Photoluminescence Processes in the Triplet State of Phosphorescent Organic Materials: Ir(ppy)3 Doped in TPD

Photoluminescence (PL) measurements have been made for a spin-coated thin film of phosphorescent tris(2-phenylpyridine) iridium [Ir(ppy)3] doped in N,N’-bis (3-methylphenyl)-N, N’-bis(phenyl)-benzidine (TPD) host material in the temperature range from 10 K to room temperature. When temperature is increased from 10 K to 300 K, the PL intensity of Ir(ppy)3 increases from 10 K and decreases above about 200 K. Theoretical calculations are undertaken for the temperature dependence using (1) a three-level model where three zero-field splitting substates are generated in the triplet state of Ir(ppy)3 and (2) endothermic energy transfer from the TPD host to the Ir(ppy)3 guest, and (3) energy diffusion from the excited TPD to the neighboring unexcited TPD. A good agreement was obtained between the measured and calculated temperature dependences of the PL intensity.

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Size Effects in Bi-Sb Solid Solutions Thin Films

MRS Proceedings ◽

10.1557/opl.2011.516 ◽

2011 ◽

Vol 1314 ◽

Cited By ~ 5

Author(s):

Elena I. Rogacheva ◽

Dar’ya S. Orlova ◽

Mildred S. Dresselhaus ◽

Shuang Tang

Keyword(s):

Thin Films ◽

Solid Solutions ◽

Room Temperature ◽

Thermal Evaporation ◽

Theoretical Calculations ◽

Thermoelectric Power Factor ◽

Quantum Oscillations ◽

Kinetic Coefficients ◽

Temperature Dependences ◽

Good Agreement

ABSTRACTThe room-temperature dependences of the electrical conductivity σ, Seebeck coefficient S, Hall coefficient RH, and the thermoelectric power factor P on the thickness (d=10–300 nm) of the thin films grown on mica substrates by thermal evaporation in vacuum of Bi-Sb solid solutions crystals with 4.5 at.% Sb were obtained. It was established that an increase in d up to ~ 200 nm leads to a change in kinetic coefficients and that in the thickness dependences of the thermoelectric properties, quantum oscillations were observed. It was shown that the monotonic component of the σ(T) dependence can be satisfactorily approximated by theoretical calculations based on the classical Fuchs - Sondheimer theory. The theoretically estimated period of oscillations is in a good agreement with the experimentally observed period.

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The EPR Zero-Field Splitting D and its Pressure and Temperature Dependence for Trigonal Mn2+ Centers in [Zn(H2O)6](BF4)2:Mn2+ Crystal

Zeitschrift für Naturforschung A ◽

10.1515/zna-2006-5-613 ◽

2006 ◽

Vol 61 (5-6) ◽

pp. 289-292 ◽

Cited By ~ 1

Author(s):

Hong-Gang Liu ◽

Xiao-Xuan Wu ◽

Wen-Chen Zheng ◽

Lv He

Keyword(s):

Temperature Dependence ◽

Room Temperature ◽

Coupling Mechanism ◽

Zero Field ◽

Spin Orbit Coupling ◽

Zero Field Splitting ◽

Field Splitting ◽

Thermal Expansion Coefficients ◽

Perturbation Formula ◽

Expansion Coefficients

The EPR zero-field splitting D (= b02 ) and its pressure and temperature dependence for trigonal Mn2+ centers in low and room temperature phases in [Zn(H2O)6](BF4)2 :Mn2+ crystal are studied by a high-order perturbation formula based on the dominant spin-orbit coupling mechanism. From the studies, the local trigonal distortion angles, the local angular compressibilities and the local angular thermal expansion coefficients for Mn2+ centers in both phases of the [Zn(H2O)6](BF4)2 crystal are estimated. The results are discussed

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ESR Triplet Exciton Spectrum of Acridine Orange

Zeitschrift für Naturforschung A ◽

10.1515/zna-1971-0422 ◽

1971 ◽

Vol 26 (4) ◽

pp. 763-768 ◽

Cited By ~ 2

Author(s):

Hartmut Schmidt

Keyword(s):

