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oe1(光电查) - 科学论文

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  • Sol-gel processed vanadium oxide as efficient hole injection layer in visible and ultraviolet organic light-emitting diodes

    摘要： Low-cost, high-throughput and scalable production currently boosts organic electronic device towards solution processing. Sol-gel processed aqueous vanadium oxide (h-VOx) is facilely synthesized and proven to be efficient hole injection layer (HIL) in visible and ultraviolet organic light-emitting diodes (OLEDs). Atomic force microscopy and X-ray/ultraviolet photoelectron spectroscopy measurements indicate that h-VOx behaves superior film morphology and exceptional electronic properties such as oxygen vacancy dominated non-stoichiometry and appropriate surface work function. With tris(8-hydroxy-quinolinato)aluminium as emitter, the visible OLED gives maximum luminous and power efficiencies of 6.3 cd/A and 3.2 lm/W, respectively, which are slightly superior to the counterpart with vacuum thermally-evaporated VOx (5.6 cd/A and 2.7 lm/W). With 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole as emitter, the ultraviolet OLED produces attractive short-wavelength emission of 379 nm with full width at half maximum of 40 nm and improved durability. The maximum radiance and external quantum efficiency reach 15.3 mW/cm2 and 2.92%, respectively, which are considerably enhanced in comparison with the corresponding reference (11.9 mW/cm2 and 2.32%). Current versus voltage characteristics and impedance spectroscopy analysis elucidate that h-VOx exhibits robust hole injection and accordingly high-performance OLEDs. Our results pave an alternative way for advancing organic electronic devices and VOx applications with solution process.

    关键词： Organic light-emitting diode,Hole injection,Solution process,Vanadium oxide,Sol-gel method

    更新于2025-11-20 15:33:11

  • Single crystal structure and electroluminescence efficiency of blue fluorescence OLED emitters using triple core chromophores

    摘要： The relationship between the single crystal structure of materials and the EL performance of doped OLED devices was investigated. The 1,6-bis-(10-[1,1′;3′,1″]terphenyl-5′-yl-anthracen-9- yl)-pyrene (1,6 DAP-TP) has a dihedral angle (α) of 78.4 ° and a dihedral angle (β) of 81.2 °, a relatively more twisted single crystal structure compared to that of 6,12-bis-(10- [1,1′;3′,1″]terphenyl-5′-yl-anthracen-9-yl)-chrysene (DAC-TP). Such a highly twisted molecular structure can improve the electroluminescence (EL) efficiency of a material because it can inhibit rotational and vibrational motions. Also, since the doped state and single crystal structure imply, respectively, a diluted state and a molecular state, the EL efficiency of the doped OLED device is related to single crystal structure. In a 4% doped OLED device, 1,6 DAP-TP and DAC- TP showed CE of 2.10 cd A-1 and 0.93 cd A-1, respectively. With its relatively more twisted single crystal structure, 1,6 DAP-TP showed higher CE in a doped OLED device than DAC-TP. Both compounds had ultra-deep blue emission y values of 0.06 or less for the color coordinates, which satisfy high density television display requirements (y value less than 0.08).

    关键词： Organic light-emitting diode,single crystal,fluorescence,dopant,blue

    更新于2025-10-22 19:40:53

  • Enhancing Reverse Intersystem Crossing via Secondary Acceptors: towards Sky-Blue Fluorescent Diodes with Tenfold-Improved Exter-nal Quantum Efficiency

    摘要： How to simply but effectively facilitate reverse intersystem crossing (RISC) transition is always the key issue for developing high-performance thermally activated delayed fluorescence (TADF) dyes. In this work, as a proof of concept, a feasible strategy named 'acceptor enhancement' is demonstrated with a series of ternary blue emitters (xCzmPOnTPTZ) using diphenylphosphine oxide (PO) as secondary acceptors. Compared with its PO-free binary analogue, such simple introduction of PO groups in pCzPO2TPTZ dramatically enhances its RISC rate constant (kRISC) by 10 times to the level of ~105 s-1, accompanied by RISC efficiency (ηRISC) of 92%, which further improves the triplet-to-singlet upconversion for effective triplet harvesting in its devices. As the result, on the basis of a trilayer device structure, pCzPO2TPTZ realized a state-of-the-art external quantum efficiency (EQE) beyond 20% with tenfold improvement.

