Nanomaterials
·
2020
·Vol. 10
·期 7
·1249
·
IF 4.324
Jun Xiao,Cong Wang,Xin Min,Xiaowen Wu,Yangai Liu,Zhaohui Huang,Minghao Fang
Advances in solid-state white-light-emitting diodes (WLEDs) necessitate the urgent development of highly efficient single-phase phosphors with tunable photoluminescence properties. Herein, the Tm3+, Dy3+, and Sm3+ions are incorporated into the orthorhombic NaGdTiO4(NGT) phosphors, resulting in phosphors that fulfill the aforementioned requirement. The emission spectrum of Tm3+ions overlaps well with the adsorption spectra of both Dy3+and Sm3+ions. Under the excitation at 358 nm, the single-phase NaGdTiO4: Tm3+, Dy3+, Sm3+phosphor exhibits tunable emission peaks in the blue, yellow, and red regions simultaneously, resulting in an intense white-light emission. The coexisting energy transfer behaviors from Tm3+to Dy3+and Sm3+ions and the energy transfer from Dy3+to Sm3+ions are demonstrated to be responsible for this phenomenon. The phosphors with multiple energy transfers enable the development of single-phase white-light-emitting phosphors for phosphor-converted WLEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 30
·9203-9210
·
IF 6.641
Y. Y. Zhou,E. H. Song,M. G. Brik,Y. J. Wang,T. Hu,Z. G. Xia,Q. Y. Zhang
Mn4+-doped fluoride red-emitting phosphors have been developed for backlighting white light-emitting diodes (WLEDs). However, the long fluorescence lifetime (τ > 5 ms) leads to the image-retention phenomenon for the human eye when Mn4+ is doped into equivalent X sites in A2XF6 (A = Na, K, Rb, Cs; X = Si, Ge, Ti, Zr). Herein, we report on novel red-emitting A2NaScF6:Mn4+ (A = K, Rb, Cs) (ANSF) phosphors with short fluorescence lifetimes (τ < 4 ms) and characteristic zero phonon line (ZPL) emission, which can be realized via non-equivalent doping of Mn4+ into Sc3+ sites. Density functional theory (DFT) calculations verified the formation of a slightly distorted environment of Mn4+ and an Na+ vacancy to balance the charge with Mn4+ non-equivalent doping. The WLED backlight using ANSF as a red-light component can reach a wide color gamut above 105% of the National Television Standards Committee (NTSC) standard, and the image-retention on the backlighted screen can be effectively avoided compared to the backlight obtained using commercial K2SiF6:Mn4+. Such a Mn4+ non-equivalent doping strategy opens a new perspective for the modification of local symmetry and enhancement of the luminescence properties of Mn4+-doped red-emitting fluoride phosphors.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL RESEARCH
·
2012
·
IF 0.633
Yan Gao,Jian Song,Wei Wang
Four novel azobenzene derivatives, 4,4'-bis(CH2SAr)azobenzene (Ar = different heterocyclic units), have been prepared and characterised by IR, 1H NMR, 13C NMR, MS and elemental analysis. Their complexation properties to different heavy and transition metal ions have been studied by UV and fluorescence spectra. The compound 4,4'-bis(4,6-dimethyl-pyrimidine-2-ylmethylthio)azobenzene shows selective recognition of Hg2+.
