yuan Xiaoming,Huang Han,Chen Gen,Li Lin,Ding Junnan,He Jun,Tao Shaohua
Bottom-up epitaxy has been widely applied for transition metal dichalcogenides (TMDCs) growth. However, this method usually leads to a high density of defects in the crystal, which limits its optoelectronic performance. Here, we show the effect of growth temperature on the defect formation, optical performance, and crystal stability in monolayer WSe 2 via a combination of Raman and photoluminescence (PL) spectroscopy study. We found that the defect formation and distribution in monolayer WSe 2 are closely related to the growth temperature. These defect density and distribution can be controlled by adjusting the growth temperature. Aging experiments directly demonstrate that these defects are an active center for the decomposition process. Instead, monolayer WSe 2 grown under optimal conditions shows a strong and uniform emission dominated by neutral exciton at room temperature. The results provide an effective approach to optimize TMDCs growth.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2024
·
IF 5.7
Mingjun Zhao,Panting Wang,Chongyun Shao,Weichang Li,Danping Chen,Wei Chen
Novel transparent luminescent glass ceramics with the ability to generate the line emission of Eu2+ ions were successfully prepared. First, Eu2+-doped barium–aluminum–borate oxyfluoride glasses were prepared by high-temperature melting in a reducing atmosphere, and then transparent glass ceramics were obtained by crystallization heat treatment. Fluorescence spectroscopy showed that Eu2+ exhibited only broadband luminescence (FWHM ≈ 136 nm) of the 4f65d1 → 4f7 transition in the glasses. However, after heat treatment, a 359 nm line emission (FWHM ≈ 2.8 nm) from the 4f7 → 4f7 transition of Eu2+ appeared in the glass ceramics. To explore the mechanism of transformation of the optical transition of Eu2+ from 4f65d1 → 4f7 to 4f7 → 4f7, the glasses and glass ceramics were analyzed by fluorescence spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy measurements. The results showed that the alteration in the optical transition of Eu2+ was a result of the Eu2+ ions entering the Ba2+ sites with weak crystal field strength in BaAlBO3F2 (BABF) crystals from the strong crystal field strength glass phase.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Catalysts
·
2020
·Vol. 10
·期 8
·833
·
IF 3.52
Fu-Ran Zou,Sai-Nan Wang,Fang-Fang Wang,Dan Liu,Ying Li
Tunable photoluminescent-functionalized carbon quantum dots CQDs@Ln (TFA)3(Ln = Eu, Tb; TFA: trifluoroacetylacetone) were designed and synthesized by introducing lanthanide complexes into the modified CQDs surface through the carboxyl group. The as-prepared CQDs@Ln (TFA)3emit strong blue–green light with the peak at 435 nm and simultaneously show the characteristic emission of Ln3+under irradiation of 365 nm light in aqueous solution. Moreover, these functionalized CQDs exhibit excellent photoluminescence properties. In addition, a white luminescent solution CQDs@Eu/Tb (TFA)3was obtained by adjusting the ratio of Eu3+/Tb3+and the excitation wavelengths. Moreover, CQDs@Tb (TFA)3can be utilized as a fluorescent probe for the sensitive and selective detection of MnO4−without interference from other ions in aqueous solution. These results provide the meaningful data for the multicomponent assembly and the photoluminescent-functionalized materials based on the modified CQDs and lanthanide, which can be expected to have potential application in photocatalytic or sensors.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2022
·Vol. 156
·期 23
·
IF 4.304
Pu Lei,Gu Yarong,Meng Qian,Pang Qi,Lu Aijiang,Zhao Lijuan
Zero-dimensional (0D) all-inorganic cesium lead halide perovskites, particularly Cs 4 PbBr 6 , have been attracting wide attention due to their excellent optical properties and stability. The research also focuses on the origin of green emission from Cs 4 PbBr 6 , which has a bandgap located in the ultraviolet B (UVB) region. So far, both Cs 4 PbBr 6 without visible emission and with green emission have been successfully prepared; however, the origin of green emission remains controversial. Photocurrent response is one of the effective approaches to explore how the photo-excited carriers influence the photo-physical properties of materials. In our study, Cs 4 PbBr 6 particles without visible emission and with green emission were synthesized and their photocurrent response was investigated. The former showed a positive photocurrent response, while the latter showed a negative photocurrent response. The negative response was believed to be due to a built-in electric field constructed by the charged excitons in green-emissive Cs 4 PbBr 6 . From our calculations, numerous vacancies of Br are easier to appear in green-emissive Cs 4 PbBr 6 lattices, which could combine the neutral excitons to form charged excitons. This work may contribute to the explanation of the origin of green emission of Cs 4 PbBr 6 to some extent.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Materials Au