    关键词： Organic Light-Emitting Diode,Thermally Activated Delayed Fluorescence,Excited State Transition,Blue Emission,Reverse Intersystem Crossing,Phosphine Oxide Acceptor

    更新于2025-09-23 15:23:52

  • [IEEE 2018 IEEE Life Sciences Conference (LSC) - Montreal, QC, Canada (2018.10.28-2018.10.30)] 2018 IEEE Life Sciences Conference (LSC) - Design, Implementation, and Test of an Adiabatic Stimulation Back-End for Implantable Optical Stimulation Microsystems

    摘要： This paper introduces a new circuit-level idea for driving optrodes in an optical stimulation system. Trying to make the stimulation circuitry energy efficient, the proposed idea is based on the basic concept of adiabatic circuits. Based on the idea proposed in this paper, a prototype stimulation circuit was developed and tested. The optical stimulation back-end also includes a micro-fabricated optrode array, specifically designed, developed, and tested for multi-channel optical stimulation in a semi-implantable optogenetic system.

    关键词： optrode,optical stimulation,organic light-emitting diode (OLED),optogenetics,adiabatic circuits,LED driver

    更新于2025-09-23 15:22:29

  • Exploiting lateral current flow due to doped layers in semiconductor devices having crossbar electrodes

    摘要： Organic electronic devices such as light-emitting diodes, solar cells or rectifying diodes normally have a sandwich layer architecture stacked between the electrodes in a crossbar layout. Often however, the side effects of operating the devices in such an arrangement are either ignored or give rise to misinterpretations regarding the device performance or layer quality. For the sake of simplicity, device currents are typically assumed to exclusively flow in the direction vertical to the substrate, even though the conductivity of doped organic layers is high and gives rise to significant lateral current flows. Here, we study the vertical and lateral charge up along the n-doped and the p-doped layers as well as the resulting capacitance increase of charging the intrinsic layer outside the active area. We observe that controlling such lateral charging by structuring the doped layers can reduce the leakage current dramatically. We employ impedance spectroscopy to investigate the lateral charging responsibility for the capacitance increase at low frequencies. Modeling of the devices by a distributed RC circuit model yields information about the thickness, the conductivity, and the corresponding activation energy of both, the n-doped and the p-doped layers, simultaneously. We demonstrate that the capacitive effects from lateral charging can easily be misinterpreted as trap states in capacitance frequency characteristics. However, correct analysis with the proposed model actually yields rich and detailed post-fabrication information which can be utilized in device failure and degradation tests. Moreover, our results will aid the design and characterization of new electronic devices where lateral charge flow is part of the device concept.

    关键词： Parasitic current,Leakage current,Impedance spectroscopy,Crossbar electrodes,Lateral current flow,Organic light-emitting diode,Capacitance,Organic solar cell,Structuring

    更新于2025-09-23 15:21:21

  • Improving performance of thermally activated delayed fluorescence emitter by extending its LUMO distribution; 通过扩展LUMO分布提高热激活延迟荧光材料的性能;

    摘要： An optimized compound 9-(9,9-dimethylacridin-10(9H)-yl)-6H-benzo[c]ch-romen-6-one (MAB) was designed and synthesized based on our previously reported TADF emitter 6-(9,9-dimethylacridin-10(9H)-yl)-3-methyl-1H-isochromen-1-one (MAC) to further improve the performance of thermally activated delayed fluorescence (TADF) emitters. With the additional phenyl in coumarin-contained plane, MAB possesses an extended distribution of the lowest unoccupied molecular orbitals (LUMO), and thus realizes reduced electron exchange between the frontier molecular orbitals and a stretched molecular dipole moment compared with MAC. MAB based organic light-emitting diode (OLED) exhibits a remarkable maximum external quantum efficiency (EQE) of 21.7%, which is much better than the maximum EQE of MAC-based OLED with a value of 12.8%. Our work proves that extending the distribution of LUMO is a simple but effective method to improve the efficiency of TADF emitter.

    关键词： lumo distribution,external quantum efficiency,thermally activated delayed fluorescence,organic light-emitting diode

    更新于2025-09-23 15:21:21

  • Organic Upconversion Display with an over 100% Photon-to-photon Upconversion Efficiency and a Simple Pixelless Device Structure

    摘要： Comparing to traditional near infrared (NIR) imaging devices, NIR-to-visible upconversion display which integrated a NIR photodetector with a visible light-emitting diode have merits of simple device structure, low cost, high resolution, and a simple pixelless structure. However, photon-to-photon upconversion efficiencies of these devices are typically much lower than unity. Here we report an all-organic NIR-to-visible upconversion display with a photon-to-photon upconversion efficiency higher than 100% by integrating a photomultiplying organic NIR photodetector with a high-efficiency thermally activated delayed fluorescent organic light-emitting-diode. To the best of our knowledge, this is the first report showing a photon-to-photon upconversion efficiency over 100% without using a built-in transistor for current amplification.

