DCM Derivatives Research Articles

Photophysical Properties of 4-Dicyanomethylene-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran Revisited: Fluorescence versus Photoisomerization.

Although 4-dicyanomethylene-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran (DCM) has been known for many decades as a bright and photostable fluorophore, used for a wide variety of applications in chemistry, biology and physics, only little attention has been paid so far to the presence of multiple isomers and conformers, namely s-trans-(E), s-cis-(E), s-trans-(Z), and s-cis-(Z). In particular, light-induced E-Z isomerization plays a great role on the overall photophysical properties of DCM. Herein, we give a full description of a photoswitchable DCM derivative by a combination of structural, theoretical and spectroscopic methods. The main s-trans-(E) isomer is responsible for most of the fluorescence features, whereas the s-cis-(E) conformer only contributes marginally. The non-emitting Z isomers are generated in large conversion yields upon illumination with visible light (e.g., 485 or 514 nm) and converted back to the E forms by UV irradiation (e.g., 365 nm). Such photoswitching is efficient and reversible, with high fatigue resistance. The E→Z and Z→E photoisomerization quantum yields were determined in different solvents and at different irradiation wavelengths. Interestingly, the fluorescence and photoisomerization properties are strongly influenced by the solvent polarity: the fluorescence is predominant at higher polarity, whereas photoisomerization becomes more efficient at lower polarity. Intermediate medium (THF) represents an optimized situation with a good balance between these two features.

Synthesis of 2-(2, 6-Bis((E)-4-(dialkylamino)styryl)-4H-pyran-4 ylidene) Malononitrile (bis-DCM) from Nucleophilic Aromatic Substitution (SNAr) Reaction

Background: Functional organic dyes with donor-π-conjugation-acceptor (D-π-A) molecular structure and electron transfer in the excited state have attracted much attention because of their potential applications in optical, electronics, magnets materials, dye sensitized solar cells (DSSCs), organic light emitting diodes (OLED), sensors, solid state lasers and photovoltaic cells and thin film transistors. Methods: An efficient and convenient method for synthesis of 2,6-bis-[2-(4-dialkylaminophenyl) vinyl]- 4H-Pyran-4-one starting from reaction of 4-fluorobenzaldehyde with 2,6-dimethyl-4H-pyran-4- one in the presence of MeONa as base was described. In continuation, secondary amines were reacted with 2,6-bis((E)-4-fluorostyryl)-4H-pyran-4-one and 2,6-bis-[2-(4-dialkylaminophenyl)vinyl]-4HPyran- 4-one was obtained as the final product. 1H and 13C NMR, FT-IR spectroscopy supported the predicted structure of the products. The UV-Vis absorption spectra of synthesis compound were measured in diluted dichloromethane solution. Results: Knoevenagel reaction of 4-fluorobenzaldehyde and 2,6-dimethyl-4H-pyran-4-one to afford 2,6-bis((E)-4-fluorostyryl)-4H-pyran-4-one was performed in room temperature.To optimize the reaction conditions, a variety of solvents (EtOH, MeOH, t-BuOH) and bases (KOH, NaOH, EtONa, Me- ONa, t-BuONa) were tested; MeOH/MeONa system was selected as the best condition for this step. The best operative system for nucleophilic aromatic substitution of secondary amines with 2,6-bis((E)- 4-fluorostyryl)-4H-pyran-4-one was obtained when DMF was used as a solvent and K2CO3 was employed as the base and HDTMAB as ligands. In addition, malononitrile was reacted with 2,6-bis((E)-4- fluorostyryl)-4H-pyran-4-one and obtained compound was employed in SNAr reaction. The UV-Vis spectroscopy studies were carried out in diluted dichloromethane solution (5×10-5 M) on the synthesized bis-condensed DCM derivatives. Conclusion: In summary, this study focused on preparation of novel compounds with bis-DCM-type skeleton for application in organic light-emitting diodes, for this purpose, 2,6-bis-[2-(4-dialkylaminophenyl) vinyl]- 4H-Pyran-4-one derivatives were prepared from reaction of 4-fluorobenzaldehyde with 2,6-dimethyl- 4H-pyran-4-one in the presence of MeONa as base. In continuation, secondary amines were reacted with 2,6-bis((E)-4-fluorostyryl)-4H-pyran-4-one and 2,6-bis-[2-(4-dialkylaminophenyl) vinyl]-4HPyran- 4-one was obtained as the final product. Additionally, reaction of malononitrile as an active methylene group with 2,6-bis((E)-4-fluorostyryl)-4H-pyran-4-one before N-arylation reaction resulted in 2-(2,6-bis(4-(dialkylamino)styryl)-4H-pyran-4ylidene)malononitrile derivatives. Keywords: Bis-DCM, malononitrile, push-pull system, SNAr, organic light-emitting diodes (OLED), Knoevenagel condensation.