研究领域:
化学
·
分析化学
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材料科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 41
·14548-14558
·
IF 7.059
Zhihao Wang,Qinghong Meng,Chunyun Wang,Dianyuan Fan,Yu Wang
Phosphor-converted white light-emitting diodes (pc-WLEDs) integrated with deep UV chips and single-component white light-emitting phosphors have attracted widespread research interest recently. (Y,Tb,Eu)NbO4 nanophosphors with full-color emission properties were achieved in this work by a facile calcination-assisted hydrothermal method, and the elaborately designed white light-emitting (Y0.988Tb0.010Eu0.002)NbO4 phosphor was successfully applied to a 275 nm chip excited pc-WLED with a relatively low correlated color temperature (CCT) of 5517 K and a high color-rendering index (CRI) of 86.7. Through a comprehensive characterization by XRD, elemental analysis, FE-SEM, TEM, TG, FT-IR, UV-vis, and optical spectroscopy, the YNbO4 nanophosphor with optimal PL properties was evidenced to be obtainable through calcining the hydrothermally crystallized precursor at 1000 °C. The quenching concentrations of Tb3+ and Eu3+ in YNbO4 were determined to be ∼4 and 5 at%, respectively, and the efficiency of the NbO43− → Tb3+ energy transfer was calculated to be ∼47.93%. Upon excitation at 260 nm, the ternary (Y,Tb,Eu)NbO4 phosphor simultaneously displays blue NbO43−, green Tb3+, and red Eu3+ emissions. Benefiting from the NbO43− → Tb3+ → Eu3+ energy transfer, full color emission was achieved via adjusting the Tb3+ and Eu3+ concentrations in (Y,Tb,Eu)NbO4. The white light-emitting (Y0.988Tb0.010Eu0.002)NbO4 phosphor with color coordinates of (0.336, 0.334) can maintain its emission color and ∼67% of its overall emission intensity at 150 °C, indicating that the phosphor is highly promising for application in deep UV chip-based pc-WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 31
·9496-9503
·
IF 6.641
Dong Ding,Henan Li,Huizhen Yao,Lai Liu,Bingbing Tian,Chenliang Su,Ye Wang,Yumeng Shi
With intense interest in lead halide perovskites for flexible optoelectronic applications, shape-controlled preparation of fibrous perovskites with high stress tolerance is desirable. We report a template synthesis method for obtaining fibrous perovskite materials, by using the capillary effect of a precursor solution. Fibrous yarn bundles, which are highly flexible and can be knitted into various patterns, are used as a template to form MAPbI3 with controllable dimensionality and morphology. On the basis of this, we further design and successfully obtain a “quasi-spring” like network based flexible photodetector. The device exhibits impressive photoelectric characteristics, that is, an ON/OFF ratio of ∼4.5 × 104, a fast photo-response speed (trise ∼ 4 ms and tdecay ∼ 10 ms at an illumination density of 80 mW cm−2), and a detectivity of 2.2 × 1011 Jones (at an illumination density of 10 μW cm−2). Furthermore, the device exhibits a minute photocurrent attenuation after 200 bending cycles, and is able to work stably even in a twisted state at 180°. This work provides a method for the controllable growth of perovskite materials, which will yield promising opportunities for constructing integrated crooked and different dimensional perovskites and optoelectronic systems.
研究领域:
材料科学
·
光电化学
·
纳米技术
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Shuang Shu,Yu Wang,Yuee Ke,Bin Deng,Rixin Liu,Qinyang Song,Jianxu Wang,Ruijin Yu
Novel orange-red-emitting tantalate NaCaTiTaO 6 (NCTT): x Sm 3+ ( x = 0.005–0.25) phosphors are synthesized via a solid-state reaction technique at 1300 °C. The phosphors exhibit an orthorhombic perovskite structure with a space group of Pnma (No. 62). At 407 nm excitation, the phosphors show the strongest emission peak at 647 nm belonging to the 4 G 5/2 → 6 H 9/2 transition. The optimal Sm 3+ concentration is 0.05 mol, and concentration quenching is caused by dipole–dipole interaction. The NCTT:0.05Sm 3+ phosphor exhibit a broad bandgap of 3.44 eV and a high color purity of 99.9%. At 420 K, the decrease in intensity is only 10% of the initial value at 300 K for NCTT:0.05Sm 3+ phosphor but 15% for Y 3 Al 5 O 12 :Ce 3+ phosphor. Consequently, the fabricated white light-emitting diodes exhibit a high rendering index value of 89, a good correlated color temperature of 5257 K, and CIE coordinates of (0.339, 0.364). Hence, the Sm 3+ -doped orange-red-emitting NCTT phosphors have potential applications for w-LEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2022