    关键词： organic photodetector,NIR-to-visible upconversion,photon-to-photon efficiency,thermally activated delayed fluorescence,organic light-emitting diode

    更新于2025-09-23 15:21:01

  • Carbazole-modified polyphenylene ether as host materials for high efficiency phosphorescent organic light-emitting diodes

    摘要： Two novel polymeric hosts called PPO-Cz and PPO-3Cz for solution-processed green phosphorescent organic light-emitting devices have been designed and synthesized by incorporating electron-donor carbazole units with polyphenylene ether. In order to simplify the synthesis route and save cost, we attached the classic carbazole units directly to the side chain of the polyphenylene ether. This molecular design endows these two polymeric hosts with good thermal stability and high triplet energy levels. PPO-Cz- and PPO-3Cz-based emissive-layer green phosphorescent organic light-emitting diodes were fabricated with simplified device configuration by solution-processed using Ir(mppy)3 as a dopant. These devices exhibited lower turn on voltages. Moreover, the PPO-3Cz-based solution processed device showed maximum current efficiency and external quantum efficiency of 31.8 cd/A and 9.3%, respectively. This result demonstrated that the newly synthesized, polymeric hosts were advantageous for fabrication of highly efficient green phosphorescent organic light-emitting diodes.

    关键词： Organic light emitting diode,Polyphenylene ether,Modify,Carbazole,Polymeric host

    更新于2025-09-23 15:21:01

  • An Empirical Study on the Absorption of Carbon Dioxide in OLED-Mixed Concrete through Carbonation Reaction

    摘要： In this study, the ability to absorb CO2 in concrete, in terms of carbonation reaction, was evaluated by utilizing organic light emitting diode (OLED) waste glass as a cementitious binder. The substitution level was set 10%, 20%, and 30% by weight of the binder, and water to binder ratio was kept at 0.4 for all mixes. Prior to estimate the concentration of CO2 uptake, an influence of OLED replacement on pozzolanic reactivity and thus strength development of concrete was investigated. CO2 absorption was calculated by molar concentration of carbonatable phases and carbonation depth derived from quantitative X-ray analysis and accelerating carbonation test, respectively. As a result, the blended concrete exhibits a higher strength with an increase of OLED replacement ratio due to the pozzolanic reaction, compared to the control specimen. Also, the content of CO2 uptake for the mixtures was increased with the substitution level of OLED, of which the OLED-mixed concrete was 1.81- 2.76 times higher than the ordinary Portland cement (OPC) 100% concrete. This behavior may be attributed to an increased rate of carbonation progress. Therefore, it is concluded that the capacity of CO2 absorption is improved by the use of OLED glass powder as a cementitious material in a concrete mixture.

    关键词： Carbonation,Display byproduct,Pozzolanic reaction,Organic light emitting diode,CO2 absorption

    更新于2025-09-23 15:21:01

  • Purine-based thermally activated delayed fluorescence emitters for efficient organic light-emitting diodes

    摘要： Organic fluorescent materials possessing thermally activated delayed fluorescence (TADF) characteristics have attracted tremendous attention. Herein, two TADF emitters (1PXZP and 2PXZP) based on a novel biological base acceptor of 9-methylpurine and commonly used donor of phenoxazine (PXZ) have been successfully synthesized and characterized. Both target compounds possess nearly orthogonal configurations to reduce singlet-triplet splitting energy (ΔEST) for remarkable TADF character. The two emitters show good photoluminescence quantum yields (PLQYs), and thus the organic light-emitting diodes employing 1PXZP and 2PXZP as emitters display good performance with maximum external quantum efficiencies of 10.6% and 13.8%, respectively. The efficiencies of 1PXZP based device show nearly no roll-off at 100 cd m-2 luminance due to the short delayed lifetime (τd) of 3.2 μs. This work manifests that the biological base is a promising acceptor for designing TADF materials.

    关键词： Thermally activated delayed fluorescence,organic light-emitting diode,aggregation-induced emission,purine

    更新于2025-09-23 15:21:01