JOURNAL OF LUMINESCENCE
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2017
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IF 2.686
A. Bayat,E. Saievar-Iranizad
Blue photoluminescent WS 2 quantum dots (QDs) were synthesized using a simple top-down method from natural raw mineral tungsten disulfide via tip ultrasonication followed by centrifugation in a water-ethanol (0.7/0.3 ratio) as eco-friendly solvent. Cavitation process at a high power (300 W) led to the breaking of bulk WS 2 flakes to its quantum dots. The as synthesized WS 2 QDs showed blue photoluminescence upon UV excitation. The synthesized WS 2 QDs were analysed by UV–vis and photoluminescence spectrophotometry , transmission electron microscopy , atomic force microscopy and X-ray diffraction. According to the transmission electron microscopy images, the size of WS 2 QDs was obtained as 5 nm in average.
研究领域:
材料科学
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纳米技术
✓ 已验证
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
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IF 5.2
Zhe Xu,Lina Cao,Jingming Chan,Balaji Devakumar,Xiaoyong Huang
Highly efficient broadband blue-emitting phosphors are urgently needed for full-visible-spectrum white light-emitting diodes (WLEDs). Herein, we report a new highly luminescent garnet-type Ca 2 LuHf 2 GaAl 2 O 12 :Ce 3+ (abbreviated as: CLHGAO:Ce 3+ ) blue phosphor enabling full-visible-spectrum LED lighting. These CLHGAO:Ce 3+ phosphors doped with different Ce 3+ concentrations have been prepared by using a high-temperature solid-state reaction approach, and their phase purity, crystal structure, luminescent properties, CIE color coordinates, and quantum efficiency have been systematically studied. Importantly, CLHGAO:Ce 3+ blue phosphors show a broadband excitation spectrum in the 300–450 nm spectral range peaking around 398 nm, matching well with the emission wavelengths of commercial near-ultraviolet LED chips (380–420 nm). Upon 398 nm excitation, the optimal CLHGAO:2%Ce 3+ phosphor sample generates a bright broad blue emission band (emission peak: 472 nm; bandwidth: 84 nm) with high internal quantum efficiency of 79.2% and external quantum efficiency of 55.3%. Notably, the emission intensity of CLHGAO:2%Ce 3+ phosphor is about 1.87 times higher compared to the commercial BaMgAl 10 O 17 :Eu 2+ blue phosphor (emission peak: 451 nm; bandwidth: 53 nm). Finally, a white LED device is fabricated with a 395 nm near-UV LED chip with CLHGAO:2%Ce 3+ blue phosphor and commercial (Ba,Sr) 2 SiO 4 :Eu 2+ green phosphor as well as commercial CaAlSiN 3 :Eu 2+ red phosphor, and the device demonstrates bright warm-white emission with an ultrahigh color rendering index (Ra = 95.1, R9 = 97.8, R12 = 88.4) and low correlated color temperature of 3540 K. These results show that as-developed blue-emitting CLHGAO:Ce 3+ garnet phosphors with superior photoluminescence properties can potentially be used in phosphor-converted full-visible-spectrum WLEDs.
研究领域:
材料科学
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光学工程
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DOI
高影响因子
Journal of Materials Chemistry C
·
2021
·Vol. 9
·期 48
·17444-17450
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IF 7.393
Shuhua Tu,Min Chen,Limin Wu
Creating highly efficient and stable pure blue (≈470 nm) perovskite quantum dots (PQDs) remains a considerable challenge. Here, we report an effective synthesis strategy of ultrasmall (≈3.8 nm) blue CsPbBr3 QDs by using PbBr2 clusters as nucleation sites, which then react with Cs-oleate at relatively low temperatures. The emission wavelength of CsPbBr3 QDs ranging from 460 nm to 497 nm could be facilely tuned by the amount of Cs-oleate or reaction temperature. The optimum PL QY of the blue CsPbBr3 QDs reaches as high as above 64%. The CsPbBr3 QDs are further coated with superhydrophobic fluorinated silica and successfully applied in blue light-emitting diodes (LEDs). The nucleation-controlled growth of ultra-small blue PQDs provides a new synthesis strategy for efficient and stable blue PQDs.