·Vol. 10
·期 8
·2102201
·
IF 10.05
Jiexin Li,Zongtao Li,Jiayong Qiu,Jiasheng Li
Quantum dots (QDs) exhibit remarkable photoelectric performance. However, the conversion efficiency and thermal performance of QD converters so far is not satisfactory for high-power solid-state light (SSL) applications owing to the serious reabsorption loss of QDs and the poor thermal diffusion of polymer materials. Here, an efficient QD converter based on an anodic aluminum membrane (AAM), with high light enhancement and thermal diffusion, is introduced for high-power SSL applications. Nanoporous AAMs are utilized as templates for confining the QD deposition into the nanowire (NW) shape by incorporating inkjet printing and vacuum-deposition methods, forming vertical QD NW arrays. Compared with conventional converters, QD-AAM yields nearly twofold photoluminescence intensity. Three-dimensional finite-difference (FDTD) simulations attribute the fluorescence-enhancement mechanism to the enhancement of QD conversions and boosting of the waveguide effect in QD-AAM. Furthermore, QD-AAM exhibits excellent thermal diffusion performance under high-power excitation, owing to the inner heat conduction path in the AAM framework. This study provides a practical and efficient strategy to comprehensively enhance the optical and thermal performance of QD converters for high-power SSL applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2020
·Vol. 49
·期 38
·13226-13232
·
IF 4.174
Yajun Jia,Yuexiao Pan,Jiawen Zhu,Xi'an Chen,Aiyin Wang,Hongzhou Lian,Jun Lin
Red emitting phosphors of Mn4+ doped fluorides are in high demand because the high color purities of phosphors make them potentially useful white light-emitting diodes (WLEDs) as backlights of electronic devices. We herein report an efficient red emitting phosphor KRbGeF6 : Mn4+ (KRGF : Mn) that was prepared by an in situ one-pot ion-exchange method at room temperature without organic solvents or HF. Homogenous mixtures of the starting materials with a stoichiometric KRGF : Mn ratio were partly dissolved in various acid solutions, and [MnF6]2− and [GeF6]2− successively underwent ion exchange under stirring. More importantly, in situ recrystallization of KRGF : Mn occurred simultaneously in solution with water as a solvent. Evidently, the formation of stable KRGF : Mn crystals propels the processes of dissolution and ion exchange. We also investigated the effect of inorganic acids on the resultant phases and photoluminescence properties of KRGF : Mn. The red phosphor KRGF : Mn prepared in HCl solution shows the highest luminescence intensity with an yield of 80%.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2020
·Vol. 22
·期 8
·4453-4463
·
IF 3.43
Bo Yan,Chun Du,Zhaoyong Lin,Guowei Yang
Amorphous carbon nitrogen (a-CN) has attracted a lot of attention due to its unique properties, different from those of its crystal form. Here, we demonstrate a near-infrared (NIR) photothermal conversion assisted photocatalytic hydrogen evolution from a-CN with nitrogen vacancies (a-CNN) nanosheets. Experiments suggest that sp2 hybridized CC structures can be created in a-CNN. These structures, just like small islands, disperse on a-CNN, leading to fluorescence quenching and a superior vis-NIR light absorption. Meanwhile, these structures, like “hot islands”, can generate a stronger NIR photothermal conversion. A series of in situ characterization techniques are developed to clarify the detailed mechanism of photothermal conversion assisted photocatalytic hydrogen evolution. It is found that photothermal conversion can not only accelerate the drift velocity of the photo-induced carrier, but also increase the carrier concentration, which finally promotes the photocatalytic hydrogen evolution. Due to photothermal conversion assistance, the hydrogen production rate of a-CNN nanosheets is promoted to 3.1 mmol g−1 h−1 compared to 0.71 mmol g−1 h−1 for a-CN, in which the NIR photothermal conversion is proven to contribute a 16% promotion to the hydrogen production. These findings suggest that creating an NIR photothermal conversion of photocatalysts by constructing “hot islands” can greatly promote photocatalytic hydrogen production.
