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Rational Design of Axially Chiral Platinabinaphthalenes with Aggregation-Induced Emission for Red Circularly Polarized Phosphorescent Organic Light-Emitting Diodes
摘要： Circly polarized luminescent (CPL) materials have received great interest due to their potential applications in next-generation displays. However, the development of easily accessible red circularly polarized phosphorescent emitters for practical organic light-emitting diodes fabrication remains a grand challenge. In this paper, we report a new family of CPL-active platinum complexes based on the binaphthalene chiral platform. These axially chiral platinabinaphthalenes were facile synthesized by directly incorporating platinum(II) into the π-conjugated backbone of commercially available enantiopure binaphthalene derivate. These complexes exhibit aggregation-induced circularly polarized phosphorescence enhancement with high quantum yields up to 66% and luminescence dissymmetry factors around 2.6×10?3. Moreover, solution-processable circularly polarized organic light-emitting diodes (CPOLEDs) using these complexes as emitters show good performance with the maximum luminance up to 3500 cd m2 and dissymmetry factor values around 1.0×10?3. These findings by rational design of axially chiral platinabinaphthalenes are important for the development of high-performance CPL complexes for CPOLEDs.
关键词： circularly polarized luminescence,binaphthalene,organic light-emitting diode,platinum complex,aggregation-induced emission
更新于2025-09-16 10:30:52
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Highly Efficient Solution-Processed TADF Bluish-Green and Hybrid White Organic Light-Emitting Diodes Using Novel Bipolar Host Materials
摘要： Two pyridine containing bipolar host materials with high triplet energy, 9,10-dihydro-9,9-dimethyl-10-(3-(6-(3-(9,9-dimethylacridin-10(9H)-yl)phenyl)pyridin-2-yl)phenyl acridin (DDMACPy) and N-(3-(6-(3-(diphenylamino)phenyl)pyridin-2-yl)phenyl)-N-phenylbenzenamine (DTPAPy), are synthesized from modifying the commonly adapted host material 2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyridine (DCzPPy). The HOMO levels of DDMACPy (5.50 eV) and DTPAPy (5.60 eV) are found to be shallower than that of DCzPPy (5.90 eV) that leads to the improvement in hole injection from the hole transport layer PEDOT:PSS (WF = 5.10 eV). These host materials are used in the emitting layer of bluish-green organic light-emitting diode (OLED) with the TADF emitter, 9,9-dimethyl-9,10-dihydroacridine-2,4,6-triphenyl-1,3,5-triazine (DAMC-TRZ), as the guest. The DDMACPy-based device shows the highest performance among them with the maximum external quantum efficiency (EQEmax), current efficiency (CEmax) and power efficiency (PEmax) of 21.0%, 53.1 cd A-1 and 44.0 lm w-1 at CIE (0.17, 0.42), respectively. By further doping with the red emitting phosphor iridium(III) bis(2-phenylquinoline)(2,2,6,6-tetramethylheptane-3,5-ionate) [Ir(dpm)PQ2] and yellow emitting phosphor iridium(III) bis(4-(4-t-butyphenyl) thieno[3,2-c]pyridinato-N,C20)acetylacetonate (PO-01-TB) emitters into the bluish-green emitting layer, a TADF-phosphor hybrid white OLED (T-P WOLED) is obtained with excellent EQEmax, CEmax and PEmax of 17.4%, 48.7 cd A-1 and 44.5 lm w-1 at CIE (0.35, 0.44), respectively. Moreover, both the bluish-green and white OLED show the low efficiency roll-off with external quantum efficiencies at the brightness of 1000 cd m-2 (EQE1000) 18.7% and 16.2% respectively, and are the highest performance records among the solution-processed TADF bluish-green and T-P WOLEDs.
关键词： low efficiency roll-off,solution process,bipolar host material,TADF bluish-green organic light-emitting diode,hybrid white organic light emitting diode
更新于2025-09-12 10:27:22
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A Temperature Compensation Method by Adjusting Gamma Voltages for High Luminance Uniformity of Active Matrix Organic Light-Emitting Diode Displays
摘要： In this paper, a temperature compensation method is proposed for active-matrix organic light-emitting diode (AMOLED) displays to achieve high luminance uniformity over a wide operating temperature range. The proposed temperature compensation method compensates for variation in OLED luminance according to temperature by adjusting the gamma voltages. To verify the proposed method, a built-in test circuit, which includes temperature sensors, current calculation block, current adjustment block, and gamma voltage generator, was fabricated using 90 nm complementary metal-oxide semiconductor process technology with 6 V high-voltage devices. The measurement results show that the proposed method achieves a high luminance uniformity with an OLED luminance variation of less than 1.54 cd/m2 over the temperature range of –45°C to 60°C. Therefore, the proposed temperature compensation method is suitable for AMOLED displays requiring high luminance uniformity.
