This letter introduces conducting polymer compositions which can be used for hole-injection layer in organic light-emitting diodes. The compositions are composed of poly (3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonic acid (PSS) and a perfluorinated ionomer. The films based on these compositions showed much higher workfunction (∼5.3–5.7eV) than conventional PEDOT/PSS (∼5.0–5.2eV). When we fabricated blue polymer light-emitting diodes by using these compositions as a hole-injection layer, the luminescent efficiency was improved and the device lifetime was also enhanced relative to the device using the commercially available PEDOT/PSS. These compositions including perfluorinated ionomers can be one of the promising candidates for a hole-injection layer in organic light-emitting devices.

Here we report the effects of a Cs-salt based charge injection interlayer on the characteristics of topgate/bottom-contact (TG/BC) ambipolar polymer OFETs with poly(thienylenevinylene-cophthalimide)s functionalized at the imide nitrogen with dodecyl (PTVPhI-C12). P-channel dominant PTVPhI-C12 ambipolar OFETs showed both an improved electron injection and blocked hole injection properties by insertion of a thermally deposited thin CsF interlayer between Au source/drain electrodes and the organic semiconductor. X-ray and UV photoelectron spectroscopy results exhibited that the work-function of the Au electrode progressively changed from À4.5 eV to À3.9 eV and the Fermi levels of PTVPhI-C12 concomitantly moved towards the LUMO level of the conjugated polymer with an increase of CsF thickness from 0 nm to 1.5 nm, respectively. Both the shifting of Au workfunction and the molecular doping of PTVPhI-C12 by insertion of CsF provide an order of magnitude improved n-channel properties in p-channel dominant ambipolar PTVPhI-C12 OFETs. In the end, the characteristics of the PTVPhI-C12 complementary inverter were improved (gain > 23) by a selective deposition and optimization of the CsF interlayer thickness on the n-channel region of ambipolar CMOS inverters.

The authors report the effect of thermal treatment of hole-transporting interlayers between a polymeric hole injection layer and an emitting layer (EML) on the luminous efficiency and the lifetime performance in blue polymer light-emitting diodes. As the thermal annealing temperature of the interlayer increased, the hole mobility of the interlayer tended to decrease, which results in reducing the hole current injected into the EML in the devices. Hence, the device luminous efficiency decreased due to lower electron-hole balance. Nevertheless, the device lifetime increased, which can be attributed to the formation of the thicker interlayer and the better defined interlayer/EML interface.

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Abstract— A 3.0‐in. 308‐ppi WVGA top‐emission AMOLED display with a white OLED and color filters, driven by LTPS TFTs demonstrating a color gamut of >90% and a Δ(u′,v′) of <0.02 is reported. A white‐emission source with a unique device structure was developed using all fluorescent materials and yielded efficiencies of 8.45% and 16 cd/A at 4000 nits with CIE color coordinates of (0.30, 0.32).