- 标题
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- 实验方案
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Colloidal Synthesis of Ternary Copper Halides Nanocrystals for High-Efficiency Deep-Blue Light-Emitting Diodes with a Half-Lifetime Above 100 Hours
摘要： Currently, the blue perovskite light-emitting diodes (PeLEDs) suffer from a compromise in lead-toxicity and poor operation stability, and most previous studies have struggled to meet the crucial blue NTSC standard. In this study, electrically-driven deep-blue LEDs (~445 nm) based on zero-dimensional (0D) Cs3Cu2I5 nanocrystals (NCs) were demonstrated with the color coordinates of (0.16, 0.07) and a high external quantum efficiency of ~1.12%, comparable with the best-performing blue LEDs based on lead-halide perovskites. Encouraged by the remarkable stability of Cs3Cu2I5 NCs against heat and environmental oxygen/moisture, the proposed device was operated in a continuous current mode for 170 h, producing a record half-lifetime of ~108 h. The device stability was further verified by an aggressive thermal cycling test (300?360?300 K) and a 35-day storage test. Together with the eco-friendly features and facile colloidal synthesis technique, the 0D Cs3Cu2I5 NCs can be therefore regarded as a promising candidate for deep-blue LEDs applications.
关键词： self-trapped excitons,light-emitting diodes,stability,Cs3Cu2I5 nanocrystals,deep-blue
更新于2025-09-23 15:21:01
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Efficient and Stable Deep-Blue Fluorescent Organic Light-Emitting Diodes Employing a Sensitizer with Fast Triplet Upconversion
摘要： Multiple donor–acceptor-type carbazole–benzonitrile derivatives that exhibit thermally activated delayed fluorescence (TADF) are the state of the art in efficiency and stability in sky-blue organic light-emitting diodes. However, such a motif still suffers from low reverse intersystem crossing rates (kRISC) with emission peaks <470 nm. Here, a weak acceptor of cyanophenyl is adopted to replace the stronger cyano one to construct blue emitters with multiple donors and acceptors. Both linear donor–π–donor and acceptor–π–acceptor structures are observed to facilitate delocalized excited states for enhanced mixing between charge-transfer and locally excited states. Consequently, a high kRISC of 2.36 × 106 s?1 with an emission peak of 456 nm and a maximum external quantum efficiency of 22.8% is achieved. When utilizing this material to sensitize a blue multiple-resonance TADF emitter, the corresponding device simultaneously realizes a maximum external quantum efficiency of 32.5%, CIEy ≈ 0.12, a full width at half maximum of 29 nm, and a T80 (time to 80% of the initial luminance) of > 60 h at an initial luminance of 1000 cd m?2.
关键词： stable deep-blue devices,sensitized emission,high reverse intersystem crossing,thermally activated delayed fluorescence,multiple donors and acceptors
更新于2025-09-23 15:21:01
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Realization of deep-blue TADF in sterically controlled naphthyridines for vacuum- and solution-processed OLEDs
摘要： Narrow-band deep-blue (emission peak < 460 nm) TADF emitters are in demand for commercial OLED display applications, yet the development of efficient emitters with low efficiency roll-off is very challenging. To address this issue herein we studied carbazole-naphthyridine (donor-acceptor) based blue-emitting TADF compounds, which were designed by considering both H-bonding and sterically controlled charge-transfer (CT) interactions between D and A units. Methyl substitution employed at the 1st position of t-butyl-carbazole donors was found to affect CT strength and consequently TADF properties of the studied compounds enabling significant reduction of delayed fluorescence lifetime (down to 3.1 μs) and enhancement of reverse intersystem crossing rate (up to 106 s-1). The naphthyridines were demonstrated to hold great potential for deep-blue TADF emitters suitable for both vacuum- and solution-processed TADF OLEDs. The optimized devices with 7 wt% of naphthyridine emitter in weakly polar mCP host delivered external quantum efficiencies (EQEs) of up to ~17.6% and ~13.5% for vacuum- and solution-processed OLEDs, respectively. Unsubstituted naphthyridine exhibited deep-blue (λmax < 460 nm) and narrow-band (FWHM = 66 nm) electroluminescence, whereas more twisted methyl-substituted compound expressed broader band (FWHM >80 nm) sky-blue (λmax ? 480 nm) emission. The demonstrated emitters are among the best-performing conventional D-A-type blue/deep-blue TADF emitters in terms of EQE and efficiency roll-off properties of their devices.