·
2022
·
IF 0
Shunqi Lai,Ming Zhao,Yifei Zhao,Maxim S. Molokeev,Zhiguo Xia
Regulation of Eu2+ dopants in different cation sites of solid-state materials is of great significance for designing multicolor phosphors for light-emitting diodes (LEDs). Herein, we report the selective occupation of Eu2+ for multiple cationic sites in KSrScSi2O7, and the tunable photoluminescence from blue to cyan is realized through Eu2+ doping concentration-dependent crystal-site engineering. Eu2+ preferably occupies the K and Sr sites in KSrScSi2O7 at a low doping concentration, resulting in a 440 nm blue emission. As the Eu2+ concentration increases, a new Eu2+ substitution pathway is triggered, that is, Eu2+ enters the Sc site, leading to the red-shifted emission spectra from 440 to 485 nm. The doping mechanism and photoluminescence properties are corroborated by structural analysis, optical spectroscopy study, and density functional theory calculations. The optical properties of the as-fabricated white LEDs are studied, which demonstrates that these phosphors can be applied to full-spectrum phosphor-converted LEDs. This study provides a new design strategy to guide the development of multicolor Eu2+-doped oxide phosphors for lighting applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
CHEMISTRY OF MATERIALS
·
2021
·
IF 9.811
Jiyou Zhong,Chaojie Li,Weiren Zhao,Shihai You,Jakoah Brgoch
Near-infrared (NIR) phosphor-converted light-emitting diode (pc-LED) technology has attracted considerable interest as a next-generation light source for emerging NIR spectroscopic applications. However, discovering efficient broadband NIR phosphors necessary to access the desired long-wavelength (λem ≥ 800 nm) energy window remains a challenge. Here, a new phosphate phosphor, KGaP2O7:Cr3+, emerged from a fundamental study of the AMP2O7 (A = Li, Na, K; M = Al, Ga, Sc, In) family. This material combines all of the requisite properties for the efficient generation of NIR photons, including limited defect formation, minimal electron–phonon coupling, a subtle octahedral site distortion, and well-separated transition metal substitution sites. Photoluminescence spectroscopy indicates that this material emits from 700 to 1100 nm (λmax = 815 nm) with a full width at half-maximum (fwhm) of 127 nm or 1874 cm–1. Exciting the material with a blue LED reveals a quantum yield of 74.4% with an absorption efficiency of 44.8%, resulting in an excellent external quantum efficiency as high as 33.3% from the as-prepared sample. A prototype NIR pc-LED device generated an output power of 473.8 mW and a high photoelectric conversion efficiency (10.7% under 500 mA), demonstrating the potential of applying this phosphor in blue LED-based NIR spectroscopy.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Zhuo Wang,Jiaming Song,Xin Zhao,Guoshuai Ban,Yuting Li,Juanjuan Yang,Chenzheng Ye,Feng Teng,Peng Hu,Haibo Fan
Transition metal phosphorus trichalcogenides (MPX 3 ), as a group of layered van der Waals materials with wide tunable bandgaps, high carrier mobility and good light absorption, are potential candidates for the preparation of high-performance broad-spectrum photoelectrochemical photodetectors (PEC PDs). MnPSe 3 , a p-type semiconducting material in the MPX 3 family, was exfoliated into nanosheets using liquid-phase exfoliation, and then applied in the PEC PDs. The MnPSe 3 -based PEC PDs were thoroughly investigated in a three-electrode system and demonstrated self-powered photoelectric performance across a broad spectral range of 400–800 nm. Specifically, under 400 nm illumination, the photodetector showed the optimal performance with a photocurrent density of 9.72 μA/cm 2 , responsivity of 85.55 μA/W, response times of 10/15 ms and fine cyclic stability under the biased condition. In addition, effects of different stripping agents, bias voltages, wavelengths and optical powers on the device performance were compared. These findings suggest that MnPSe 3 is a highly promising material in applications of high-performance self-powered PEC PDs.
