Papers by Keyword: Organic Light-Emitting Device

Abstract: Microlens arrays have been fabricated by 3D diffuser lithography in this study. The method mainly adopts two kinds of diffuser films with different transmittances and hazes, integrated by photolithography, polydimethylsiloxane (PDMS) molding and UV forming techniques, to get microlens arrays with different parameters and geometries. The features, such as height, geometry and fill factor of microlens arrays, are controlled by photolithography, using a photomask with circular holes and different exposure doses. The microlens arrays can also be duplicated and transferred to the surface of flexible polyethylene terephthalate (PET) substrate through PDMS molding and UV forming processes. Finally, the outcoupling efficiency of microlens arrays attached to organic light-emitting devices (OLEDs) can be measured and analyzed. More than 60% enhancement of luminous current efficiency can be obtained in experimental results.

Abstract: A orange organic light-emitting device has been fabricated with a structure of ITO/m-MTDATA (45 nm)/NPB (8 nm)/ DPVBi:DCJTB 0.5 % (15 nm)/TPBi (x nm)/Alq₃ [(60-x) n /LiF (1 nm)/Al£¬where x=0, 4, 7 and 10, respectively. N-arylbenzinmidzoles (TPBi) was used as the excton-blocking layer resulting mixture of lights from DPVBi molecules (blue-light) and DCJTB (yellow-light) molecules, thereby producing orange light emission. The performance of device can be readily adjusted by only varying the thickness of the TPBi layer. The Commission Internationale de 1'Eclairage (CIE) coordinates of the device are largely insensitive to diffrent of the driving voltages. When the thickness of TPBi is 7 nm, the device exhibits peak efficiency of 6.16 cd/A at the applied voltage of 8 V, and the maximum brightness is 43310 cd/m² at 15 V, respectively.

Abstract: Novel hole-transporting materials (M1, M2) containing triphenylamine and dipyridine units have been synthesized and characterized. Two compounds have excellent solubility in common solvents. The optical, electrochemical and thermal properties of the materials were studied in detail. The results show that two compounds have green emission in dichloromethane, high thermal stability and proper HOMO levels. The properties of compounds M1 and M2 indicate that two compounds are candidates for the application in Organic light-emitting devices as hole-transporting materials.

Abstract: Based on two novel organic materials coded as EB515 and EB 47 for fabricating a flexible OLED device, we, herewith, propose a noval testing experiment to demonstrate the electrical, optical, and lifespan performances of a flexible OLED by continuously bending it mechanically. The testing model is designed as the following: continuously cyclic bending 5000 times on a flexible OLED. After foregoing test, the findings show that the leakage current increased in the beginning of bending, then decreased; also the luminance of OLED reduced first, then recoverd. We, therefore, conclude that the reduction of leakage current and luminance may stem from the OLED surface microcracks in the process of bending. Also, after further examination to the surface of substrate by lift-offing the organic layer, we found the organic layer has been impaired and damaged, but the ITO layer remained in good condition.

Abstract: Simple method of determining emission light color in organic light-emitting diodes (OLEDs) with two emissive materials from their electroluminescent (EL) spectra has been presented. The Commission Internationale de l'Eclairage (CIE) coordinates and two EL intensity rates of OLEDs can be simulated with this method. White light OLEDs were fabricated with a blue light emission from 4,4'-bis[N-1-napthyl-N-phenyl-amino]biphenyl (NPB) and a yellow light emission from bis[2-(4-tert-butylphenyl)benzothiazolato-N,C2’]iridium (acetylacetonate) [(t-bt)2Ir(acac)], and the device shows the CIE coordinates of (0.34, 0.32) at 10 V bias, which located in white light region.