关键词： H-bonding,carbazole,deep-blue,charge-transfer,OLED,TADF,naphthyridine
更新于2025-09-23 15:21:01
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Novel adamantane-bridged phenanthroimidazole molecule for highly efficient full-color organic light-emitting diodes
摘要： Highly efficient deep blue phenanthroimidazole fluorescent material by incorporating an adamantane moiety (AD-BPI) is designed and synthesized. AD-BPI exhibits excellent photophysical properties including a deep blue emission, high triplet energy level and photoluminescence efficiency, fine morphological and thermal stability, and ambipolar nature. Non-doped deep blue organic light-emitting diodes (OLEDs) following the construction of ITO (Indium–Tin Oxide)/TAPC (Bis [4-[N, N-di (4-tolyl) amino] phenyl]-cyclohexane, 30 nm)/AD-BPI (100 nm)/TPBi (1, 3, 5-tris (2-N-phenylbenzimidazolyl) benzene, 50 nm)/Liq (8-hydroxyquinolatolithium, 2 nm)/Al (100 nm) utilizing AD-BPI as emissive layer achieve the peak external quantum efficiency (EQE) of 5.8% with the CIE coordinates of (0.15, 0.07). Using AD-BPI as universal host, the corresponding green, yellow and red phosphorescent devices are also fabricated and exhibit the maximum EQEs of 23.3%, 16.7% and 19.1% accompanying with negligible efficiency roll-off under ultrahigh luminance. These experimental performances are intensely competitive with the recently reported advanced results of full-color OLEDs. It is the first demonstration of adamantane-based phenanthroimidazole molecule featuring as both host and emitter.
关键词： Adamantane,Host,Deep blue,OLEDs,Phenanthroimidazole
更新于2025-09-23 15:19:57
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Imidazo[1,2-a]pyridine as an electron acceptor to construct?? high-performance deep-blue organic light-emitting diodes with negligible efficiency roll-off
摘要： Two novel bipolar deep-blue fluorescent emitters, IP-PPI and IP-DPPI featuring different lengths of phenyl bridge, were designed and synthesized, in which imidazo[1,2-a]pyridine (IP) and phenanthroimidazole (PI) were proposed as an electron-acceptor and an electron donor respectively. Both of them exhibited outstanding thermal stability and high emission quantum yield. All the devices based on these two materials showed negligible efficiency roll-off with increasing current density. Impressively, non-doped organic light-emitting diodes (OLEDs) based on IP-PPI and IP-DPPI exhibited EQE of 4.85% and 4.74% with CIE coordinates of (0.153, 0.097) and (0.154, 0.114) at 10000 cd m-2, respectively. Besides, the 40 wt% IP-PPI doped device maintained high EQE of 5.23% with CIE coordinates of (0.154, 0.077) at 10000 cd m-2. The doped device based on 20 wt% IP-DPPI exhibited higher deep-blue electroluminescence (EL) performance with maximum EQE up to 6.13% at CIE of (0.153, 0.078) and remained EQE of 5.07% at 10000 cd m-2. To the best of our knowledge, these performances are among the state-of-the art devices with CIEy ≤ 0.08 at a high brightness of 10000 cd m-2. Furthermore, by doping a red phosphorescent dye Ir(MDQ)2 into IP-PPI and IP-DPPI hosts, high-performance red PhOLEDs with EQE of 20.8% and 19.1% were achieved, respectively. This work may provide a new approach for designing highly efficient deep-blue emitters with negligible roll-off for OLED applications.