关键词： gamma voltage,high luminance uniformity,temperature compensation,Organic light-emitting diode (OLED)
更新于2025-09-12 10:27:22
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Facile structure-modification of xanthenone based OLED emitters exhibiting both aggregation induced emission enhancement and thermally activated delayed fluorescence
摘要： Four new donor-acceptor compounds were designed, synthesized and investigated by theoretical and experimental approaches aiming to estimate effect of the structure of a donor on the properties of potential OLED emitters. Because of the different electron-donating abilities of the nitrogen-containing heterocycles, derivatives of xanthenone containing di-tert-butyl-carbazolyl, di-tert-butyl-acridanyl, di-tert-butyl-phenothiazinyl and penoxazinyl moieties exhibited different photophysical behavior. Because of big dihedral angles between the donors and acceptor as well as because of possibility of rotation around N-C bond, the designed compounds were characterized by thermally activated delayed fluorescence and aggregation induced emission enhancement effect. Twice higher photoluminesce quantum yields reaching 38% in doped films were obtained for compounds containing di-tert-butyl-carbazolyl and di-tert-butyl-acridanyl moieties as compared to those observed for compounds with the donors containing S and O heteroatoms. Strong effect of the donor substituents on charge injection (ionization potentials were in the range of 5.67-5.96 eV) and charge-transporting properties (hole and electron mobilities were in a wide range from 6.3×10-8 to 6.3×10-4 cm2V-1s-1 at electric field of 2.5×105 V·cm-1) was detected. The differently substituted compounds were utilized as emitters in OLEDs. Higher maximum values of external quantum efficiency (up to 3.5%) were observed for OLEDs based on emitters with nitrogen containing donors relative to estimated for OLEDs based on emitters containing di-tert-butyl-phenothiazinyl and penoxazinyl moieties.
关键词： aggregation induced emission enhancement,xanthenone,Organic light-emitting diode,thermally activated delayed fluorescence
更新于2025-09-12 10:27:22
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Simulation of Multilayer Energy Efficient OLEDs for Flexible Electronics Applications
摘要： Organic light emitting (OLEDs) work on electro luminescence principles and these OLEDs are commercially available and can be used in display because of the low power consumption. Proposed research deals with the design of high-efficiency OLEDs, including electrical and optical design of OLEDs. The Luminescent efficiency of bilayer and Triple layer OLED experiment and analysis was done using the Silvaco TCAD tool in this research work. The simulation of electronics and optical features such luminescence power versus anode voltage, anode voltage versus anode current characteristics and exciton state of both bilayer and Triple layer OLEDs were discussed. The physical design, processes as well as principles of OLED has been discussed and operational distribution of Langevin recombination inside proposed structures were acquired and discussed.
关键词： Efficiency Improvement,Organic Light emitting diode (OLEDs),Multilayer,TCAD
更新于2025-09-12 10:27:22
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Phthalonitrile-based bipolar host for efficient green to red phosphorescent and TADF OLEDs
摘要： A bipolar host material named 4-(9H-carbazol-9-yl)phthalonitrile (CzPN) was developed by combining carbazole and phthalonitrile as donor and acceptor units, respectively. The introduction of the phthalonitrile unit realized a relatively small energy gap of 3.00 eV as well as a deep lowest unoccupied molecular orbital level of ?2.72 eV. The characterization of carrier-only devices demonstrated the bipolar charge transporting property of CzPN. With a triplet energy of 2.70 eV, CzPN was investigated as host in green, yellow, and red phosphorescent organic light-emitting diodes (PhOLEDs) and green thermally activated delayed fluorescence (TADF) devices. A low turn-on voltage of 2.8 V was achieved by all the four diodes. Both PhOLEDs and TADF devices exhibited high external quantum efficiency values over 20% with relatively small efficiency roll-offs. These findings demonstrate that CzPN is an excellent host material for both phosphorescent and TADF emitters, and phthalonitrile is a promising unit to develop universal host materials.
关键词： Phthalonitrile,Bipolar host,Phosphorescent organic light-emitting diode,Thermally activated delayed fluorescence
更新于2025-09-12 10:27:22
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38.1: Quantitative Analysis of Charge Transport in Single‐Carrier Devices and OLEDs Combining DC and AC Data
摘要： Single-carrier devices are perfect model systems to extract material parameters for more complex multilayer organic light-emitting diodes (OLEDs) and to learn about charge transport and injection properties of the device. By combining simulation and measurements in steady-state and frequency domain, we obtain a set of reliable material parameters which can be used to model the multilayer OLED structure. Moreover, we can also evaluate the contact behavior and conclude that the OLED operation is limited by electron transport.
