Browsing by Author "Wu, TJ"

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Effects of metal-doped indium-tin-oxide buffer layers in organic light-emitting devices
(2006-06-01)
Chen, TH
;
Wu, TJ
;
Chen, JY
;
Liou, Y
;
顯示科技研究所
Organic light-emitting devices were fabricated by using different metal (V, Zr, Hf)-doped indium-tin-oxide (ITO) buffer layers on an ITO anode. The metal-doped ITO buffer layers were 15 nm thick with different metal concentrations. Both resistivity and work function of the ITO buffer layer were manipulated by these metal dopants. Different effects on the devices, such as reduced turn-on voltage, improved luminance, and enhanced current efficiency, were investigated. A low turn-on voltage was observed for devices with small work function and resistivity. The lowest turn-on voltage (3 V) was found on a device with a V-doped ITO buffer layer. The devices usually have a similar current density (J)-voltage (V) characteristics, but not the luminance-J or the current efficiency-J characteristics when the ITO buffer layers have the same work function. The devices with the Hf-doped ITO buffer layers show the best luminance performance among those considered. At 100 mA/cm(2), a luminance of 15,000 cd/m(2), and a current efficiency of 15 cd/A have been achieved. The balance between the carrier concentration and the energy barrier for the hole injection is possibly responsible for such performance.
Vanadium-doped indium tin oxide as hole-injection layer in organic light-emitting devices
(2005-12-12)
Chen, TH
;
Liou, Y
;
Wu, TJ
;
Chen, JY
;
顯示科技研究所
Organic light-emitting devices were fabricated by using vanadium-doped indium tin oxide (ITO) as the hole-injection layers between the hole transport layer, N,N-'-dia(1-napthl)-N,N-'-diphenyl benzidine and the ITO anode. The vanadium-doped ITO layer was 15-nm thick with three different vanadium concentrations (6, 10.5, and 12.5 mol %). Three different resistivities (10, 500, and 10 000 Omega cm) and work functions (5, 5.2, and 5.4 eV) were obtained. The device with 6 mol % V-doped ITO layer possessing the least resistivity (10 Omega cm) and work function (5 eV) has the lowest turn-on voltage (below 3 V), the lowest operating voltage (below 7 V), the highest luminance (1000 cd/m(2) below 7 V), and the highest power efficiency (>5 1m/W at 10 mA/cm(2)) among all. Such performance was attributed to the balance between the carrier concentration and the energy barrier for the hole injection.