研究领域:
材料科学
·
能源化学
·
光催化
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Lei Wang,Ruipeng Hou,Tengfei Huang
The upconversion (UC) emission behavior occurs usually in rare-earth doped compounds but rarely in pure semiconductors. Herein, the UC emission behavior of WO 3 was investigated. The oxygen-vacancy-rich WO 3 nanosheets were rapidly synthesized by high-power laser irradiation. The red UC emission peaked at ∼1.75 eV is observed in the synthesized WO 3 nanosheets under continuous 980 nm or 1940 nm laser excitation. The UC emission stems from the abundant oxygen-deficient levels and belongs to a multiphoton absorption behavior. Meanwhile, the laser-power-dependent UC behavior could be attributed to the transformation of different oxygen defect states. On this basis, a variable output color phosphor based on Er-Yb co-doped WO 3 [WO 3 :(Er, Yb)] was developed. The WO 3 :(Er, Yb) phosphor can change the UC color from green to red with increasing the 980-nm laser power. Moreover, the upconversion behavior of WO 3 can be utilized to assist WS 2 photocatalysis. This work develops a pure semiconductor with an interesting UC emission and clarifies the UC mechanism.
研究领域:
材料科学
·
光学
·
光催化
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Hezhen Wu,Huidong Tang,Qing Hu,Yanqiao Xu,Wentao Li,Xiaojun Zhang,Feng Jiang,Guo Feng,LianJun Wang,Wan Jiang
Recently, vacancy-ordered double perovskite phosphors have garnered significant attention due to their high quantum efficiency, elevated carrier mobility, and favorable fluorescence properties. Vacancy ordered double perovskite phosphors has poor fluorescence properties due to the high number of vacancies. The fluorescence characteristics and stability can be enhanced through strategic ion doping. This study synthesized Zr 4+ ion-doped Cs 2 SnCl 6 : 5 %Te using hydrochloric acid-assisted precipitation method. The inclusion of Zr 4+ ions in proper proportions facilitated Jahn-Teller structural distortion in Te 4+ , thereby enhancing the generation of bright yellow-green emission. The photoluminescence quantum yield (PLQY) achieved a peak of 70.9 % at a Zr 4+ ion doping level of 15 %. Furthermore, a water stability test was conducted on the phosphors. At 15 % doping with Zr ions, The Cs 2 Zr 0.15 Sn 0.8 Cl 6 : 5 %Te phosphors demonstrated a remarkable stability, which maintained 100 % of its initial fluorescence intensity after immersion in water for 14 h, proving the excellent stability of the phosphors against water exposure. A white light-emitting diode (WLED) with color coordinates of (0.3486, 0.364), a correlated color temperature of 4915 K, and a color-rendering index (Ra) of 86 was prepared using Cs 2 Zr 0.15 Sn 0.8 Cl 6 : 5 %Te phosphor. This development offers a novel and eco-friendly approach to solid state lighting.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
BIOCONJUGATE CHEMISTRY
·
2018
·
IF 4.485
Zheng Ruan,Wei Miao,Pan Yuan,Liu Le,Lijuan Jiao,Erhong Hao,Lifeng Yan
NIR photosensitizer is attractive for photodynamic therapy (PDT). Low-power light irradiation and imaging-guided PDT makes it possible to increase tissue penetration depth. The pyrrole-substituted iodinated BODIPY (BDPI) molecule was designed and synthesized, and it possesses an intense NIR absorption and emission band, and exhibits a high singlet oxygen quantum yield (ΦΔ = 0.80) which leads remarkable cytotoxicity upon low power illumination (IC50 = 0.60 μg/mL, 6.1 mW/cm2). After being encapsulated with biocompatibility polypeptide PEG–PLys, polymeric micelles nanoparticles (PBDPI NPs) was obtained that are water-dispersed and passively tumor-targetable. Such enhanced accumulation in tumor area makes it easily traced in vivo due to its NIR fluorescence. In addition, such nanoparticles offer an unprecedented photodynamic therapeutic effect by using a low-power irradiation light, which makes it possible to kill cancer cells in deep tissue efficiently.
研究领域:
生物医学工程
·
肿瘤学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）