NATURE
·
2025
·Vol. 641
·期 8062
·352-357
·
IF 48.5
Song Yong-Hui,Li Bo,Wang Zi-Jian,Tai Xiao-Lin,Ding Guan-Jie,Li Zi-Du,Xu Huaiyu,Hao Jing-Ming,Song Kuang-Hui,Feng Li-Zhe,Hu Ya-Lan,Yin Yi-Chen,Zhu Bai-Sheng,Zhang Guozhen,Ju Huanxin,Zheng Guanhaojie,Hu Wei,Lin Yue,Fan Fengjia,Yao Hong-Bin
Metal-halide perovskites are promising light-emitter candidates for next-generation light-emitting diodes (LEDs) 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 . Achieving high brightness and efficiency simultaneously in pure-red perovskite LEDs (PeLEDs) is an ongoing goal 9 , 10 . Three-dimensional (3D) CsPbI 3- x Br x emitters have excellent carrier transport capability and high colour purity, which could allow efficient and ultrabright pure-red PeLEDs. However, such devices are prone to efficiency roll-off, resulting in low efficiency and low brightness under high current density. Here, by using electrically excited transient absorption spectroscopy, we discovered the efficiency roll-off was induced by hole leakage. Therefore, we developed a CsPbI 3- x Br x intragrain heterostructure containing narrow bandgap emitters and wide bandgap barriers to confine the injected carriers. The wide bandgap barrier was incorporated by introducing strongly bonding molecules into the [PbX 6 ] 4− framework to expand the 3D CsPbI 3- x Br x lattice. This strategy resulted in bright and efficient pure-red PeLEDs, with a high brightness of 24,600 cd m −2 , maximum external quantum efficiency of 24.2% and low efficiency roll-off, maintaining a 10.5% external quantum efficiency at a high luminance of 22,670 cd m −2 .
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Optical Materials
·
2022
·Vol. 10
·期 11
·2200189
·
IF 10.05
Shixu Yang,Chenghao Bi,Wei Dong,Xiaoyu Zhang,Weitao Zheng,Wallace C. H. Choy,Jianjun Tian
Perovskite quantum dot (QD) charging is prone to occur during light-emitting diode (LED) operation due to the electron accumulation inside the QD emitters, which is caused by the unbalanced charge injection and carrier transportation. Here in order to address this issue, an electron attractor of phenethylammonium (PEA + ) is introduced to the surface of perovskite QDs. The PEA + conjugated ligands can reversibly store and release electrons driven by the electron local density of states redistribution, which enhances the delocalization of electrons in QDs, and thus suppresses QD charging at high carrier concentrations, as evidenced by the excitation energy dependent photoluminescence. Besides, PEA + down-shifts the Fermi level of perovskite QDs, consequently increases the hole concentration, leading to greatly improved hole conduction. Halogen-rich synthesis environment also reduces the number of halogen vacancies, consequently narrows the distribution of electronic states at the band edges, leading to slightly improved electron conduction. Taking advantage of the enhanced electron delocalization and improved charge transportation, the CsPbI 3 QDs LEDs show the maximum external quantum efficiency (EQE) of 15.6% with a low efficiency roll-off, and the maximum luminance of 1634 cd m −2 .
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
Nano Energy
·
2021
·
IF 17.881
Yuliang Ye,Jiaxiang Wang,Yinglin Qiu,Jiahui Liu,Bingqing Ye,Zunxian Yang,Zhipeng Gong,Lei Xu,Yuanqing Zhou,Qiaocan Huang,Zihong Shen,Wenbo Wu,Songman Ju,Lucheng Yu,Yihang Fu,Fushan Li,Tailiang Guo
Recently, perovskite quantum dots (PQDs) were employed as promising emitters in light-emitting diode devices (LEDs) mainly owing to their marvelous photoelectronics properties. However, these perovskite QLEDs suffered from the inefficient performance, especially their serious efficiency roll-off probably due to the exciton recombination dynamic in the interface of PQDs films and charge imbalance resulting from low electrical transportation. Herein, sodium dodecyl sulfate (SDS) was effectively introduced to synthesize PQDs with many excellent properties and eventually suppressed the efficiency roll-off of QLEDs. SDS-based PQDs films exhibited obviously enhanced radiative recombination , reduced trap density, and increased carrier mobility , especially the transportation of electrons. Therefore, the charge carrier was balanced at high current density together with the remarkably suppressed efficiency roll-off. QLEDs fabricated by SDS-capped PQDs exhibited significantly improved maximum brightness of 193,810 cd/m 2 , and achieve the external quantum efficiency of 10.13%. More importantly, the EQE roll-off of QLED optimized in the thickness of emitting layer was only 1.5% at the current density of 200 mA/cm 2 , representing a prominent achievement of our strategy.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2016
·
IF 2.183
Hua Ye,Kaifeng Zhou,Hongyu Wu,Kai Chen,Gaozhan Xie,Jingang Hu,Guobing Yan,Songhua Ma,Shi-Jian Su,Yong Cao
A series of novel molecules with wide bandgap based on electron-withdrawing diphenyl phosphine oxide units and electron-donating carbazolyl moieties through insulated unique linkages of flexible chains terminated by oxygen or sulfur atoms as solution-processable host materials were successfully synthesized for the first time, and their thermal, photophysical, and electrochemical properties were studied thoroughly. These materials possess high triplet energy levels ( E T , 2.76–2.77 eV) due to the introduction of alkyl chain to interrupt the conjugation between electron-donor and electron-acceptor. Such high E T could effectively curb the energy from phosphorescent emitter transfer to the host molecules and thus assuring the emission of devices was all from the blue phosphorescent emitter iridium (III) bis [(4,6-difluorophenyl)-pyridinate- N ,C2′]picolinate (FIrpic). Among them, the solution-processed device based on CBCR6OPO without extra vacuum thermal-deposited hole-blocking layer and electron-transporting layer showed the highest maximum current efficiency (CE max ) of 4.16 cd/A. Moreover, the device presented small efficiency roll-off with current efficiency (CE) of 4.05 cd/A at high brightness up to 100 cd/m 2 . Our work suggests the potential applications of the solution-processable materials with wide bandgap in full-color flat-panel displays and organic lighting.
