Hua Yu-Lin

Tandem white organic light-emitting diodes adopting a C60:rubrene charge generation layer

Organic bulk heterojunction fullerence (C60) doped 5, 6, 11, 12-tetraphenylnaphthacene (rubrene) as the high quality charge generation layer (CGL) with high transparency and superior charge generating capability for tandem organic light emitting diodes (OLEDs) is developed. This CGL shows excellent optical transparency about 90%, which can reduce the optical interference effect formed in tandem OLEDs. There is a stable white light emission including 468 nm and 500 nm peaks from the blue emitting layer and 620 nm peak from the red emitting layer in tandem white OLEDs. A high efficiency of about 17.4 cd/A and CIE coordinates of (0.40, 0.35) at 100 cd/m2 and (0.36, 0.34) at 1000 cd/m2 have been demonstrated by employing the developed CGL, respectively.

Pure RGB Emissions Based on a White OLED Combined with Optical Colour Filters

We report on a white organic light emitting device (OLED) with a single light emitting layer consisting of a greenish-white emitting host bis-(2-(2-hydroxyphenyl) benzothiazole)zinc (Zn(BTZ)2) and an orange-red dopant 5,6,11,12-tetraphenylnaphthacene (rubrene). The Commission Internationale De LEclairage (CIE) coordinates, external quantum efficiency, and brightness of the white OLED are (0.341, 0.334), 0.63% and 4000xa0Cd/m2 at the bias of 20xa0V, respectively. Pure red-green-blue (RGB) emissions have been successfully achieved from the white OLED combined well with several built-in optical colour filters (CFs). The CIE coordinates of the white mixture calculated in theory are very close to the coordinates of the white mixture which recorded with spectrophotometer in practice.

Improving the Efficiency of Blue Organic Light-Emitting Diodes by Employing Cs-Derivatives as the n -Dopant

The efficiency of organic light-emitting diodes (OLEDs) was markedly improved using the novel electron transporting material 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (NBPhen) doped with Cs-derivatives including cesium carbonate (Cs2CO3) and cesium acetate (CH3COOCs) as the n-type dopant. The operating voltage of devices containing these materials as an n-type electron transporting layer (n-ETL) was significantly reduced. Optimized devices with Cs2CO3-doped or CH3COOCs- doped n-ETL (ITO/β-NPB/CBP:5%(w) N-BDAVBi/NBPhen/NBPhen:Cs2CO3 (or CH3COOCs)/Al) exhibited

Effect of TPD films as electron blocking layer on EL spectrum

In an organic thin film electroluminescence (OTFEL) device with an ITO/PPV/Alq:DCM1/A1 structure, a TPD layer was inserted between the PPV and Alq:DCM1 layers. A device without the TPD layer or with a 5-nm thick TPD layer operating at higher DC voltage (≥8 V) exhibited EL emission from both the PPV (513 nm) and Alq:DCM1 (591 nm) layers, however, a device with a 5-nm thick TPD layer operating at lower voltage (<7 V) or with a 10-nm thick TPD layer had an EL emission peak at 591 nm, implying that the TPD layer can effectively block electron transportation. Hence we can spatially control the carrier recombination zone and obtain different EL emissions by adjusting the thickness of the carrier blocking layer and the driven voltage.

Organic Light Emitting Diode Using Inorganic Material as Electron Transport Layer

In this letter we report a new kind of organic light emitting diode in which an inorganic material was used as electron transport layer. The incorporation of this inorganic material layer increased the brightness in one order.