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Non-doped phosphorescent organic light-emitting devices with an exciplex forming planar structure for efficiency enhancement
摘要： Organic light-emitting devices (OLEDs) consisting of a non-doped phosphorescent dye that inserted in an exciplex forming planar structure have been fabricated, and the thickness of ultrathin phosphor layer is optimized to achieve high efficiency. The results showed that OLEDs based on the exciplex interface and a 0.5 nm thick phosphorescent dye have a power efficiency, a current efficiency, and an external quantum efficiency of 37.4 lm/W, 40.5 cd/A, and 14.3%, respectively, which are almost two-folds higher than those with non-exciplex interface devices. Meanwhile, the efficiency roll-off is significantly suppressed. These improved device performances are attributed to the elimination of triplet energy leakage from exciplexes to constituting molecules, efficient energy up conversion of triplet exciplexes and complete host-guest F?rster energy transfer. These results will provide an easily-fabricated and time-saving approach for high-performance OLEDs.
关键词： non-doped,planar structure,Organic light-emitting device (OLED),exciplex,phosphorescent dye
更新于2025-09-23 15:22:29
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A Novel Series of Thermally and Electrically Stable Hole-Transporters End-Capped by [1]Benzothieno[3,2- <i>b</i> ][1]benzotiophenes for Organic Light-Emitting Devices
摘要： A novel series of hole-transporters for organic light-emitting devices (OLEDs) was developed with the aim of high thermal and electrical stability. This was achieved by introducing [1]benzothieno[3,2-b][1]benzothiophene (BTBT) moieties as end-cap groups. These BTBT-end-capped hole-transporters exhibited superior thermal stability with a glass transition temperature (Tg) of over 150 °C and high electrical stability in green phosphorescent OLEDs at a high brightness of over 8000 cd m–2 (current density: 15 mA cm–2).
关键词： Organic light-emitting device (OLED),Hole-transporter,Arylamine derivative
更新于2025-09-23 15:22:29
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Holographic Fabrication and Optical Property of Graded Photonic Super-Crystals with a Rectangular Unit Super-Cell
摘要： Recently developed graded photonic super-crystals show an enhanced light absorption and light extraction efficiency if they are integrated with a solar cell and an organic light emitting device, respectively. In this paper, we present the holographic fabrication of a graded photonic super-crystal with a rectangular unit super-cell. The spatial light modulator-based pixel-by-pixel phase engineering of the incident laser beam provides a high resolution phase pattern for interference lithography. This also provides a flexible design for the graded photonic super-crystals with a different ratio of length over the width of the rectangular unit super-cell. The light extraction efficiency is simulated for the organic light emitting device, where the cathode is patterned with the graded photonic super-crystal. The high extraction efficiency is maintained for different exposure thresholds during the interference lithography. The desired polarization effects are observed for certain exposure thresholds. The extraction efficiency reaches as high as 75% in the glass substrate.
关键词： spatial light modulator,holographic lithography,organic light emitting device,photonic crystals,graded photonic super-crystals,extraction efficiency
更新于2025-09-23 15:21:01
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Low color temperature, high color rendering index candlelight style white organic light-emitting devices with a fac-tris (mesityl-2-phenyl-1H-imidazole) iridium (III) blue emitting layer
摘要： Blue phosphorescent organic light-emitting devices based on fac-tris (mesityl-2-phenyl-1H-imidazole) iridium (III) (fac-Ir(mpim)3) doped in different host materials are fabricated. The device with a 2,6-bis(3-(carbazol-9-yl)phenyl)pyridine host shows an excellent performance. Based on this blue emitting device, white organic light-emitting devices with high performance are achieved. The optimized device shows a color rendering index of 92 and a color temperature of 2572 K, which are comparable to the incandescent bulb. Besides, it also presents a high current ef?ciency of 23.1 cd A ?1 at brightness of 1000 cd m and a power ef?ciency of 15.8 lm W organic light-emitting device has the potential as a comfortable lighting source.
关键词： candlelight style white organic light-emitting device,CCT,CRI
更新于2025-09-23 15:21:01
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Manipulating charge carrier transporting of disubstituted phenylbenzoimidazole-based host materials for efficient full-color PhOLEDs
摘要： Many efforts have been focused on exploring highly efficient host materials that capable of function in phosphorescent organic light-emitting devices (PhOLEDs). However, superior hosts reported to date that are generally suitable to full-color devices are rare and the resultant device performances are far from satisfactory. A class of host compounds DCzPBI, POCzPBI, and DPOPBI, incorporating carbazole and diphenylphosphoryl oxide moieties as electron-donating and -accepting groups, respectively, are synthesized and successfully applied as universal hosts in the fabrication of full-color PhOLEDs. The effect of substituted groups on the photophysical, theoretical calculations, and electrochemical characters for host materials is systematically investigated. We adopt the same device architecture to fabricate the blue, green, yellow, and red PhOLEDs with the combination of the three hosts. As a result, DPOPBI and POCzPBI with good charge carrier transporting properties supported the devices with the impressive efficiencies. The best current efficiency (CE) are 23.2, 48.4, 45.7, 21.5 cd A?1 for blue, green, yellow, and red devices, respectively. Even at the brightnesses of 1000 cd m?2, the efficiency roll-offs are only 2% for green and 0.2% for yellow devices, indicating the promising applications as universal hosts for highly efficient PhOLEDs.
关键词： impressive efficiency,phosphorescent organic light-emitting device,good charge carrier transporting property,host material
更新于2025-09-11 14:15:04
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Vacuum Annealing of White-Light Organic Light-Emitting Devices with Polyfluorene Copolymer as Light-Emitting Layer
摘要： White-light organic light-emitting devices (OLEDs) were fabricated, in which poly(9,9-dioctyl)fluorene with insertion of 4,7-bithienyl-2,1,3-benzothiadiazole (PFO-DBT5) were utilized as light-emitting layer. During fabrication of white-light OLED, PFO-DBT5 films were vacuum annealed under four different temperatures, respectively. Then, the relationship between vacuum annealing of PFO-DBT5 films and performance of white-light organic light-emitting device was studied by atomic force microscope observation and electroluminescence properties characterization. It was concluded that degree of stacking order and the inter-chain distance and of PFO-DBT chains influence device performance directly; the optimal vacuum annealing temperature was gained to be 100 oC by comparison experiments.
关键词： White-light,F?rster,Organic light-emitting device,Annealing
更新于2025-09-09 09:28:46
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Highly Efficient Fluorescent Organic Light-Emitting Devices Using a Luminescent Radical as the Sensitizer
摘要： In traditional fluorescent organic light-emitting diodes (OLEDs), the upper limit of internal quantum efficiency (IQE) is only 25% because 75 % triplet excitons created on the fluorescent dyes are non-luminous. Here, luminescent radicals are proposed as the sensitizer. Under ideal conditions, electrons and holes firstly recombine on the sensitizer molecule to create doublet excitons, then through energy transfer to generate singlet excitons on the fluorescent dye, finally via radiative decay to emit light. The upper limit of IQE can theoretically reach 100%. As an example, the maximum external quantum efficiency (EQE) of a fluorescent OLED sensitized by a luminescent radical, TTM-1Cz, has reached 8.1%, which is much higher than the upper limit of EQE of traditional fluorensenct OLEDs. Our results suggest a new route to realize highly efficient fluorescent OLEDs.
关键词： organic light-emitting device,doublet,luminescent radical,sensitize,deep-red
更新于2025-09-04 15:30:14