Stimulated emission and optical properties of pyranyliden fragment containing compounds in PVK matrix

Organic solid state lasers are thoughtfully investigated due to their potential applications in communication, sensors, biomedicine, etc. Low amplified spontaneous emission (ASE) excitation threshold value is essential for further use of the material in devices. Intramolecular interaction limits high molecule density load in the matrix. It is the case of the well-known red light emitting laser dye - 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM). The lowest ASE threshold value of the mentioned laser dye could be obtained within the concentration range between 2 and 4wt%. At higher concentration threshold energy drastically increases. In this work optical and ASE properties of three original DCM derivatives in poly(N-vinylcarbazole) (PVK) at various concentrations will be discussed. One of the derivatives is modified DCM dye in which the methyl substituents in the electron donor part have been replaced with bulky trityloxyethyl groups (DWK-1). These sterically significant functional groups do not influence electron transitions in the dye but prevent aggregation of the molecules. The chemical structure of the second investigated compound is similar to DWK-1 where the methyl group is replaced with the tert-butyl substituent (DWK-1TB). The third derivative (DWK-2) consists of two N,N-di(trityloxyethyl)amino electron donor groups. All results were compared with DCM:PVK system. Photoluminescence quantum yield (PLQY) is up to ten times larger for DWK-1TB with respect to DCM systems. Bulky trityloxyethyl groups prevent aggregation of the molecules thus decreasing interaction between dyes and amount of non-radiative decays. The red shift of the photoluminescence and amplified spontaneous emission at higher concentrations were observed due to the solid state solvation effect. The increase of the investigated dye density in the matrix with a smaller reduction in PLQY resulted in low ASE threshold energy. The lowest threshold value was obtained around 21μJ/cm2 (2.1kW/cm2) in DWK-1TB:PVK films.

Rational design of novel near-infrared fluorescent DCM derivatives and their application in bioimaging.

The development of innovative strategies for high-performance near-infrared (NIR) fluorescent materials is in urgent demand for bioimaging. By replacing the stronger electron-withdrawing groups or extending the π-conjugated system, novel NIR fluorescent materials of DCM analogues have been developed, along with several striking characteristics: bright NIR fluorescence over 700 nm, large Stokes shift and good photo-stability. It is demonstrated that introducing a stronger electron-withdrawing unit to the acceptor moiety of DCM analogues is a favourably efficient strategy to tune and prolong the emission wavelength into the NIR region with a large Stokes shift. In comparison with the commercial NIR dye ICG, S-DCM-N and S-DCM-P display excellent photostability and low photobleaching. The large Stokes Shift and NIR fluorescence channel of S-DCM-N and S-DCM-P are very favourable for fluorescence labelling with a high signal-to-noise ratio in living species.

Solid state solvation effect and reduced amplified spontaneous emission threshold value of glass forming DCM derivative in PMMA films

Molecule crystallization is one of the limitations for obtaining high-gain organic laser systems. One of the examples is well known red laser dye 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM). The lowest threshold value of amplified spontaneous emission was achieved by doping 2wt% of DCM molecule in tris-(8-hydroxy quinoline) aluminum (Alq3) matrix. Further increase of the DCM dye concentration makes the system less efficient as its threshold value increases. It is due to large intermolecular interaction, which induces photoluminescence quenching. Compounds with reduced intermolecular interaction could be prospective in organic laser systems due to higher possible doping.In this work photoluminescence and amplified spontaneous emission properties of modified DCM molecule in poly(methyl methacrylate) (PMMA) matrix were investigated. Bulky trityloxyethyl groups were attached to the donor part of DCM. These groups increase intermolecular distance wherewith reduce photoluminescence quenching. More than one order of magnitude lower excitation threshold energy of the amplified spontaneous emission was achieved in doped polymer films with investigated compound in comparison to doped polymer with DCM. It means that the investigated compound is more perspective as a laser material compared to the previously studied. In addition, amplified spontaneous emission maximum could be tuned within 15nm by changing concentration from 0.1wt% to 10wt% DWK-1 in PMMA matrix due to solid state solvation effect.