研究领域:
材料科学
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光学工程
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DOI
高影响因子
Advanced Optical Materials
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2025
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IF 7.2
Wei Wang,Shizheng Zhang,Sitao Huo,Fan Cao,Sheng Wang,Qianqian Wu,Rui Li,Xuyong Yang
Indium phosphide (InP) quantum dots (QDs) have emerged as eco-friendly substitutes for cadmium (Cd)-based QDs. However, their electroluminescence (EL) performance, especially for blue ones, lags significantly behind that of the state-of-the-art Cd-based counterparts. This disparity can be attributed to the abundant defect states arising from their high surface area/volume ratio and irregular size distribution caused by high-reactivity phosphorus (P) precursor. Herein, trimethylgermanium chloride is developed into the P precursor, effectively modulating the nucleation reaction rate and drastically reducing phosphorus oxide defects. Furthermore, the epitaxial growth of the ZnS layer is successfully achieved employing zinc diethyldithiocarbamate as the precursors. This approach not only facilitates superior crystallinity in QDs at lower temperatures but also effectively suppresses electron diffusion to the shell, thereby alleviating the persistent redshift and ensuring the peak position remains within the blue emissive range. Consequently, the synthesized blue InP/ZnS QDs demonstrate a PLQY of 73% at 474 nm, empowering them to exhibit exceptional EL performance with a peak external quantum efficiency of 2.38% and a record luminance of 2693 cd cm −2 .
研究领域:
材料科学
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纳米技术
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2025
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IF 16
Bo Xu,Shichen Yuan,Linqin Wang,Xiansheng Li,Zhuang Hu,Haibo Zeng
Room temperature (RT) synthesized mixed bromine and chlorine CsPbBrxCl3–x perovskite quantum dots (Pe-QDs) offer notable advantages for blue quantum dot light-emitting diodes (QLEDs), such as cost-effective processing and narrow luminescence peaks. However, the efficiency of blue QLEDs using these RT-synthesized QDs has been limited by inferior crystallinity and deep defect presence. In this study, we demonstrate a precise approach to constructing high-quality gradient core–shell (CS) structures of CsPbBrxCl3–x QD through anion exchange. Characterization shows that these CS-QDs exhibit a type-I band alignment with a high bromine concentration in the core and a high chlorine concentration in the shell. This unique configuration results in a larger exciton binding energy and reduced defect density, leading to enhanced exciton radiative recombination. Consequently, QLEDs using CS-QDs achieve an external quantum efficiency (EQE) of 16.28%, a maximum luminance of 8423.35 cd/m2, and improved operational stability, surpassing the 12.80% EQE of reference QLEDs made with homogeneous structured QDs (HS-QDs). These findings present a strategy for developing high-quality RT-synthesized blue CS-QDs, marking a significant advancement in the field of efficient pure-blue QLEDs.
研究领域:
材料科学
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光学工程
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DOI
PubMed
高影响因子
Surfaces and Interfaces
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2021
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IF 4.837
Lu Huang,Can Liu,Cewei Ren,Ziqi Nie,Xinlin Xiong,Lichao Zeng,Wenqing Zhu,Weiguang Yang,Linjun Wang
ABSTRACT Controlling perovskite phase composition plays an important role in improving the quality of quasi-2D blue emissive perovskite thin films to realize spectrally stability of perovskite LED (PeLED). Herein, the high quality quasi-2D perovskite thin films were prepared by low pressure flashing induce crystallization (LPFC) method, which promoted surface coverage of perovskites to control the removal speed of solvent mixtures unanimously by adjusting the pressure of post-treatment from 1 KPa to 101 KPa. Compared to the common post-treatment method, perovskite thin films produced different quasi-2D phase under the pressure of 20 KPa by LPFC method and corresponding devices possessed high luminance with spectrally stability. Furthermore, the facile LPFC method promoted the volatile speed of high boiling point single solvent and accelerate the crystallization process to realize high quality of quasi-2D perovskite thin films prepared at room temperature.
