Synthesis and Electro-Optical Property of Green Fluorescent Emitter Based on Anthracene Core and Optimized Side Groups

New green emitter is designed and synthesized by selecting anthracene having high photoluminescence quantum yield (PLQY) and diphenylamine side group substituted methyl and t-butyl group: N9,N10-bis(5-(tert-butyl)-2-methylphenyl)-N9,N10-bis(2,4-dimethylphenyl)anthracene-9,10-diamine (3Me-1Bu-TPADA). Photophysical, electrochemical, and electroluminescent (EL) properties of 3Me-1Bu-TPADA were investigated. The maximum photoluminescence (PL) emission wavelengths of 3Me-1Bu-TPADA in solution and in a film were 528 nm and 531 nm, respectively. 3Me-1Bu-TPADA has excellent thermal properties with glass transition temperatures (Tg) of 110 °C, melting temperatures (Tm) of 217 °C of, and degradation temperature (Td) of 330 °C. 3Me-1Bu-TPADA was used as an emitting layer in non-doped devices: ITO/2-TNATA (60 nm)/NPB (15 nm)/3Me-1Bu-TPADA (30 nm)/Alq3 (30 nm)/LiF (1 nm)/Al (200 nm). The 3Me-1Bu-TPADA device showed luminance efficiency of 6.05 cd/A, EQE of 2.68% at 10 mA/cm2.

9-(10-phenylanthracen-9-yl)-Benzo[b]Fluoreno[3,4-d] Thiophene Derivatives for Blue Organic Light-Emitting Diodes

In this study, two blue fluorescence materials using phenylanthracene-substituted fluorene derivatives were synthesized and characterized for organic light-emitting diodes (OLEDs). To study their electroluminescent properties, OLED devices were fabricated using these two materials as emissive layer (EML). A device using 7,7-diphenyl-9-(10-phenylanthracen-9-yl)-7H-benzo[b]fluoreno[3,4-d]thiophene in emitting layer showed the highest value of EQE value which is 3.51%. It also showed the luminance efficiency of 3.22 cd/A and power efficiency of 2.89 lm/W with the CIE coordinates (0.15, 0.09).

9-(10-phenylanthracen-9-yl)-7H-Fluoreno[4, 3-b]Benzofuran Derivatives for Blue Organic Light-Emitting Diodes

In this study, two blue fluorescent using phenylanthracene-substituted furan derivatives were synthesized for organic light-emitting diodes (OLEDs) and subsequently characterized. To study the electroluminescent properties of the materials, OLED devices were fabricated using these two materials as an emissive layer (EML). The device using 7,7-diphenyl-9-(10-phenylanthracen-9-yl)-7H-fluoreno[4,3-b]benzofuran in the emitting layer showed the highest external quantum efficiency (EQE) value, 3.10%. It also showed the maximum luminance efficiency of 2.41 cd/A and maximum power efficiency of 1.90 lm/W with CIE coordinates of (0.15, 0.08).

Position Effects of Metal Nanoparticles on the Performance of Perovskite Light-Emitting Diodes

Metal nanoparticles have been widely used for improving the efficiencies of many optoelectronic devices. Herein, position effects of gold nanoparticles (Au NPs) on the performance of perovskite light-emitting diodes (PeLEDs) are investigated. Amphiphilic Au NPs are synthesized so that they can be incorporated into different layers of the PeLEDs to enhance device efficiencies. The photoluminescent (PL) studies indicate apparent position effects; the strongest PL intensity occurs when the NPs are directly blended with the light-emitting perovskite layer. In contrast, the PeLEDs exhibit the highest luminance efficiency while the Au NPs are placed in the hole-transporting layer. The direct blending of the NPs in the perovskite layer might affect the electrical properties, resulting in inferior device performance. The results reported herein can help to understand the enhancing mechanism of the PeLEDs and may also lead to even better efficiencies in the near future.

Red Y2O3:Eu-Based Electroluminescent Device Prepared by Atomic Layer Deposition for Transparent Display Applications

Y2O3:Eu is a promising red-emitting phosphor owing to its high luminance efficiency, chemical stability, and non-toxicity. Although Y2O3:Eu thin films can be prepared by various deposition methods, most of them require high processing temperatures in order to obtain a crystalline structure. In this work, we report on the fabrication of red Y2O3:Eu thin film phosphors and multilayer structure Y2O3:Eu-based electroluminescent devices by atomic layer deposition at 300 °C. The structural and optical properties of the phosphor films were investigated using X-ray diffraction and photoluminescence measurements, respectively, whereas the performance of the fabricated device was evaluated using electroluminescence measurements. X-ray diffraction measurements show a polycrystalline structure of the films whereas photoluminescence shows emission above 570 nm. Red electroluminescent devices with a luminance up to 40 cd/m2 at a driving frequency of 1 kHz and an efficiency of 0.28 Lm/W were achieved.

Efficient white light-emitting polymers from dual thermally activated delayed fluorescence chromophores for non-doped solution processed white electroluminescent devices

Conjugated TADF copolymers comprised of two TADF molecules linked with carbazole exhibited stable pure white emission from non-doped OLEDs with CIE coordinates (0.32, 0.35), a maximum luminance efficiency of 9.13 cd A−1, and a maximum EQE of 4.17%.

Luminance efficiency roll-off mechanism in CsPbBr3−xClx mixed-halide perovskite quantum dot blue light-emitting diodes

Efficiency roll-off is a significant issue in blue light-emitting diodes (LEDs), but its origin still remains controversial.

High stability and luminance efficiency thieno[2,3-d]pyridazine-based iridium complexes and their applications in high-performance yellow OLEDs

An OLED based on complex 1 shows promising efficiencies of 18.2%, 58.5 cd A−1 and 45.9 lm W−1 which are 40% higher than those of PO-01.