Red fluorescent DCM derivatives with the bulky adamantyl and bicyclo[2,2,2]octyl groups for organic light emitting diodes (OLEDs)

A red fluorescent compound, 4-(dicyanomethylene)-2-(1-pentylbicyclo[2,2,2]oct-4-yl)-6-(1-adamantyl-1,7,7-trimethyljulolidyl-9-enyl)-4H-pyran containing bulky adamantyl and 1-pentylbicyclo[2,2,2]octyl groups on a DCM backbone, was synthesized and characterized. In a red device using this material as a dopant, a luminous and power efficiency of 3.21 cd/A and 1.68 lm/W was achieved, respectively, at 20 mA/cm2 with the CIE coordinates of (x = 0.60, y = 0.39) at 7.0 V.

Fluorescent dyad for cooperative recognition of copper cation and halogen anion

TMS-ethynyl triazolyl benzothiadiazole (BTD) derivatives have been successfully synthesized by mono deprotection of di-TMS-ethynyl BTD followed by click chemistry. The fluorescence intensity of TMS-ethynyl triazolyl BTD–DCM dyad 8, as well as triazolyl BTD 3, and the DCM derivative 7 could be selectively quenched by Cu2+, but almost not affected by different tested anions. Interestingly, the fluorescence emission of DCM-based fluorophores 7 and 8 was highly sensitive to a combination of Cu2+, F−, or Br− in a sequence dependent manner. With the dyad 8, the detection limit as low as 0.13ppb could be attained for F− in MeCN. The Cu2+-promoted aerobic oxidative dimerization of DCM moiety to tetrahydrofuran derivatives has also been demonstrated for the first time.

Red Fluorescent DCM Derivatives with the Bulky-substituents on Pyran and Julolidine Moieties for Organic Light-Emitting Diodes (OLEDs)

In most DCM type emitters, concentration quen-ching due to excimer and exciplex formation dramaticallyreduces EL performance. Among those, 4-(dicyanomethyl-ene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4 H-pyran (DCJTB) represents one of the most efficient fluore-scent red emitting materials for OLEDs. In DCJTB, thebulky substituents such as four methyl groups on julolidinemoiety and tert-butyl group on pyran moiety of DCM back-bone are incorporated to prevent concentration quenchingbetween the emitting materials, which lead to the improvedEL efficiencies of devices using them.

Theoretical Studies of DCM Derivatives with Dual Electron Donating Group

Novel red emitting bis-condensed DCM derivative with dual homoleptic or heteroleptic electron donating groups (EDG), bis-DCM, bis-DCMOEH and bis-DCMNOEH were designed and their photonic properties were studied theoretically in order to tune the emission wavelength of the deep red region and to enhance the luminescence efficiencies. To gain insight into the factors responsible for the emission color change and the enhanced luminescence efficiencies, we performed the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations of these bis-condensed DCM derivatives. The results showed that the bis-condensed DCM derivatives gave more red-shifted emission than the mono-substituted DCM derivatives. In addition, when the electron-donating ability of EDG is increased, the bandgap of the bis-condensed DCM derivative becomes small, resulting in more red-shifted emission. The PL emission maxima of bis-DCMNOEH at 600 nm showed that the excited energy was absorbed from both DCM and DCMOEH moieties. The energy placed in their excited state of the DCMOEH moiety was transferred to the DCM moiety and light was emitted from DCM moiety in the end.

Post-UV survival and mutagenesis in DNA repair-proficient and -deficient strains of Escherichia coli K-12 grown in 5-azacytidine to inhibit DNA cytosine methylation: evidence for mutagenic excision repair.