研究领域:
材料科学
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光学工程
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DOI
高影响因子
ORGANIC ELECTRONICS
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2022
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IF 3.868
Songman Ju,Chaomin Mao,Yang Liu,Yangbin Zhu,Zhongwei Xu,Kaiyu Yang,Tailiang Guo,Hailong Hu,Fushan Li
Perovskite quantum dots light-emitting diodes (PQLEDs), due to the advantages of high luminous efficiency, high color purity, adjustable spectral range, etc., has an excellent prospect in the next generation of high-definition displays. As an indispensable part of displays, blue PQLEDs are usually achieved by mixing halogen, which, however, will lead to halogen ion migration and phase separation of perovskite material at high temperature and bias pressure, thus make the electroluminescent spectrum redshift. In this manuscript, we propose a strategy to inhibit phase separation of blue perovskite quantum dots (PQDs) by introducing alkali metal , and obtain stable perovskite quantum dot light-emitting diodes. The PQLEDs based on this strategy show an external quantum efficiency (EQE) of 1.87% and a brightness of 3757 cd m −2 , and can still guarantee stable electroluminescence (EL) spectra at a bias of up to 14 V. The work is beneficial for probing into the mechanism of suppressing the phase separation of mixed halogen blue PQDs and offer a promising strategy to enhance the color stability of blue PQLEDs.
研究领域:
材料科学
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光电技术
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
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2024
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IF 8
Lihui Liu,Yun Wang,Chenxi Liu,Jian Chen,Zijie Hou,Xuejing Liu,Kun Cao,Wei Shen,Shufen Chen
Metal halide perovskite light-emitting diode (PeLED) is the most promising candidate for next-generation display technology. However, the development of the blue PeLEDs is far behind the expectations. Mixed-halide perovskites demonstrate to be the most facile method to realize blue emission, which confronts serious spectra stability problem arising from the halide segregation. Here, a polymerizable passivator is introduced into the Cl/Br-mixed perovskites, which can simultaneously cross-link perovskite grains by interconnecting halides through hydrogen bonding, and transport the carriers through its π-conjugated backbone. Consequently, this cross-linked blue perovskite film demonstrates a significantly improved spectra stability under various external stimuli of high humidity, UV radiation, and electrical field, and the corresponding PeLED yields a decent external quantum efficiency of 12.0% at high brightness of 3390 cd m −2 with the emission at 478 nm. Notably, this work provides a unique cross-link agent with in situ polymerizability to address the ion migration and phase segregation issues without sacrificing the conducting capacity in mixed-halide perovskites.
研究领域:
材料科学
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光电技术
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化学工程
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DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 32
·期 8
·2105164
·
IF 18.808
Weigang Ding,Hongli Liu,Shuai Zhang,Dingding Qiu,Xianggao Li,Shirong Wang
Perovskite films have emerged as candidates for light-emitting diodes on accounts of excellent optical properties and low cost. Construction of quasi-2D perovskite films by incorporating organic ammonium is an effective method to manufacture a pinhole-free film with high photoluminescence quantum yield (PLQY). However, excess organic ammonium hampers carrier mobility through forming insulating capping layer and facilitates the formation of alow-dimensional perovskite ( n = 1 and n = 2) phase that accelerates non-radiative recombination, resulting in poor performance of light-emitting diodes. In this work, formamidine acetate is added into the quasi-2D perovskite to modulate the optical and electrical properties of the perovskite films (CsFA-Ac). Acetate ions are in favor of washing away excess ammonium and formamidine ions are beneficial to increase the formation energy of low-dimensional ( n = 2) phase. As a result, the quasi-2D perovskite is transformed into 3D perovskite. The PLQY of the obtained CsFA-Ac perovskite films is boosted to 59.9% and carrier mobility is enhanced to 47.3 cm 2 V -1 s -1 . Blue perovskite light-emitting diode based on the CsFA-Ac film is endowed with a prominent EQE of 8.8% (average 7.0%) at 477 nm. This work demonstrates a strategy for the development of efficient perovskite light-emitting diodes.
