Red organic light-emitting diodes using an emitting assist dopant

Abstract

We propose an emitting assist (EA) dopant system for obtaining organic light-emitting diodes (OLEDs) with pure red emission. The EA dopant (rubrene) did not itself emit but assisted the energy transfer from the host (Alq3) to the red emitting dopant (DCM2). The cell structure used was {indium tin oxide/hole injection layer [(20 nm), CuPc/hole transport layer (50 nm), NPB/emitting layer (40 nm), Alq3+DCM2 (2%)+rubrene (5 wt %)]/MgIn}. (CuPc: Copper (II) phthalocyanine, NPB: N, N′-Di(naphthalen-1-yl)-N, N′-diphenyl-benzidine, DCM2: 4-Dicyanomethylene- 2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-8-yl)vinyl]-4H-pyran). A stable red emission (chromaticity coordinates: x=0.64, y=0.36) was obtained in this cell within the luminance range of 100–4000 cd/m2. When the cell was not doped with rubrene, the emission color changed from red to orange as the luminance increased. The EA dopant system is a promising method for obtaining red OLEDs.

Communication: Influence of graphene interlayers on the interaction between cobalt phthalocyanine and Ni(111)

“…Even a graphene buffer layer cannot prevent the charge transfer at the interface to Ni(111); however, the detailed electronic situation is different. A main reason for the growing interest in transition metal phthalocyanines (TMPc) is their possible application in optoelectronic devices such as organic field effect transistors (OFETs), [1][2][3] organic light emitting devices (OLEDs), [4][5][6] organic photovoltaics (OPV), 4,7 and spintronic devices. [8][9][10] Increasing experimental and theoretical research efforts are devoted to the understanding of the electronic structure of this class of materials and in particular to related interfaces.…”

Enhanced external quantum efficiency in an organic photovoltaic cell via singlet fission exciton sensitizer

“…In this work, TPTPA and rubrene both have HOMO levels of approximately 5.4 eV. 7,8 Before OPV device fabrication, photoluminescence (PL) of a co-deposited film on glass of TPTPA(30%):rubrene(70%), by volume, was measured to characterize energy transfer from TPTPA to rubrene. The absorption coefficients and PL of TPTPA and rubrene are shown in Fig.…”

“…3(a). 7,8,[12][13][14] Control devices without the singlet fission sensitizer interlayer were also grown for comparison.…”

Donor-Acceptor-Donor Type Red Fluorescent Emitters Containing Adamandane-substituted Julolidines for OLEDs

“…[13][14][15][16] In this study, rubrene is employed as an assistant host in order to enhance energy transfer from host to dopants and thus improve the EL efficiencies.…”