Search

SUMMARY Organic photodetectors based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blends with indium tin oxide (ITO) modified by phosphonic acid-based self-assembled monolayer (SAM) treatment in a short time are investigated. The mixed SAMs serve to tune the surface free energy and the work function of ITO by varying the blend ratio. The phosphonic acid-based SAM treatment results not only in lowering of the injection barrier at the ITO/organic layer interface but also in the lowering of the contact resistance between ITO and the organic layer, as shown by impedance spectroscopy in P3HT hole-only device with SAMs. P3HT:PCBM device with ITO modified by short treatment time of 1H,1H,2H,2H-perfluorooctane-phosphonic acid exhibits an incident-photon-to-current conversion efficiency of above 50% at -2 V, a high on/off ratio, and improved durability. [ABSTRACT FROM AUTHOR]

This study focuses on the carrier balance factor and transient characteristics of organic light-emitting diodes (OLEDs) utilizing tris[4-(5-phenylthiophen-2-yl)phenyl] amine (TPTPA) as a blue emissive material or a host material of a red phosphorescent dye, which exhibits the highest level of hole drift mobility (µ = 1.0×10-2 cm2V-1s-1) among those reported for organic disordered systems. We investigated the doping effect of a red phos-phorescent material in the TPTPA. The peak wavelengths and the shape of the electroluminescent (EL) spectra agree with those of the photoluminescent spectra, which indicate that the EL originates from the excited state of the TPTPA and dopant. The maximum luminance of approximately 11,000 and 2,000 cd/m2 were achieved for devices without and with dopant. While TPTPA device achieved good carrier balance, the hole current was decreased by doping a red phosphorescent material. Compared with the short response times of TPTPA device, relatively long response times of doped device was observed owing to phosphorescent recombination lifetime of a dopant. The TPTPA device exhibited the relatively high light outcoupling efficiency of approximately 34% (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

We studied improvement of the electrode/organic interface in organic electroluminescent diodes which consist of 8-hydroxyquinoline aluminum (Alq3) and diamine derivative (TPD). An aluminum oxide (Al2O3) monolayer was inserted between TPD and the indium tin oxide (ITO) anode. An improvement of emission is observed in a diode with an Al2O3 layer between 0.5 and 1 nm thick inserted in the surface of the anode/organic layer. The mechanism of increase in emission efficiency is discussed. © 2000 Scripta Technica Electr Eng Jpn 132(3): 14–18, 2000 [ABSTRACT FROM AUTHOR]

Poly(methyl methacrylate) (PMMA) gate dielectric formed using fluorine‐based solvent, CF3CH2OCF2CHF2 (AGC, AE‐3000), is useful to prevent mixing of the dielectric layer with the emissive layer for top‐gated organic light‐emitting transistor (OLET) device fabrication. The device performance of OLETs based on a poly(p‐phenylene vinylene) derivative, Super Yellow, is improved because of the fabrication without intermixing. For an OLET with Pt‐tetraphenyltetrabenzoporphyrin [Pt(tpbp)] doped in poly(alkylfluorene), a near‐infrared emission from Pt(tpbp) and a relatively high external quantum efficiency of approximately 1% are achieved. This device fabrication method opens perspectives in the development of the damage‐free fabrication processes in printed top‐gated OLETs. [ABSTRACT FROM AUTHOR]