研究领域:
材料科学
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光电工程
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DOI
高影响因子
DYES AND PIGMENTS
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2024
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IF 4.1
Guiru Ding,Xudong Liu,Weidong Yu,Yan Bing,Ning Sun,Hongji Jiang
To investigate the effects of trifluoromethyl and tert -butyl moieties on the general optoelectronic properties of star-shaped hosts based on phenyls substituted carbazole, we used 3,6,9-tris (4-( tert -butyl)-phenyl)-9 H -carbazole ( M1 ) as a reference, and different numbers of electron-withdrawing 3,5-bis(trifluoromethyl) benzene were introduced into 3, 6 and 9 positions of carbazole to obtain compounds 9-(3,5-bis(trifluoromethyl)phenyl)-3,6-bis(4-( tert -butyl)phenyl)-9 H -carbazole ( M3) , 3,6-bis(3,5-bis(trifluoromethyl)phenyl)-9-(4-( tert -butyl)phenyl)-9 H -carbazole ( M5) and 3,6,9-tris(3,5-bis(trifluoromethyl)phenyl)-9 H -carbazole ( M6) . After the introduction of 3,5-bis (trifluoromethyl) benzene, the thermal temperature at 5 % mass loss of M3 , M5 and M6 decreased to 344 °C, while the glass transition temperature and melting point of M3 and M5 showed a significant increase. However, M6 did not show obvious glass transition, but its melting point also showed a significant increase. M3 crystallized at 125 °C as evidenced by differential scanning calorimetry, and the linking model of M3 is helpful to crystalize. In addition, when compared with those of M1 , the fluorescence emission peaks of M3 and M6 showed a blue-shift, while M5 showed a red-shift, all of which were in the deep blue emission range. The color purity of blue light for M1 in tetrahydrofuran solution is the highest, and M1 exhibit aggregation-induced emission characteristics. Compared to the photoluminescence quantum efficiency (PLQY) of compound M1 of 39 % in toluene, the PLQYs of M3 and M6 decreased to 34 % and 29 %, and the PLQY of M5 increased to 46 %. The function of the lowest unoccupied molecular orbital trap of M3 film under the external electrical field will increase, which not only offsets the increasing effect of the electrical field to the electron carrier and further decreases the carrier mobility when the electrical field increase, and the same situation is also feasible for the highest occupied molecular orbital traps in M5 , M6 and M1 . The organic blue light emitting diodes were prepared by using M1 , M3 , M5 and M6 as the hosts of bis [2-(4,6-difluorophenyl)pyridinato-C 2 ,N](picolinato)iridium, and the optimized device of M1 as the host showed the best performance with a maximum luminescence brightness of 2978 cd/m 2 , maximum current efficiency of 39.42 cd/A and maximum external quantum efficiency of 18.36 %.
研究领域:
材料科学
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光电化学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Yingyi Nong,Jisong Yao,Jizhong Song
The mixed-halide CsPbCl 3-x Br x perovskite quantum dots (QDs) have emerged as promising candidates for pure-blue light-emitting diodes (LEDs). However, the widely existing defects in these mixed-halide perovskites, arising from uncontrollable crystallization and low Cl vacancy formation energy, significantly restrict the device performance. Herein, a cation-anion pair-assisted synthesis strategy is proposed to obtain high-quality CsPbCl 3-x Br x QDs. Guanidinium sulfate (GA 2 SO 4 ) is introduced during the synthesis process, in which sulfate anions passivate undercoordinated Pb 2+ defects, effectively reducing the non-radiative recombination, and the guanidinium cations interact with halides on the QD surface via hydrogen bonds, inhibiting the formation of Cl vacancy defects. Benefiting from this synergistic passivation effect of the cation-anion pair, the photoluminescence quantum yield of the QDs increases from 42% to 86%. Meanwhile, the QDs exhibit high crystalline quality, which facilitates the transport of charge carriers. Resultantly, the QLEDs achieve a record external quantum efficiency of 24.9% at 470 nm, showing a 1.6-fold improvement over that of the control devices. This work demonstrates that a synergistic ion-pair passivation strategy is a practical design approach for realizing efficient and stable pure-blue perovskite LEDs.
研究领域:
材料科学
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纳米技术
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半导体器件
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光电子学
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凝聚态物理
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无机化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2019
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IF 4.309
Congyang Zhang,Qun Wan,Bo Wang,Weilin Zheng,Mingming Liu,Qinggang Zhang,Long Kong,Liang Li
Recently, two-dimensional colloidal perovskite nanoplatelets (NPLs) have attracted great attention as one of the most promising candidate blue emitters due to their large exciton binding energy and precisely tunable thickness. However, the lack of techniques to simultaneously obtain highly emissive and stable perovskite NPLs has limited the successful exploitation of highly efficient perovskite NPL-based optoelectronic devices. Herein, we report the surface ligand-engineering strategy to enhance the photoluminescence quantum yields and stability of perovskite NPLs using a short-chain halide ion-pair ligand. Benefits from the shorter-chain ligand treatment, the electronic conductivity, and carrier injection of perovskite NPL films have also been improved significantly, enabling us to realize highly efficient blue (469 nm) electroluminescence devices with a peak external quantum efficiency of 1.42%, which is among the highest efficiencies of colloidal pure-bromide perovskite NPL-based light-emitting diodes.
研究领域:
材料科学
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光电子学
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纳米技术
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）