White color emitting organic electroluminescence (EL) device is a convenient means to realize full-color display because the three necessary primary colors could be obtained by color filters from white back light. In ...White color emitting organic electroluminescence (EL) device is a convenient means to realize full-color display because the three necessary primary colors could be obtained by color filters from white back light. In this paper a new three-layer device is presented. We used N, N′-bis-(lnaphhyl)-N , N′-diphenyl-1, 1′-biphenyl-4, 4′-diamine (NPB) as the hole transport layer, Alq as the electron transport layer, CuPc as the buffer layer, and TPBi as the blocking layer inserted between NPB and Alq.The 5,6,11,12-tetraphenyltetracene (Rubrene) as dopant was doped into the blocking layer.\;It was thought initially that if energy transfer existed between the host and dopant in photoluminescence (PL) of NPB doped with Rubrene, white emission might be obtained in a device such as ITO/CuPc/NPB:Rubrene/TPBi/Alq/Mg:Ag. Thus the PL of NPB:Rubrene system excited by NPB absorption band with different dopant concentrations were investigated in advance. There are two bands in the PL spectra, the blue one is emitted by NPB and the yellow one is by Rubrene. The ratio of these two bands can be adjusted by changing the Rubrene concentration. This shows that energy transfer does occur from NPB to Rubrene. Time-resolved spectra of this system, which will be given in another paper, confirm further that the energy transfer exists and is quite effective. White emission can be produced by adjusting the concentration of Rubrene in PL. However, devices of structure ITO/CuPc/NPB:Rubrene/TPBi/Alq/Mg:Ag were made according to these results with TPBi as the blocking layer, white emission can not be obtained by changing the Rubrene concentration.\;For another device of structure ITO/CuPc/NPB/TPBi:Rubrene/Alq/Mg : Ag, with a blocking layer TPBi doped by Rubrene concentration 1.5% inserted between NPB and Alq, white emission can be obtained. The highest luminance and maximum efficiency are 8635cd/m 2 and 1.39lm/W respectively , CIE coordinate x =0.31, y =0.32. The color of the emitted light can still be optimized by adjusting the relative thickness of the relevant layers and dopant concentration.\;The electroluminescence mechanism of two kinds of cells was discussed.展开更多
A mono color organic light emitting diode matrix display was reported,which has been developed based on a long life green OLED cell with 96×60 pixels,an equivalent pixel size of 0 4×0 4mm 2 and a designed dr...A mono color organic light emitting diode matrix display was reported,which has been developed based on a long life green OLED cell with 96×60 pixels,an equivalent pixel size of 0 4×0 4mm 2 and a designed driving circuit.A good green color image could be obtained,neither non uniformity caused by the parasitic capacitance nor cross talk between pixels occurred.The peak luminance at the duty cycle 1/64 was 100cd/m 2,and power consumption was 0 6W. The display panel consists of a glass substrate on which ITO anodes are formed in vertical stripes with a width of 0 4mm and a gap of 0 1mm by photolithography,then the buffer layer,hole transporting layer,electron transporting layers were successively deposited,Mg∶Ag as a cathode was evaporated and formed in horizontal stripes with a width of 0 4mm and a gap of 0 1mm by a shadow mask.Then the panel was encapsulated and the electrodes of the display were connected with the driving circuit. For the driving circuit,a line successive scanning and a constant current driving were adopted.It was designed to eliminate the cross talk between the pixels,a good green color image was realized.展开更多
文摘White color emitting organic electroluminescence (EL) device is a convenient means to realize full-color display because the three necessary primary colors could be obtained by color filters from white back light. In this paper a new three-layer device is presented. We used N, N′-bis-(lnaphhyl)-N , N′-diphenyl-1, 1′-biphenyl-4, 4′-diamine (NPB) as the hole transport layer, Alq as the electron transport layer, CuPc as the buffer layer, and TPBi as the blocking layer inserted between NPB and Alq.The 5,6,11,12-tetraphenyltetracene (Rubrene) as dopant was doped into the blocking layer.\;It was thought initially that if energy transfer existed between the host and dopant in photoluminescence (PL) of NPB doped with Rubrene, white emission might be obtained in a device such as ITO/CuPc/NPB:Rubrene/TPBi/Alq/Mg:Ag. Thus the PL of NPB:Rubrene system excited by NPB absorption band with different dopant concentrations were investigated in advance. There are two bands in the PL spectra, the blue one is emitted by NPB and the yellow one is by Rubrene. The ratio of these two bands can be adjusted by changing the Rubrene concentration. This shows that energy transfer does occur from NPB to Rubrene. Time-resolved spectra of this system, which will be given in another paper, confirm further that the energy transfer exists and is quite effective. White emission can be produced by adjusting the concentration of Rubrene in PL. However, devices of structure ITO/CuPc/NPB:Rubrene/TPBi/Alq/Mg:Ag were made according to these results with TPBi as the blocking layer, white emission can not be obtained by changing the Rubrene concentration.\;For another device of structure ITO/CuPc/NPB/TPBi:Rubrene/Alq/Mg : Ag, with a blocking layer TPBi doped by Rubrene concentration 1.5% inserted between NPB and Alq, white emission can be obtained. The highest luminance and maximum efficiency are 8635cd/m 2 and 1.39lm/W respectively , CIE coordinate x =0.31, y =0.32. The color of the emitted light can still be optimized by adjusting the relative thickness of the relevant layers and dopant concentration.\;The electroluminescence mechanism of two kinds of cells was discussed.
文摘A mono color organic light emitting diode matrix display was reported,which has been developed based on a long life green OLED cell with 96×60 pixels,an equivalent pixel size of 0 4×0 4mm 2 and a designed driving circuit.A good green color image could be obtained,neither non uniformity caused by the parasitic capacitance nor cross talk between pixels occurred.The peak luminance at the duty cycle 1/64 was 100cd/m 2,and power consumption was 0 6W. The display panel consists of a glass substrate on which ITO anodes are formed in vertical stripes with a width of 0 4mm and a gap of 0 1mm by photolithography,then the buffer layer,hole transporting layer,electron transporting layers were successively deposited,Mg∶Ag as a cathode was evaporated and formed in horizontal stripes with a width of 0 4mm and a gap of 0 1mm by a shadow mask.Then the panel was encapsulated and the electrodes of the display were connected with the driving circuit. For the driving circuit,a line successive scanning and a constant current driving were adopted.It was designed to eliminate the cross talk between the pixels,a good green color image was realized.