关键词： characterization,organic light-emitting diode,mobility,material parameter,doping
更新于2025-09-12 10:27:22
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Low-Bandgap Polymer-based Infrared-to-Visible Up-Conversion Organic Light-Emitting Diodes with Infrared Sensitivity up to 1.1μm
摘要： All-organic infrared (IR)-to-visible up-conversion organic light-emitting diodes (OLEDs) with an IR sensitivity up to 1,100nm were fabricated using a low bandgap polymer as the organic IR sensitizing layer. A novel low bandgap (1 eV) polymer, poly 4-(4,8-bis(5-(2-butyloctyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophen-2-yl)-6,7-diethyl-[1,2,5] thiadiazolo[3,4-g]quinoxaline (PBDTT-BTQ), with a strong photo-response in near-IR wavelengths of 700-1,100nm was first synthesized using a thiadiazolo[3,4]quinoxaline (BTQ) and a thiophene-substituted benzo[1,2-b:4,5-b2-bdithiophene (BDTT) as the electron-withdrawing and donating building blocks, respectively. The near-IR photodetector was then fabricated for evaluating a PBDTT-BTQ as the IR sensitizing layer. The PBDTT-BTQ IR photodetector showed detectivity greater than 1011 Jones in multi-spectral region (300-1,100nm) and the maximum detectivity of 3.1× 1011 Jones at the wavelength of 1,000nm due to significantly reducing dark current (8.8 × 10-6 mA/cm2 at -1 V). Finally, the all-organic IR up-conversion OLED with a PBDTT-BTQ IR sensitizer successfully converted invisible near-IR light of 700nm-1,100nm directly to visible green light with a peak emission wavelength of 520nm. This is the first report of all-organic IR-to-visible up-conversion OLED with near-IR sensitivity up to 1,100nm.
关键词： Organic Light Emitting Diode,Low Bandgap Polymer,Up-Conversion,Near-Infrared
更新于2025-09-12 10:27:22
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Benzoylpyridine-based TADF emitters with AIE feature for efficient non-doped OLEDs by both evaporation and solution process
摘要： Fluorescent materials taking both advantages of evaporation and solution processes are urgently explored for the development of efficient and simplified organic light-emitting diodes (OLEDs). Furthermore, it is another huge challenge for such materials to achieve excellent electroluminescence performances in non-doped OLEDs. Herein, two new emitters, named as PyB-DPAC and PyB-DMAC with 4-benzoylpyridine moiety as the electron acceptor and 9,9-diphenyl-9,10-dihydroacridine or 9,9-dimethyl-9,10-dihydroacridineas the electron donor were synthesized and explored. Both emitters exhibit distinct TADF character, typical AIE feature and relatively high photoluminescence quantum yields. Accordingly, we demonstrated efficient non-doped vacuum-deposited OLED based on the PyB-DPAC with a maximum external quantum efficiency (EQE) up to 9.7%, and meanwhile an extremely low efficiency roll-off of 1.7% at a high brightness of 1000 cd m-2. In addition, an impressive EQE of 11.1% can be realized from the solution-processed non-doped devices with the using of PyB-DPAC emitter. These affirmative results manifest that TADF emitters incorporate with the benzoylpyridine acceptor enabling a promising molecular design strategy in adapt to the non-doped evaporation- and solution-processed highly efficient OLEDs.
关键词： benzoylpyridine,Organic light-emitting diode,thermally activated delayed fluorescence,aggregation-induced emission
更新于2025-09-12 10:27:22
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[IEEE 2019 International conference on Creative Business for Smart and Sustainable Growth (CREBUS) - Sandanski, Bulgaria (2019.3.18-2019.3.21)] 2019 International Conference on Creative Business for Smart and Sustainable Growth (CREBUS) - Innovative LED Lighting
摘要： The main innovative technologies and the principle of operation of OLED, FOLED, PHOLED, TOLED, QLED and RGB diodes are examined in this work. Luminous efficiency and the operating time dependencies on the working temperature of the diode are presented. The highly efficient light sources presented are also considered from the point of view of their energy use: for their production, use and subsequent safe disposal. In this way, an economic and environmental assessment of the benefits of their use in industry and households has been made.
关键词： Light-Emitting Diode,Efficiency,Quantum dot light emitting diode,Organic Light Emitting Diode
更新于2025-09-11 14:15:04