Inhibition of cytosine methylation by growth in 5-azacytidine (5-azaC), did not affect the sensitivities to DNA damage induced by exposure to ultraviolet light (UV) of Escherichia coli K-12 strains AB1157 dcm+, which is fully DNA repair-proficient, LR68 (a dcm derivative of AB1157), JC3890 dcm+ uvrB, deficient in error-free excision repair, TK702 dcm+ umuC, deficient in error-prone repair, or TK501 dcm+ uvrB umuC, which lacks both excision repair and error-prone repair. However, growth in 5-azaC increased the post-UV survival of strains AB2463 recA(Def), AB2470 recB and AB2494 lexA(Ind-), which are deficient in the induction or expression of recombination repair or error-prone repair of DNA. Spontaneous mutation frequencies were increased in strains LR68, AB2463, AB2470 and AB2494 by growth in 5-azaC, but remained unaltered in strains AB1157, JC3890, TK702 or TK501. Growth in 5-azaC significantly increased UV-induced mutation frequencies in strains AB2463 and AB2470, significantly reduced UV-induced mutation in strain JC3890, but had little effect on UV-induced mutation in the other strains. The results suggest that 5-azaC may induce a normally error-free DNA repair pathway to become error-prone and therefore genotoxic.

Column Chromatography: A Facile and Inexpensive Procedure to Purify the Red Dopant DCJ Applied for OLEDs

DCJ, one of the DCM derivatives, has been used as a laser dye and a red emitter or a red dopant for OLED devices in recent decade. 4-(dicyanomethylene)-2-methyl-6-(julolidyl-9-enyl)-4H-pyran (DCJ) containing julolidine group has been synthesized for use as a red fluorescent dye molecule in organic light-emitting di- odes (OLEDs). In this paper, we reported a facile, simple and inexpensive procedure of purification of DCJ without necessity of HPLC analysis. The maximum absorption, emission, quantum efficiency are increasing in DCJ with the electron-donating of julolidine group.

Synthesis and luminescence behavior of inorganic–organic hybrid materials covalently bound with pyran-containing dyes

A DCM derivative, namely 4-Dicyanomethylene-2-methyl-6-{[4′-(N-hydroxyethyl-N-methyl)amino]styryl}-4H-pyran (DCMH), has been synthesized and covalently incorporated into the inorganic silica network as pendants via a sol–gel process. Molecular structures of the resultants are confirmed by elemental analysis, 1H NMR, DSC, TGA, FTIR and UV–Vis spectroscopy. Photoluminescence (PL) spectra shows that the emission of DCMH peaked at 625 nm is almost completely quenched in DMF solution with a concentration of 1 × 10−4 mol/L, however, in hybrid films, the PL intensity enhances obviously with increasing DCMH concentration even at the high loading content of 40 mol%. All the hybrid films exhibit PL emission around 646–650 nm and the peak position reveal little dependence on the concentration of dye, suggesting they can be used as red emissive materials in light-emitting diodes. The relationship between fluorescence lifetime and dye concentration is also investigated by time-resolved PL measurements.

Theoretical study of solvent effect on one- and two-photon absorption properties of starburst DCM derivatives

The equilibrium geometries, electronic structures, one-photon absorption (OPA) and two-photon absorption (TPA) properties of starburst 4-(dicyanomethylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran (DCM) derivatives have been studied by using density functional theory (DFT) and Zerner's intermediate neglect of differential overlap (ZINDO) program. Results showed that increasing the number of branches in DCM molecules and introducing stronger electron withdrawing groups are efficient ways to enhance the TPA cross sections. For the two- and three-branched molecules of the DCM derivatives, the solvent effect on the OPA and TPA properties was also considered by adapting the self-consistent reaction field (SCRF) theory with the polarizable continuum model (PCM) to model the interaction with the solvent in ZINDO program. The calculated molecular structure, transition dipole moment and intramolecular charge transfer (ICT) in different solvents have been analyzed to approximate how the solvent affects the TPA cross section. Results indicated that the TPA cross section increases as the polarity of the solvents increases, and it reaches a maximum when the dielectric constant epsilon equals 20.7.