研究领域:
材料科学
·
有机电子学
✓ 已验证
DOI
高影响因子
ACS Nano
·
2025
·
IF 16
Jingjing Cao,Wenji Zhan,Meng Ren,Yao Wang,Haifei Wang,Ni Zhang,Yuetian Chen,Tianfu Wang,Yanfeng Miao,Yixin Zhao
The application of promising perovskite light-emitting diodes (PeLEDs) faces a significant challenge known as efficiency roll-off, which refers to the decline in external quantum efficiency (EQE) at high current densities. This issue arises mainly from high trap densities in perovskite films and imbalanced carrier injection, which limit improvements in brightness and stability of PeLEDs. Here, we develop a green solvent strategy using γ-valerolactone (GVL) to suppress efficiency roll-off in PeLEDs. This strategy effectively slows down the crystallization kinetics, yielding cubic-phase formamidinium lead triiodide (α-FAPbI3) films with reduced trap states, enhanced charge carrier injection, and suppressed Auger recombination. As a result, we achieve a record radiance of 1411 W sr–1 m–2 for GVL-based PeLEDs. These PeLEDs exhibit a substantially reduced efficiency roll-off, maintaining an EQE above 20% even at a high current density of 900 mA cm–2. Our findings highlight the potential of the green solvent approach for developing high-brightness, high-efficiency PeLEDs for practical applications.
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
Journal of Materials Chemistry C
·
2024
·
IF 5.7
Xingxing Duan,Bufan Yu,Guangrong Jin,Dengliang Zhang,Jiangshan Chen,Dongge Ma
During the past few years, significant progress has been achieved with blue perovskite light-emitting diodes (PeLEDs) based on quasi-two-dimensional (quasi-2D) perovskites with chloride (Cl) and bromine (Br) ions toward improving their external quantum efficiencies (EQEs). However, mixed-halide quasi-2D PeLEDs still suffer from serious efficiency roll-off and spectral instability. Here, modification of mixed-Cl/Br quasi-2D perovskites with a multi-functional additive is proposed to achieve efficient blue PeLEDs with reduced efficiency roll-off and stable electroluminescence (EL) spectra. Aminophylline (AMP) with Lewis base characteristics was employed as the additive to incorporate with the CsPb(Cl/Br)3 based quasi-2D perovskites. It was observed that the introduction of the AMP additive suppressed the low dimensional phases in the quasi-2D blue perovskite film, leading to the carriers being harvested for radiative recombination rather than being located at the low dimensional phases. In addition, the AMP additive, containing carbonyl and imine groups, can coordinate with the uncoordinated Pb2+, which enables the passivation of defects and the reduction of trap-assisted non-radiative recombination in the blue quasi-2D perovskite films. As a result, based on the AMP-modified quasi-2D perovskites, the champion PeLED achieved a maximum EQE of 13.2% with a stable EL peak at 484 nm, which is 1.6 times that of the pristine device without the AMP additive. Importantly, the AMP-modified blue PeLEDs maintained an EQE as high as 11.5% at a high luminance of 1000 cd m−2, demonstrating a significantly reduced EQE roll-off. Meanwhile, the AMP-modified devices presented more stable spectra than the pristine devices under various voltages or continuous operation at an identical initial luminance. This study demonstrated a facile modification strategy by using a multi-functional additive to facilitate the improvement of efficiency roll-off and spectral stability in mixed-Cl/Br quasi-2D blue PeLEDs.
