Reverse Intersystem Crossing Managing Assistant Dopant for High External Quantum Efficiency Red Organic Light-Emitting Diode

Thermally activated delayed fluorescence (TADF) materials working as an assistant dopant with reduced Dexter energy transfer rate was designed by replacing the donor moiety of 2,3,5,6-tetra(9H-carbazol-9-yl) terephthalonitrile (4CzTPN) with 5H-benzo[4,5]thieno[3,2-c]carbazole...

Preparation of Double-Layer Crossed Silver Nanowire Film and Its Application to OLED

Ordered silver nanowire (AgNW) film can effectively reduce the density of nodes, reduce the roughness of the film, and increase its conductivity and transmittance. In this paper, a double-layer crossed AgNW grid film was prepared by the auxiliary stirring method. The average transmittance of the double-layer crossed AgNW grid film was found to be 80% in the 400–1000 nm band, with a square resistance of 35 Ω/sq. As a transparent conductive anode material, the ordered AgNW film was applied to fabricate a flexible green organic light-emitting diode (OLED). The experimental results showed that the threshold voltage of the OLED was only 5 V and the maximum luminance was 1500 cd/m2.

Blue Light Intensity in Organic Light-Emitting Diode and Liquid-Crystal Display Televisions

Exposure to artificial blue light from screens, especially at evening or nighttime hours, can suppress melatonin production, throw the circadian rhythm off balance, and lead to general difficulty falling asleep. This study sought to investigate the difference in blue light intensity in organic light-emitting diode (OLED) and liquid-crystal display (LCD) screens, specifically in the form of televisions. An observational and quasi-experimental method was used, using a photometer to measure light intensity and a longpass optical filter to block out light ranging from 415 to 515 nanometers, serving as the wavelength of blue light for this study. Two televisions—one OLED and one LCD—were used, with five colors being displayed on each one, one at a time. The LCD television contained more relative blue light than the OLED television for four out of the five colors displayed. On average for all colors, the LCD television emitted 24.92% more blue light than the OLED television, relative to their overall brightnesses. Limitations in scope and the potential of confounding variables interfering with data prevent any definitive conclusions from being drawn, however this study still contributes to the current body of knowledge with evidence towards a trend of lessened blue light intensity in OLED screens compared to LCD screens, which correlates with speculation by other researchers. This study sets the ground for future research investigating the potential of OLED technology in lowering exposure to blue light, thus lessening the negative impacts it can have on individuals.

Hermetic Seal of Organic Light Emitting Diode with Glass Frit

The components of OLED encapsulation with hermetic sealing and a 1026-day lifetime were measured by PXI-1033. The optimal characteristics were obtained when the thickness of the TPBi layer was 20 nm. This OLED obtained a maximum luminance (Lmax) of 25,849 cd/m2 at a current density of 1242 mA/cm2, an external quantum efficiency (EQE) of 2.28%, a current efficiency (CE) of 7.20 cd/A, and a power efficiency (PE) of 5.28 lm/W. The efficiency was enhanced by Lmax 17.2%/EQE 0.89%/CE 42.1%/PE 41.9%. The CIE coordinates of 0.32, 0.54 were all green OLED elements with wavelengths of 532 nm. The shear strain and leakage test gave results of 16 kgf and 8.92 × 10−9 mbar/s, respectively. The reliability test showed that the standard of MIL-STD-883 was obtained.

Virtual Screening of TADF Emitters for Single-Layer OLEDs

Thermally-activated delayed fluorescence (TADF) is a concept which helps to harvest triplet excitations, boosting the efficiency of an organic light-emitting diode. TADF can be observed in molecules with spatially separated donor and acceptor groups with a reduced triplet-singlet energy level splitting. TADF materials with balanced electron and hole transport are attractive for realizing efficient single-layer organic light emitting diodes, greatly simplifying their manufacturing and improving their stability. Our goal here is to computationally screen such materials and provide a comprehensive database of compounds with a range of emission wavelengths, ionization energies, and electron affinities.

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

In this work we showcase the emitter DICzTRZ in which we employed a twin-emitter design of our previously reported material, ICzTRZ. This new system presented a red-shifted emission at 488 nm compared to that of ICzTRZ at 475 nm and showed a comparable photoluminescence quantum yield of 57.1% in a 20 wt % CzSi film versus 63.3% for ICzTRZ. The emitter was then incorporated within a solution-processed organic light-emitting diode that showed a maximum external quantum efficiency of 8.4%, with Commission Internationale de l’Éclairage coordinate of (0.22, 0.47), at 1 mA cm−2.

New Low-Frame-Rate Compensating Pixel Circuit Based on Low-Temperature Poly-Si and Oxide TFTs for High-Pixel-Density Portable AMOLED Displays

A new low-frame-rate active-matrix organic light-emitting diode (AMOLED) pixel circuit with low-temperature poly-Si and oxide (LTPO) thin-film transistors (TFTs) for portable displays with high pixel density is reported. The proposed pixel circuit has the excellent ability to compensate for the threshold voltage variation of the driving TFT (ΔVTH_DTFT). By the results of simulation based on a fabricated LTPS TFT and a-IZTO TFT, we found that the error rates of the OLED current were all lower than 2.71% over the range of input data voltages when ΔVTH_DTFT = ±0.33 V, and a low frame rate of 1 Hz could be achieved with no flicker phenomenon. Moreover, with only one capacitor and two signal lines in the pixel circuit, a high pixel density and narrow bezel are expected to be realized. We revealed that the proposed 7T1C pixel circuit with low driving voltage and low frame rate is suitable for portable displays.