Organic white light-emitting diodes using a new DCM derivative as an orange-red doping molecule

A new DCM derivative containing a phenothiazine moiety, 4-(dicyanomethylene)-2- t-butyl-6 -(9-ethylphenothiazine-2-enyl) -4 H-pyran (DCPTZ), has been synthesized for use as an orange-red fluorescent dye molecule in organic light-emitting diodes (OLEDs). EL devices with the structure ITO/PEDOT-PSS/α-NPD/Alq 3:DCPTZ/Alq 3/LiF/Al were fabricated with various DCPTZ doping concentrations. The maxima in the EL spectra of the devices varied from 580 to 620 nm depending on the doping concentration of the dye molecule. An EL device with 0.5% dopant concentration was found to exhibit a maximum brightness of 81,500 cd/m 2 at 13.3 V and a power efficiency of 4.1 lm/W with CIE coordinates (0.51, 0.47) at a luminance of 100 cd/m 2. White light-emitting devices with the structure ITO/PEDOT-PSS/α-NPD/α-NPD:DCPTZ/DPVBi/Alq 3/LiF/Al were also fabricated. The thickness of the blue light-emitting 1,4-bis(2,2-diphenylvinyl)benzene (DPVBi) layer was varied to obtain white light emission. White light emission from the device was observed when the thickness of the DPVBi layer was greater than 10 nm. The maximum brightness and power efficiency of the device with a 20-nm DPVBi layer were found to be 30,300 cd/m 2 and 2.0 lm/W, respectively, with CIE coordinates (0.33, 0.36). In addition, the white EL device exhibits a relatively high color rendering index (CRI) of about 83.

Synthesis, Photophysics, and Electroluminescence of Copolyfluorenes Containing DCM Derivatives

New copolyfluorenes (PFD0.5−50) of 9,9‘-dihexylfluorene and 2-(2,6-bis(4-(2-phenyl-2-cyanovinyl)-2,5-bis(hexyloxy)styryl)-4H-pyran-4-ylidene)malononitrile (DCM) were synthesized by the Suzuki coupling reaction. They were characterized by molecular weight determination, elemental analysis, FT-IR spectroscopy, DSC, TGA, absorption and emission spectroscopy, and cyclic voltammetry (CV). The copolymer films showed absorption peaks at 383−397 and 481−496 nm, and PL peaks at 421−424 and 560−596 nm originated from fluorene and DCM segments, respectively. The longer wavelength PL peak red-shifted gradually from 560 to 596 nm with increasing DCM contents (0.83%→49.8%). The LUMO energy levels lowered as the content of DCM units increased (−2.75 eV→−3.70 eV), whereas the HOMO levels remained almost unchanged (−5.68 eV→−5.64 eV). Electroluminescent devices, ITO/PEDOT:PSS/polymer/Ca(50 nm)/Al(150 nm), were fabricated to investigate the influence of DCM contents on emission characteristics. The maximum brightness and c...

Synthesis and Luminescent Properties of Fluorene Copolymers Bearing DCM Pendants

A series of copolymers, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4-dicyanomethylene-2-methyl-6-[4-(diphenylamino)styryl]-4H-pyran-4‘,4‘ ‘-diyl)], were synthesized by polymerizing 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9,9-dioctylfluorene with mixtures of 2,7-dibromo-9,9-dioctylfluorene and 4-dicyanomethylene-2-methyl-6-[bis(4‘-bromophenyl)amino]styryl]-4H-pyran (a DCM derivative) by the palladium-catalyzed Suzuki coupling reaction. The copolymers were characterized by molecular weight determination, elemental analysis, 1H NMR, FT-IR spectroscopy, DSC, TGA, UV−vis spectroscopy, and photoluminescence (PL) and electroluminescence (EL) spectroscopy. The copolymers showed two absorption peaks at 380 and 485 nm, and the long-wavelength absorption increased with increasing the fraction of the DCM comonomer. The PL spectra of copolymers in chloroform solution displayed emission from both the main chain (420 nm) and DCM units (620 nm). In the solid state, however, PL spectra of copolymers showed only the long wavelength red emission at 620 nm with no trace of emission from the main chain, which implies a facile exciton migration or energy transfer to the lower energy sites from the fluorene part to the DCM part. This results in emission of only the red light originating from the latter segments. A study on time-resolved PL rise and decay of the polymers clearly supports the energy transfer mechanism. Light-emitting diode (LED) devices were fabricated to have the configuration of ITO (indium−tin oxide)/PEDOT/polymer/Li:Al alloy. EL spectra of the devices showed only red emissions as observed in the PL spectra of the polymers' thin films. EL efficiency decreased with increasing DCM contents. When a tris(8-hydroxyquinolinato)aluminum (Alq3) layer was inserted between the emitting polymer layer and the cathode to make the ITO/PEDOT/polymer/Alq3/Li:Al alloy configuration, the device efficiencies became much higher (∼10-2%) than those (5 × 10-5−5 × 10-3%) of single-layer devices.

