ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Yabing Sun,Haoju Li,Xin Zhou,Yonggang Min,Yannan Qian
It is well known that the balanced charge injection helps prepare high-performance red light-emitting diodes (LEDs) in the electroactive material CsPbBr x I 3- x quantum dots (QDs). Employing a hydrothermal method, we synthesized MoO 2 nanocrystals and doped them into Poly(3,4-ethylenedioxythiophene) /poly(styrenesulfonate) (PEDOT:PSS). The results show that the synthesized MoO 2 nanocrystals can modulate the work function of PEDOT:PSS and enhance the conductivity of the PEDOT:PSS films, which is attributed to disrupting the hydrogen bond between PEDOT and PSS, and inducing the transition of PEDOT from benzoid to quinoid structure. In the PEDOT:PSS- x MoO 2 film, the work function increases from 4.9 eV to 5.09 eV when the content of x is 15%, which reduces the energy barrier between the PEDOT:PSS- x MoO 2 and the hole transport layer: poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzi (poly-TPD), thus promoting the hole transport and improving the V on of the devices. Additionally, the device's external quantum efficiency (EQE) reaches a maximum value of 7.53% at x = 15% enabling an improvement of 2.6 times over the base device (EQE=2.10%). This work proves that PEDOT:PSS- x MoO 2 as a hole transport layer is an effective material for preparing high-performance QD-LEDs.
研究领域:
材料科学
·
光电技术
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2024
·Vol. 12
·期 22
·2400722
·
IF 8
Zhen-Yu Ma,Bai-Sheng Zhu,Xue-Chen Ru,Yi-Chen Yin,Li-Zhe Feng,Guan-Jie Ding,Mei-Yu Zhou,Yong-Hui Song,Hong-Min Zhou,Cheng-Ming Wang,Jing-Ming Hao,Hong-Bin Yao
Inorganic CsPbI 3 perovskite has great potential to fabricate deep-red light-emitting diodes (LEDs) owing to excellent color purity, thermal stability, and carrier mobility. However, fabricating high-quality CsPbI 3 thin films for high-performance LEDs remains challenging. While it is demonstrated that hydrogen bonds between organic ammonium cations and molecule additives can lead to high-quality organic–inorganic hybrid perovskite films, this method cannot be applied to CsPbI 3 thin films due to the absence of hydrogen bonds between Cs + ions and additives. In this study, an amorphous complex-seed-crystal growth process to fabricate high-quality γ -CsPbI 3 cuboid crystallite thin films, is reported. During the initial annealing, the metastable intermediates formed crystal nucleate seeds and transformed into amorphous complex intermediates, maintaining stability at an elevated temperature for perovskite crystallization. With prolonged annealing, the amorphous complex around the nucleate seeds gradually converts to γ -CsPbI 3 perovskite, enabling us to fabricate CsPbI 3 thin films with high crystallinity and orientation. The resulting deep-red LEDs exhibit a peak external quantum efficiency (EQE) of 16.5% and a high maximum luminance of 3158 cd m −2 . Moreover, the devices show significantly suppressed efficiency roll-off, maintaining an EQE of 14.8% even under a high current density of 500 mA cm −2 .
研究领域:
材料科学
·
光电技术
✓ 已验证
产品关联
DOI
高影响因子
Optical Materials Express
·
2021
·Vol. 11
·期 2
·355-370
·
IF 3.442
Dongxun Chen,Shihai Miao,Yanjie Liang,Yanjie Liang,Yanjie Liang,Weili Wang,Shao Yan,Jianqiang Bi,Jianqiang Bi,Kangning Sun
Core-shell Bi2SiO5 nanosystem with uniform morphology and narrow size distribution has been successfully synthesized via a facile template-assisted route. With the introduction of Eu3+, detailed studies are performed to evaluate its promise as Eu3+-based phosphor host. The yielded Bi2SiO5:Eu3+ nanospheres are proven to be pure tetragonal phase via X-ray diffraction and Rietveld refinement. Moreover, the phosphor particles consist of monodisperse spheres with an average diameter of approximately 285 nm by high-resolution electron microscopy. When excited by near-ultraviolet (NUV) light, the abnormally high-intensity emission at 703 nm arising from the 5D0→7F4 transition of Eu3+ is observed. The temperature-dependent photoluminescence spectra show that the optimized Bi2SiO5:20%Eu3+ have satisfactory thermal stability with 63.7% of emission intensity at 423 K relative to 303 K. The deep-red light-emitting diode (LED) device fabricated by coating NUV chip with the Bi2SiO5:20%Eu3+ phosphors is demonstrated. The newly-developed Bi2SiO5:Eu3+ nanophosphors display commendable photoluminescence properties, demonstrating their promise as deep-red phosphor candidates for use in phosphor-converted LEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2021
·Vol. 10
·期 2
·2101517
·
IF 9.926
Xin Zhou,Jibin Zhang,Xuan Tong,Yabing Sun,Haiyan Zhang,Yonggang Min,Yannan Qian
Although all-inorganic CsPbBr x I 3− x perovskite quantum dots (PeQDs) are increasingly being used as a competitive material for pure red perovskite light-emitting diodes (PeLEDs), they suffer from low luminescent ability and poor stability. In this study, an In 3+ -doped CsPbBr x I 3− x PeQD solution exhibits a near-unity photoluminescence quantum yield (PLQY) of ≈99.8% and superior stability for more than half a year in atmosphere. As far as known, this is the highest PLQY and stability achieved for mixed halide PeQDs. In 3+ ion doping not only reduces the surface vacancy defects because of the partial substitution of Pb 2+ by the smaller radii of In 3+ ions, but also enhances the formation energy of CsPbBr x I 3− x PeQDs based on first-principles calculations. Compared with pristine LEDs based on CsPbBr x I 3− x , the pure red PeLEDs based on In 3+ -doped CsPbBr x I 3− x display a higher luminance of 423 cd m -2 , fivefold external quantum efficiency improvement up to 11.2%, and increased stability, providing a feasible and promising perspective for developing In 3+ -doped CsPbBr x I 3− x PeQDs applied efficiently in advanced light emitters for solid-state lighting and displays.