关键词： negligible efficiency roll-off,imidazo[1,2-a]pyridine,OLEDs,deep-blue
更新于2025-09-23 15:19:57
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Tetraphenylbenzene-based AIEgens: horizontally oriented emitters for highly efficient non-doped deep blue OLEDs and hosts for high-performance hybrid WOLEDs
摘要： Deep blue organic-emitting fluorophores are crucial for applications in white lighting and full color flat-panel displays but emitters with high color quality and efficiency are rare. Herein, novel tetraphenylbenzene (TPB) based deep blue AIE luminogens (AIEgens) with various donor units and an acceptor of cyano groups are developed and used to fabricate non-doped deep blue and hybrid white organic light-emitting diodes (OLEDs). Benefiting from its high emission efficiency and high proportion of horizontally oriented dipoles in the film state, the non-doped deep blue device based on CN-TPB-TPA realizes a maximum external quantum efficiency 7.27%, with a low efficiency roll-off and CIE coordinates of (0.15, 0.08). Moreover, efficient two-color hybrid warm white OLEDs (CIEx,y = 0.43, 0.45) are achieved using CN-TPB-TPA as the blue-emitting layer and phosphor doped host, which realized maximum current, power, external quantum efficiencies of 58.0 cd A-1, 60.7 lm W-1 and 19.1%, respectively. This work provides a general strategy to achieve high performance, stable deep blue and hybrid white OLEDs by construction of AIEgens with excellent horizontal orientation.
关键词： AIEgens,horizontal orientation,hybrid WOLEDs,Deep blue,OLEDs
更新于2025-09-23 15:19:57
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Novel 9,9-dimethylfluorene-bridged D–π–A-type fluorophores with a hybridized local and charge-transfer excited state for deep-blue electroluminescence with CIE <sub/>y</sub> ～ 0.05
摘要： Deep-blue light emitting materials are of great significance in the fields of commercial full-color organic light-emitting diodes (OLEDs) and solid-state lighting. The hybridized local and charge-transfer excited state (HLCT) is a promising strategy to achieve deep-blue emission and high photoluminescence quantum yield. Based on HLCT, we designed and synthesized two novel donor–π–acceptor, 9,9-dimethylfluorene-bridged fluorophores (DFPBI & TFPBI) for efficient deep-blue OLED applications. Non-doped devices, with DFPBI and TFPBI as emitters, exhibit deep-blue emission with CIE coordinates of (0.154,0.042) and (0.152,0.054), accompanied by good EL performance with maximum external quantum efficiencies (EQEs) of 4.18% and 5.74%, respectively. In particular, the TFPBI-based non-doped device displays a slow efficiency roll-off at high luminance with an EQE of 5.50% and 4.80% at 100 cd m?2 and 1000 cd m?2, respectively. This work not only demonstrates the potential of these two fluorophores in deep-blue OLEDs, but also provides tactics for the design of deep-blue light emitting materials by using the 9,9-dimethylfluorene-bridged D–π–A architecture.
关键词： 9-dimethylfluorene,9,fluorophores,deep-blue emission,HLCT,OLEDs
更新于2025-09-19 17:15:36
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The Structure Optimization of Phenanthroimidazole Based Isomers with External Quantum Efficiency Approaching 7% in non-doped Blue OLEDs
摘要： In this work, four phenantroimidazole (PI) based isomers TPA-PPI-PBI, TPA-PPI-NPBI, PBI-PPI-TPA and NPBI-PPI-TPA for high-efficiency deep-blue organic light-emitting diodes (OLEDs) have been designed and synthesized. The structure-property relationship is systematically studied. Devices based on TPA-PPI-PBI, TPA-PPI-NPBI, PBI-PPI-TPA and NPBI-PPI-TPA achieved deep-blue emissions with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.15, 0.07), (0.15, 0.07), (0.15, 0.09) and (0.15, 0.05) and high external quantum efficiencies (EQEmax) of 4.12%, 4.66%, 6.88% and 5.59%, respectively. Especially the PBI-PPI-TPA based device exhibited negligible efficiency roll-off with EQE 6.48% at practical 1000 cd m-2. Moreover, the EQE is still above 5% even at a high brightness of 10,000 cd m-2. Comparing the four isomers, we found that substituent at the C2 position of PI core has a significant influence on the emission wavelength and CIE coordinates. This work provides a rational design strategy that modifying electron acceptor (A) at the C2 position and electron donor (D) at the N1 position of PI core will be an effective way to fabricate high-performance PI-based bipolar emitters.