Theoretical investigation of electro-luminescent properties in red emission DCM, DCJ, RED and DAD derivatives

During last decade, the DCM derivatives have been used as a laser dye and a red emitter or a red dopant for OLED devices. A series of unsymmetrical DCM, DCJ, and RED as well as symmetrical DAD derivatives of DCM have been recently synthesized and proposed for the commercial applications. It is found experimentally that the optical properties of these materials are determined by their electronic structure. However, no reliable and accurate computational method exists to predict the spectral properties currently. In this paper, we used the semiempirical AM1 and ab initio DFT methods to generate the optimized structures of DCM, DCJ, RED and DAD derivatives. Using the semiempirical ZINDO and ab intio TD-DFT methods, we generated the excitation and emission energies for these derivatives. According to the calculation results, the red shift in the excitation wavelength is in the order RED>DCJ>DCM, the maximum absorption and emission are increasingly red-shifted in DCM derivatives with the electron-donating of the different substituents in the aniline as electron-donating group or with the electron-withdrawing abilities of different substituents in the pyran as electron-withdrawing group.

Organic light-emitting diode using a new DCM derivative as an efficient orange–red doping molecule

A new DCM derivative containing the phenoxazine moiety (DCPXZ) has been synthesized for use as a red fluorescent dye molecule in organic light-emitting diodes (OLEDs). The photoluminescence and electroluminescence properties of DCPXZ were examined. The maximum photoluminescence of DCPXZ in chloroform solution (10−5 mol) was observed at 616 nm. EL devices were fabricated with the structure ITO/PEDOT-PSS/Cu-PC(15 nm)/α-NPD(45 nm)/Alq3:DCPXZ(30 nm)/Alq3(30 nm)/LiF(0.5 nm)/Al. The maximum EL emission for the 2.0% DCPXZ-doped device was at 608 nm with CIE coordinates (0.57,0.42). The EL device exhibited a maximum brightness of 15,000 cd/m2 at 19.4 V and a power efficiency of 1.04 lm/W at a luminance of 100 cd/m2.

Synthesis and Characterization of DCM Derivatives for Red Light Emitting OLEDs

A novel red light emitting material, 2,6-dimethyl-4H-pyran-4'-ylidene)malononitrile (d-DCM) was synthesized and characterized UV/visible absorption maximum is observed at 488 nm and emission maximum at 658 nm in solid film state, respectively. The organic light emitting diodes (OLEDs) with structure of indium tin oxide (ITO)/ buffer layer/ hole transporting layer/ emitting layer/ electron transporting layer/ LiF/ Al. The hole transporting layer was composed of TPD and the electron transporting layer, which consists of Alq 3 , and emitting layer was composed of d-DCM. We investigated the characteristics of electroluminescence (EL) for OLEDs with red light emitting d-DCM.

Synthesis and Characterization of DCM Derivatives for Red Light Emitting OLEDs

A novel red light emitting material, 2,6-dimethyl-4H-pyran-4'-ylidene)malononitrile (d-DCM) was synthesized and characterized. UV/visible absorption maximum is observed at 488 nm and emission maximum at 658 nm in solid film state, respectively. The organic light emitting diodes (OLEDs) with structure of indium tin oxide (ITO)/buffer layer/ hole transporting layer/ emitting layer/ electron transporting layer/ LiF/ Al. The hole transporting layer was composed of TPD and the electron transporting layer, which consists of Alq 3 , and emitting layer was composed of d-DCM. We investigated the characteristics of electroluminescence (EL) for OLEDs with red light emitting d-DCM.