研究领域:
材料科学
·
光电技术
✓ 已验证
DOI
高影响因子
Journal of the American Chemical Society
·
2022
·
IF 16.383
Qian Zhang,Yong-Hui Song,Jing-Ming Hao,Yi-Feng Lan,Li-Zhe Feng,Xue-Chen Ru,Jing-Jing Wang,Kuang-Hui Song,Jun-Nan Yang,Tian Chen,Hong-Bin Yao
All-inorganic CsPbI3 perovskite is attractive for deep-red light-emitting diodes (LEDs) because of its excellent carrier mobility, high color purity, and solution processability. However, the high phase transition energy barrier of optically active CsPbI3 black phase hinders the fabrication of efficient and bright LEDs. Here, we report a novel α-BaF2 nanoparticle substrate-promoted solution-processable heteroepitaxial growth to overcome this hindrance and obtain high-quality optically active γ-CsPbI3 thin films, achieving efficient and bright deep-red LEDs. We unravel that the highly exposed planes on the α-BaF2 nanoparticle-based heteroepitaxial growth substrate have a 99.5% lattice matching degree with the (110) planes of γ-CsPbI3. This ultrahigh lattice matching degree initiates solution-processed interfacial strain-free epitaxial growth of low-defect and highly oriented γ-CsPbI3 thin films on the substrate. The obtained γ-CsPbI3 thin films are uniform, smooth, and highly luminescent, based on which we fabricate efficient and bright deep-red LEDs with a high peak external quantum efficiency of 14.1% and a record luminance of 1325 cd m–2.
研究领域:
材料科学
·
光电技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Crystals
·
2022
·Vol. 12
·期 10
·1382
·
IF 2.67
Xinhua Chen,Qingliang Xu,Fayaz Hussain,Chen Yang,Weiqin Sheng,Xinjiang Luo,Bing Liu,Shikuan Sun,Dawei Wang,Kaixin Song
Red LEDs with a high color purity and high color rendering index are often used to compensate for the lack of red-light components in current white LEDs. Therefore, the new type of garnet-structured high color purity red phosphor Y2−xSrAl4SiO12: xEu3+was synthesized by the solid-state method. The band gap structure of the host matrix was studied through the DFT calculation and found that the matrix belongs to a direct band gap structure with a band gap size of 4.535ev. The phosphor exhibits a wide excitation spectrum under the monitoring of 710 nm. The strongest excitation wavelength is 393 nm, and it exhibits bright red light under the excitation of 393 nm, and the emission peak positions are located at 570 nm, 597 nm, 613 nm, 650 nm, 710 nm and 748 nm, respectively, which are attributed to the5D0→7Fjof Eu3+(j = 0–5) electronic transitions. In the crystal structure of Y2SrAl4SiO12, Eu3+occupies a symmetry site. The compositional changes and thermal studies found favorable at 20% mol. At this concentration, the luminescence intensity gradually weakened due to the Eu3+electric multi-level interaction. It is worth noting that the emission intensity of Y2SrAl4SiO12: 20%Eu3+at 433 K can be maintained to 92% of that at 293 K. Finally, we combined it with the NUV chip and packaged it into a red LED with a color purity of up to 90% and a correlated color temperature of 1492 K. The high purity, low color temperature and thermal stability indicate that it has a place in LED applications.
研究领域:
材料科学
·
光学工程
·
固体化学
·
半导体物理
·
发光材料
·
照明技术
✓ 已验证
DOI
高影响因子
ADVANCED MATERIALS
·
2025
·
IF 26.8
Wenji Zhan,Haifei Wang,Jiahao Guo,Yugang Liang,Yanming Wang,Jixin Wu,Zhengzheng Dang,Ni Zhang,Jingjing Cao,Yingping Fan,Yu Zou,Bowei Li,Yao Wang,Yuetian Chen,Yanfeng Miao,Yixin Zhao
Deep-red light-emitting diodes (LEDs) with 690−710 nm emission show high significance in optical, agricultural, and biomedical applications. As primary candidates for deep-red emitters, all-inorganic CsPbI 3 films suffer from fused large grains with abundant trap states, leading to inferior performance of deep-red perovskite LEDs (PeLEDs). Here we report CsPbI 3 nanocrystal films with strong space confinement and notable performance at ∼700 nm of deep-red emission via bulk fabrication. The dual roles of diaza-18-crown-6 dihydriodide additive as crystallization regulator and Lewis base ligand trigger more nucleation sites, retarded grain growth and passivated trap states, ensuring the crystallization of high-quality space-confined CsPbI 3 nanocrystal films. This approach establishes a record-high external quantum efficiency (EQE) of 23.4% for deep-red PeLEDs, and achieves a maximum luminance of 10152 cd m −2 . Low roll-off is also demonstrated that EQE maintain over 20% under a high current density of 900 mA cm −2 , which is superior to state-of-the-art deep-red organic and quantum-dot LEDs. The T 50 operating lifetime is estimated to be 234 h at an initial radiance of 6.3 W sr −1 m −2 . This work provides an effectual strategy to accelerate radiative recombination and enhance the performance of CsPbI 3 -based deep-red PeLEDs.
研究领域:
材料科学
·
光电子学
·
纳米技术
·
钙钛矿发光二极管
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）