关键词： deep-blue,isomers,phenanthroimidazole,external quantum efficiency,OLEDs
更新于2025-09-19 17:13:59
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Asymmetric anthracene derivatives as multifunctional electronic materials for constructing simplified and efficient non-doped homogeneous deep blue fluorescent OLEDs
摘要： Herein, large π-conjugated core anthracene with an innate bipolar property was employed to construct multifunctional organic electronic materials. Delicate manipulating molecules via combining anthracene core and large periphery groups, two asymmetric anthracene derivatives namely (4-(10-(4-(9H-1,5-diazacarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (p-PO15NCzDPA) and (3-(10-(3-(9H-1,5-diazarcarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (m-PO15NCzDPA) were firstly designed and developed. The large periphery groups 1,5-diazarcarbazole (15NCz) and diphenylphosphine oxide (PO) efficiently interrupt the intramolecular π-conjugation, presenting an asymmetric bulky periphery enveloping strategy achieving highly twisted structures, which help to realize deep-blue emission. Meanwhile, due to the high PLQY and well-balanced bipolar transport characteristics, desired device addressing the contradiction of efficiency, color gamut and structure complexity is within reach. Detailed device engineering study was carried out, in which p-PO15NCzDPA and m-PO15NCzDPA were functioned as multifunction layers. As expected, p-PO15NCzDPA-based homogenous and unilateral homogenous OLEDs exhibited outstanding performance with impressive EQEmax of 4.55% and 6.40%, deep blue CIE coordinates of (0.152, 0.075) and (0.151, 0.066) at the voltage of 6 V, narrow FWHM of 46 nm and 50 nm, respectively. More importantly, the simplified homogenous device achieved extremely low efficiency roll-offs of 1.3% and 4.8% at 1000 and 5000 cd m-2, respectively. These results are among the most outstanding performance, which provided a guide for further improving the performance of deep blue fluorescent OLEDs and simplifying the structure of OLEDs.
关键词： asymmetric anthracene derivatives,homogenous device structure,multifunctional materials,deep-blue emission,fluorescent OLEDs
更新于2025-09-19 17:13:59
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Nanosecond-time-scale delayed fluorescence molecule for deep-blue OLEDs with small efficiency rolloff
摘要： Aromatic organic deep-blue emitters that exhibit thermally activated delayed fluorescence (TADF) can harvest all excitons in electrically generated singlets and triplets as light emission. However, blue TADF emitters generally have long exciton lifetimes, leading to severe efficiency decrease, i.e., rolloff, at high current density and luminance by exciton annihilations in organic light-emitting diodes (OLEDs). Here, we report a deep-blue TADF emitter employing simple molecular design, in which an activation energy as well as spin–orbit coupling between excited states with different spin multiplicities, were simultaneously controlled. An extremely fast exciton lifetime of 750 ns was realized in a donor–acceptor-type molecular structure without heavy metal elements. An OLED utilizing this TADF emitter displayed deep-blue electroluminescence (EL) with CIE chromaticity coordinates of (0.14, 0.18) and a high maximum EL quantum efficiency of 20.7%. Further, the high maximum efficiency were retained to be 20.2% and 17.4% even at high luminance.
关键词： deep-blue OLEDs,organic light-emitting diodes (OLEDs),small efficiency rolloff,Nanosecond-time-scale delayed fluorescence,thermally activated delayed fluorescence (TADF)
更新于2025-09-19 17:13:59