The present invention provides a heterocyclic compound and an organic light-emitting device including the heterocyclic compound. The organic light-emitting devices using the heterocyclic compounds have high-efficiency, low driving voltage, high luminance and long lifespan.

Organic light-emitting device

https://www.ks.uiuc.edu/Publications/Papers/PDF/RITZ2000/RITZ2000.pdf

A Model for Photoreceptor-Based Magnetoreception in Birds

Because of its superior stretchability, graphene exhibits rich structural deformation behaviours and its strain engineering has proven useful in modifying its electronic and magnetic properties. Despite the strain-sensitivity of the Raman G and 2D modes, the optical characterization of the native strain in graphene on silica substrates has been hampered by excess charges interfering with both modes. Here we show that the effects of strain and charges can be optically separated from each other by correlation analysis of the two modes, enabling simple quantification of both. Graphene with in-plane strain randomly occurring between −0.2% and 0.4% undergoes modest compression (−0.3%) and significant hole doping on thermal treatments. This study suggests that substrate-mediated mechanical strain is a ubiquitous phenomenon in two-dimensional materials. The proposed analysis will be of great use in characterizing graphene-based materials and devices. The spectral position of Raman peaks is a useful diagnostic for determining the degree of strain and excess electronic charges present in graphene. This study demonstrates that these two contributions can be separated from each other and therefore be obtained at the same time.

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Optical separation of mechanical strain from charge doping in graphene

Excited-state intramolecular proton transfer reactions are reviewed. Special emphasis is given to the intrinsic processes and to the mechanisms of proton transfers in relation to the nature of the intramolecular hydrogen bond ring.

Excited-state proton transfer reactions II. Intramolecular reactions

In a preceding project, functional forms for “short” Helmholtz energy equations of state for typical nonpolar and weakly polar fluids and for typical polar fluids were developed using simultaneous optimization. In this work, the coefficients of these short forms for the equations of state have been fitted for the fluids acetone, carbon monoxide, carbonyl sulfide, decane, hydrogen sulfide, 2-methylbutane (isopentane), 2,2-dimethylpropane (neopentane), 2-methylpentane (isohexane), krypton, nitrous oxide, nonane, sulfur dioxide, toluene, xenon, hexafluoroethane (R-116), 1,1-dichloro-1-fluoroethane (R-141b), 1-chloro-1,1-difluoroethane (R-142b), octafluoropropane (R-218), 1,1,1,3,3-pentafluoropropane (R-245fa), and fluoromethane (R-41). The 12 coefficients of the equations of state were fitted to substance specific data sets. The results show that simultaneously optimized functional forms can be applied to other fluids out of the same class of fluids for which they were optimized without significant loss of a...

Short Fundamental Equations of State for 20 Industrial Fluids

Magnetic Field Dependence of the Geminate Recombination of Radical Ion Pairs in Polar Solvents

Delayed fluorescence (DF.) spectra of 1,2-benzanthracene, fluoranthene, pyrene, and chrysene in methylcyclohexane were measured at −80° up to the wavenumber corresponding to the energy of two triplets. With all four compounds a weak DF. Sn S0 from the highest state Sn accessible by triplet-triplet annihilation (TTA) was found. Lifetimes of Sn calculated (a) from the ratio of the DF's Sn S0 and S1 S0 and (b) from the difference in line-width of the 0,0-transitions Sn,0 S0,0 and S1,0 S0,0 agree reasonably well. This indicates that population of the highest accessible excited singlet state is the dominating primary process in the excited singlet channel of TTA. There is no evidence for excimer formation being the first step in TTA. DF. spectra extend up to the energy of two triplets. With pyrene the intensity distribution in the hot-band region of the DF. S2 S0 suggests that in TTA the same vibrational selection rules are valid as in one-photon absorption S2 S0 and that vibrational relaxation within the S2 manifold is slow compared with internal conversion S2 ↝ S1. The experimental technique is described in detail and experimental difficulties arising from impurities and photoproduct formation are discussed.

Delayed Fluorescence from Upper Excited Singlet States Sn (n > 1) of the Aromatic Hydrocarbons 1,2‐benzanthracene, fluoranthene, pyrene, and chrysene in methylcyclohexane

Dual phosphorescence from 2-(2‧-hydroxyphenyl)benzoxazole due to keto-enol tautomerism in the metastable triplet state

By the spin-allowed annihilation of two metastable triplet states (triplet-triplet annihilation - TTA) one electronic ground state (S o ) and one electronically excited singlet (S 1 ) or triplet ( T 1 ) or quintet (Q A ) state are created, provided the sum of the excitation energies of the two metastable triplet states is sufficient for the creation of the particular excited state. On the basis of semi-empirical calculations of the excitation energies of T 1 ⌟ and Q 1 of forty-six conjugated organic compounds it is shown that Q 1 of benzene and some other compounds should be accessible through annihilation of like triplets (homo-TTA), and that Q 1 of many compounds should be accessible through annihilation of unlike triplets (hetero-TTA). The population of Q 1 , competing with that of S 1 , should cause an unusual magnetic-field dependence of the delayed fluorescence S 1 → S o . In favourable cases, the population of Q 1 should lead to an inverse (positive) magnetic high-field effect on the delayed fluorescence.

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Accessibility of the lowest quintet state of organic molecules through triplet-triplet annihilation; an indo ci study

Hydrogen tunnel effects in the metastable triplet states of 2-(2’-hydroxyphenyl)benzoxazole (HBO) and 2-(2’-hydroxy4’-methylpheny1)benzoxazole (m-MeHBO) and their deuteriooxy analogues DBO and m-MeDBO have been investigated between 35 and 250 K in three alkane solvents that have drastically different viscosities at low temperatures. In the triplet states of HBO the hydrogen transfer between the enol and keto tautomers is reversible because the two triplet states are isoenergetic. In m-MeHBO the hydrogen transfer is virtually unidirectional because the initially populated keto triplet state has a higher energy than the enol triplet state. In spite of these differences the observed hydrogen-transfer rate constants of the two compounds have nearly the same values. The temperature dependence of the rate constants is insensitive to large changes in solvent viscosity, Le., hydrogen tunneling in HBO and m-MeHBO depends on solvent friction neither at intermediate nor at very low temperatures. The couples HBO, DBO and m-MeHBO, m-MeDBO are the first examples where the determination of tunneling rate constants has been extended for both isotopomers into a temperature region where the rates and the isotope effect on these rates become temperature independent.

Keto-Enol Tautomerization of 2-(2'-Hydroxyphenyl) benzoxazole and 2-(2'-Hydroxy-4'-methylphenyl) benzoxazole in the Triplet State: Hydrogen Tunneling and Isotope Effects. 2. Dual Phosphorescence Kinetics

Bernhard Nickel

Papers

Magnetic Field Dependence of the Geminate Recombination of Radical Ion Pairs in Polar Solvents

Delayed Fluorescence from Upper Excited Singlet States Sn (n > 1) of the Aromatic Hydrocarbons 1,2‐benzanthracene, fluoranthene, pyrene, and chrysene in methylcyclohexane

Dual phosphorescence from 2-(2‧-hydroxyphenyl)benzoxazole due to keto-enol tautomerism in the metastable triplet state

Accessibility of the lowest quintet state of organic molecules through triplet-triplet annihilation; an indo ci study

Keto-Enol Tautomerization of 2-(2'-Hydroxyphenyl) benzoxazole and 2-(2'-Hydroxy-4'-methylphenyl) benzoxazole in the Triplet State: Hydrogen Tunneling and Isotope Effects. 2. Dual Phosphorescence Kinetics