研究领域:
材料科学
·
光电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 103
·期 12
·6922-6931
·
IF 3.502
Puxian Xiong,Chibin Zheng,Mingying Peng,Zhihao Zhou,Feifei Xu,Kexin Qin,Yiyu Hong,Zhijun Ma
Till now, many doped persistent luminescence (PersL) phosphors have been investigated and found various applications in such as bioimaging, photocatalysis and information storage, but introducing PersL emitters into a proper host is mostly complex. In this research, a self-activated PersL phosphor Ba 2 Zr 2 Si 3 O 12 (BZSO) is prepared by solid state reaction. By adding NH 4 Cl, the self-activated PersL intensity is evidently enhanced. The trap depths and concentrations are examined by thermoluminescence spectra. Meanwhile, Bi 3+ ions are introduced into BZSO and show wide band photoluminescence (PL) from 300 to 600 nm. Moreover, the PL of Bi 3+ is tunable under excitation by 265-350 nm lights. Furthermore, as a proof-of-concept design, we designed a patterned quick response (QR) code based on the self-activated PersL of BZSO, and the information of “South China University of Technology (SCUT)” can be read out by the code scanning technology. Bi 3+ -doped BZSO phosphors are suggested to provide potential applications in information storage by its self-activated PersL, and to excite researchers to study the tunable PL in Bi 3+ -doped phosphor.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ECS Journal of Solid State Science and Technology
·
2018
·Vol. 7
·期 12
·R215
·
IF 1.808
Quan Dong,Fengli Yang,Jun Cui,Hong Ming,Fu Du,Jiaqing Peng,Yabin Tian,Shaohua Yang,Xinyu Ye
A series of γ-AlON: Ce3+, Mn2+ phosphors were prepared via a high-temperature solid-state reaction. The phase formation and morphology, photoluminescence excitation and emission spectra, absorption spectra, lifetime, and thermal stability were investigated in detail. The γ-AlON: Ce3+, Mn2+ phosphor showed two emission bands under 285 nm excitation. The first broad band at 400 nm was attributed to Ce3+ ion emission, and the narrow band found at 517 nm was assigned to the Mn2+ ions. The critical distance of energy transfer from Ce3+ to Mn2+ has been calculated according to the concentration quenching method. The mechanism of energy transfer from Ce3+ to Mn2+ was of the resonance type and occurred via a dipole − dipole interaction. After doping Ce3+ in the γ-AlON matrix, the absorption, internal quantum, and external quantum efficiencies of γ-AlON: Ce3+, Mn2+ can be increased to 68.8%, 60.9%, and 41.9%, respectively. Furthermore, γ-AlON: Ce3+, Mn2+ exhibited superior thermal stability, with the emission intensity measured at 150°C maintaining 99% of the maximum emission intensity.