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
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Tao Hua,Yu-Chun Liu,Chih-Wei Huang,Nengquan Li,Changjiang Zhou,Zhongyan Huang,Xiaosong Cao,Chung-Chih Wu,Chuluo Yang
Highly efficient blue thermally activated delayed fluorescence (TADF) materials with high horizontal dipole orientation (Θ // ) remain a big challenge due to the concentration quenching effects and serious efficiency roll-offs in their corresponding organic light-emitting diodes (OLEDs). We herein report two novel TADF compounds, namely 2TDBA-SBA and TDBA-SBA, which were facilely synthesized by utilizing a rigid oxygen-bridged cyclized triarylboron-based unit (TDBA) as the acceptor and a spiro acridine (SBA) as the donor. Benefiting from the rigid and planar skeleton of the acceptor and the linear molecular shape, high Θ // s and photoluminescence quantum yields (PLQYs) of ∼ 90% were achieved. Significantly, TDBA-SBA exhibited excellent TADF properties with a short delayed fluorescence lifetime of only 684 ns and narrow full-width at half-maximum (FWHM) of 44 nm in solution state, accompanied by the high PLQYs of over 80% at high doping concentrations, manifesting the alleviated exciton quenching effects. Consequently, OLEDs based on TDBA-SBA achieved a high maximum external quantum efficiency (EQE) of 29.3% and a maximum brightness of 27663 cd cm −2 . Importantly, an EQE over 20% was realized even at the high brightness of 10000 cd cm −2 , signifying a small efficiency roll-off.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Qiaopeng Cui,Xiang Zhang,Dingshuo Zhang,Xinyang Wang,Zichao Ma,Zaishang Long,Mo Zhou,Jiajun Luo,Haiping He,Zhizhen Ye,Xingliang Dai
Perovskite light-emitting diodes (PeLEDs) have been substantiated as promising candidates for high-efficiency electroluminescence. However, the maximum external quantum efficiency (EQE) of state-of-the-art PeLED is typically achieved at relatively low current densities and exhibits severe efficiency roll-off under intense electrical excitation, thereby restricting their development in high-power applications. Specifically, the uniformity of electrical injection has usually been neglected in optimization strategies, primarily due to inadequate comprehension of the microscale injection. In this study, a modified deposition method, marked static reaction deposition, is developed. The residence of precursor solution on the magnesium-doped zinc oxide substrate enables the perovskite crystalline growth homogeneously, thereby enabling the construction of a perovskite polycrystalline emission film with an ultra-low root mean square roughness of 0.72 nm. The resultant enhancement in electrical injection uniformity effectively suppresses localized carrier over-injection and mitigates EQE roll-off. The fabricated PeLED demonstrates a maximum luminance of 590,000 cd m −2 at a high current density of 964 mA cm −2 and maintains an EQE exceeding 10% at current densities up to 1000 mA cm −2 . These findings delineate a novel and broadly applicable optimization paradigm for realizing high-luminance, low roll-off, and efficient PeLEDs.
研究领域:
材料科学
·
光电子学
·
纳米技术
·
半导体器件
·
薄膜制备
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2024
·
IF 15.8
Xinquan Gong,Xiaoming Hao,Junjie Si,Yunzhou Deng,Kai An,Qianqing Hu,Qiuting Cai,Yun Gao,You Ke,Nana Wang,Zhuopeng Du,Muzhi Cai,Zhizhen Ye,Xingliang Dai,Zugang Liu
Developing green perovskite light-emitting diodes (PeLEDs) with a high external quantum efficiency (EQE) and low efficiency roll-off at high brightness remains a critical challenge. Nanostructured emitter-based devices have shown high efficiency but restricted ascending luminance at high current densities, while devices based on large-sized crystals exhibit low efficiency roll-off but face great challenges to high efficiency. Herein, we develop an all-inorganic device architecture combined with utilizing tens-of-nanometers-sized CsPbBr3 (TNS-CsPbBr3) emitters in a carrier-confined heterostructure to realize green PeLEDs that exhibit high EQEs and low efficiency roll-off. A typical type-I heterojunction containing TNS-CsPbBr3 crystals and wide-bandgap Cs4PbBr6 within a grain is formed by carefully controlling the precursor ratio. These heterostructured TNS-CsPbBr3 emitters simultaneously enhance carrier confinement and retain low Auger recombination under a large injected carrier density. Benefiting from a simple device architecture consisting of an emissive layer and an oxide electron-transporting layer, the PeLEDs exhibit a sub-bandgap turn-on voltage of 2.0 V and steeply rising luminance. In consequence, we achieved green PeLEDs demonstrating a peak EQE of 17.0% at the brightness of 36,000 cd m–2, and the EQE remained at 15.7% and 12.6% at the brightness of 100,000 and 200,000 cd m–2, respectively. In addition, our results underscore the role of interface degradation during device operation as a factor in device failure.
研究领域:
材料科学
·
光电子学
·
纳米技术
·
半导体物理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）