Current density—voltage—luminance characteristics

Before ending this section, the current density-voltage-luminance characteristics of two PLEDs using Ag/Ca (solid symbol) and Ag/Al/CsF (open symbol) as a cathode, respectively, with 40 nm of poly(3,4-ethylene dioxythiophene) (PEDOT) polystyrene sulfonate) (PSS) as a polymer anode and 100 nm of F8BTas a green-emitting layer are depicted in Fig. 5.16. The thickness of the Ca, CsF, A1 and Ag layers is 50, 5, 80 and 100 nm, respectively. The Al/CsF instead of Cs was used as the cathode since the role of A1 on CsF is known to release Cs into the polymer [80], It can be seen that the Ca device shows much larger current density than the CsF/Al device, in contrast to the common belief that the lower work function of... 

FIGURE 6.18 Current density-voltage, luminance-voltage, and luminous efficiency-voltage characteristics measured for the OLEDs made with an AZO anode and an ITO anode. 

Figure 7.6 shows typcial current density-voltage-luminance (J-V-L) and emission characteristics of an OLED device. OLEDs have a similar electrical characteristic to that of a rectifying diode. In forward bias, the device starts with a small current at low voltages. In this region, charge carriers are injected into the device but little exciton formation, hence light... 

Figure 14.21 Eleotroluminesoenoe chemistry and spectrum (top) and (bottom) current density ( ) voltage-luminance (O) characteristics for indium-tin oxide/polymer 3 (above).

FIGURE 6.12 (a) Current density-voltage and (b) luminance-current density characteristics of OLEDs with a configuration of ITO/Alq3 interlayer/NPB/Alq3/Ca/Ag. The thickness of the Alq3 interlayer was varied over a range of 0-5.0 nm. 

FIGURE 10.14. Current-voltage-luminance characteristics of an ITO/poly-TPD (60 nm)/PFO (200 nm)/Ca LED. The current density (filled diamonds) and luminance (open triangles) are plotted as a function of bias voltage on log-linear axes. The inset shows a schematic energy-level structure for the device. (From Ref. 5.)... 

Fig. 9. EL spectrum of device with dLip 5nm (left) (inset image of a large area device) Luminance-current density-voltage characteristics (right).

The IVL (current density, apvplied voltage, luminance) characteristics of OLEDs were measured using a Photo Research Inc. PR-650 spectrometer. The operational life-time characteristics were determined from a series of measurements of changes in luminance and drive voltage as fimction of time under DC driving conditions. 

Fig. 21 Top normalized electroluminescence spectra for (dotted line) 30, (dashed line) [Pt(C1 ANAN)(C CC6H4Me-4)], and (continuous line) 40 at 4% doping level and multilayer configuration of device. Bottom current density, voltage and luminance characteristics (inset luminescent efficiency vs current density) for OLED using 30 as emitter as 4% doping level (Reproduced with permission from [36a]. Copyright 2002 Royal Society of Chemistry)...

Fig. 4.13. Comparison of pLED on conventional ITO-coated glass substrate with pLED on ITO-free PET substrate, (a) Current density-voltage characteristics, (b) Luminance-voltage characteristics...

Figure 6. Luminance-voltage, current density-voltage characteristics of o-Mc PTPDMA (200A) / Alq (70GA) devices.

FIGURE 6.9 Current density vs. bias voltage (a) and luminance vs. current density (b) characteristics of identical devices made on ITO anodes treated under different oxygen plasma conditions. 

FIGURE 7.6 Typical current density (filled squaresj-voltage-luminance (open squares) (J-V-L) and emission characteristics (inset figure) of an OLED device. This J-V-L data is from the device discussed later in Figure 7.10. 

Fig. 9.13. Luminous efficiencies for the UDC The inset shows almost identical current PhOLED deposited by OVPD (circles) and VTE density-voltage characteristics of the (squares). The VTE device reaches a maximum PhOLED deposited by OVPD and VTE. efficiency of 24 cd A-1 whereas that for the (Figure courtesy of UDC.)...

Figure 19.11 shows the current density (top panel) and the luminance (bottom panel) dependence on applied bias of (a) ITO/PDPV/Ca/Al and (b) ITO/PEDOT PSS/PDPV/Ca/Al. Clearly, the incorporation of the 60 nm thick PEDOTiPSS layer has a dramatic influence on the device s characteristics. Both the current and luminance increase considerably at a fixed voltage. A substantial reduction in operating voltages (Vop) is also observed. At 0.1 cd/m (and also at 0.1 mA/cm ), Vqp decreases from over 30 V for the structure without PEDOT, to less than 20 V for the structure with PEDOT. 

---