研究领域:
材料科学
·
光学
·
固体物理
✓ 已验证
DOI
高影响因子
Materials Today Physics
·
2024
·
IF 10
Daiyuan Liu,Ru Zhao,Chao Wang,Zhichao Liu,Jian Zhang,Yuan Wang,Xue Yu,Jianbei Qiu,Xuhui Xu,Yichun Liu
High-quality phosphors with color tunability are urgently needed for the full-spectrum white light-emitting diodes (WLEDs) with healthy and comfortable lighting like the solar spectrum. Here, a Sr 2 Ga 2 SiO 7 : Eu 2+ phosphor with tunable luminescence color is reported, achieving a luminescence tuning from maize-yellow to yellow by changing the Eu 2+ ion concentration. Importantly, the quantum efficiency of BaSrGa 2 SiO 7 : 1.0 % Eu 2+ is as high as 85.7 % compared with 49.1 % of Sr 2 Ga 2 SiO 7 : 5.0%Eu 2+ , and the emission intensity of BaSrGa 2 SiO 7 : 1.0 % Eu 2+ retains 92 % of the room temperature (RT) emission intensity at 473 K by Ba 2+ substitution. Furthermore, the increase of Ba 2+ ion concentration also makes the phosphor achieve tunability from yellow to green. The as-prepared full-spectrum WLEDs exhibits a continuity spectrum like solar spectrum with an extremely high color rendering index of 93.5 and low correlated color temperature of 4562 K. This work provides new insights into the exploration of new phosphors for high-performance full-spectrum WLEDs devices.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2024
·
IF 3.2
Pengju Xia,Wanyuan Li,Kaiting Wu,Yifeng Lei,Wubin Dai
In the process of studying newfangled phosphor-converted white-light-emitting diodes (pc-wLEDs), some basic and important objectives of phosphor, i.e., high chemical/thermal stability, color rendering index (CRI), and low correlated color temperature (CCT), should pass muster simultaneously. Herein, for the first time, a series of photoluminescence (PL) color-tunable single-phase Ca3Y(GaO)3(BO3)4: Dy3+/Sm3+/La3+ (CYGB: Dy/Sm/La) phosphors with good dispersivity, crystallinity, and size uniformity have been designed and synthesized via a facile solid-state reaction method. Structurally, based on XRD and Rietveld refinements, the tendentious occupations of Dy/Sm/La on the Y3+ site with a 9-coordinated number (CN) over other cationic sites are in line with the facts that the ionic radius and charge difference of Dy/Sm/La are much closer to Y3+ in 9-CN than Y3+ in 7-CN and Ca2+ in both 9- and 7-CN. Spectrally, thanks to the “cool” white PL from 4f–4f transitions of Dy and red-emitting from Sm, polychromatic PL including “warm” white light with high efficiency could be realized in CYGB: Dy/Sm via the regulation of doping content and energy transfer (ET). Intriguingly, the “abnormal” phenomena of zero-thermal-quenching in the range from room temperature (RT) to 573 K were observed, probably owing to the synergistic effects of electron–phonon coupling, ET, and structural defects. Moreover, by tridoping La3+ to legitimately adjust the site environments, the PL of both Dy/Sm could be further tuned because they all include hypersensitive transitions that are closely related to the crystal field environment. Finally, as a proof-of-concept fabrication, the pc-wLED assembled by a combination of the composition-optimized CYGB: Dy/Sm/La and an n-UV LED chip via remote “capping” packaging shows attractive performances, indicating its potential as an efficient phosphor for n-UV wLEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Nanoscale Research Letters
·
2018
·Vol. 13
·期 1
·1-8
·
IF 3.125
Segovia Rubén,Qu Geyang,Peng Miao,Sun Xiudong,Shi Hongyan,Gao Bo
Self-assembled organic-inorganic CH 3 NH 3 PbI 3 perovskite microwires (MWs) upon humidity exposure along several weeks were investigated by photoluminescence (PL) spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). We show that, in addition to the common perovskite decomposition into PbI 2 and the formation of a hydrated phase, humidity induced a gradual PL redshift at the initial weeks that is stabilized for longer exposure (~ 21 nm over the degradation process) and an intensity enhancement. Original perovskite Raman band and XRD reflections slightly shifted upon humidity, indicating defects formation and structure distortion of the MWs crystal lattice. By correlating the PL, Raman, and XRD results, it is believed that the redshift of the MWs PL emission was originated from the structural disorder caused by the incorporation of H 2 O molecules in the crystal lattice and radiative recombination through moisture-induced subgap trap states. Our study provides insights into the optical and structural response of organic-inorganic perovskite materials upon humidity exposure.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）