Triplet State ◽

Acridine Orange ◽

Exciton State ◽

Triplet Exciton ◽

Zero Field ◽

Strong Temperature Dependence ◽

Zero Field Splitting ◽

Temperature Spectrum ◽

Water Matrix ◽

Exciton Spectrum

Abstract The triplet state of acridine orange dissolved in methanol/water matrix was investigated by ESR. In absence of oxygen a strong temperature dependence of the spectra was observed. At low temperature (100 °K) the zero-field splitting parameters calculated from the triplet spectrum are: X/hc = 0.0050 cm-1, Y/hc= 0.0342 cm-1, Z/hc=0.0387 cm-1 , at higher temperature (140 °K) : X*(hc=0.0056 cm-1, Y*/hc=0.0206 cm-1, Z*/hc = 0.0262 cm-1 . It was assumed that the low temperature spectrum is caused by isolated molecules in the triplet state while the high temperature spectrum must be attributed to the triplet exciton state of the acridine orange dimer. From the theory of the ESR triplet exciton spectra it can be shown that in the dimer state of acridine orange the molecular planes form an angle of 50° or 130°. However, it cannot be excluded that the dimer configuration differs in the ground or excited singlet state from the triplet state.

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Triplet‐State Zero‐Field‐Splitting Correlations in Substituted Molecules

The Journal of Chemical Physics ◽

10.1063/1.1840473 ◽

1967 ◽

Vol 46 (10) ◽

pp. 3976-3983 ◽

Cited By ~ 24

Author(s):

B. Smaller ◽

E. C. Avery ◽

J. R. Remko

Keyword(s):

Triplet State ◽

Zero Field ◽

Zero Field Splitting ◽

Field Splitting

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Spectroscopic Investigation of V3+:YAG Crystal

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.774-776.811 ◽

2013 ◽

Vol 774-776 ◽

pp. 811-815 ◽

Cited By ~ 1

Author(s):

Jian Ma

Keyword(s):

Room Temperature ◽

Factor Model ◽

Theoretical Calculations ◽

Czochralski Method ◽

Experiment Data ◽

Crystal Field Theory ◽

Calculation Results ◽

First Time ◽

Pure Argon Atmosphere ◽

Good Agreement

V3+ions doped YAG crystals were grown using the Czochralski method in a highly pure argon atmosphere. The transmission spectrum of trivalent vanadium in YAG crystal has been measured at room temperature. Eight bands were observed in which two bands centered at 690nm (14493cm-1) and 1490nm (6711cm-1) are reported for the first time. By using the crystal-field theory and introducing the average covalent factor model, we also presented the theoretical calculations of the energy level splitting of tetrahedrally coordinated V3+impurity systems in YAG crystal. These calculation results are in good agreement with the optical experiment data.

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Hydrogen Isotope Fractionation between HCl2- Ion and HCl

Zeitschrift für Naturforschung A ◽

10.1515/zna-1975-0107 ◽

1975 ◽

Vol 30 (1) ◽

pp. 38-43

Author(s):

J. Szydłowski

Keyword(s):

Hydrogen Isotope ◽

Isotope Fractionation ◽

Theoretical Calculations ◽

Harmonic Approximation ◽

Statistical Thermodynamic ◽

Large Temperature ◽

Deuterium Isotope Effect ◽

Fractionation Factor ◽

Temperature Dependences ◽

Good Agreement

Abstract Hydrogen isotope fractionation between hydrogen dichloride ion in the condensed phase and gaseous hydrogen chloride has been studied both theoretically and experimentally. Quite good agreement between the experimental tritium fractionation factor and that theoretically calculated for two sets of vibrational data was found. Theoretical calculations of the fractionation factors of both deuterium and tritium over the large temperature range of 100-2000 K revealed some anomalies (minima and crossover points) in their temperature dependences. The relative tritium-deuterium isotope effect has also been discussed within the framework of the presently accepted statistical-thermodynamic theory in the harmonic approximation and recent works by Stern et al.

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Zero‐Field Splitting of the Ground Triplet State of Trimethylenemethane

The Journal of Chemical Physics ◽

10.1063/1.1671602 ◽

1969 ◽

Vol 50 (8) ◽

pp. 3638-3639 ◽

Cited By ~ 6

Author(s):

Yasuhiko Gondo ◽

August H. Maki

Keyword(s):

Triplet State ◽

Zero Field ◽

Zero Field Splitting ◽

Field Splitting

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Zero-field splitting in NiSiF6−6H2O and its pressure, stress and temperature dependences: A supplementary study

Applied Magnetic Resonance ◽

10.1007/bf03166929 ◽

2003 ◽

Vol 24 (3-4) ◽

pp. 277-284

Author(s):

M. Krupski ◽

A. Krupska

Keyword(s):

Zero Field ◽

Zero Field Splitting ◽

Field Splitting ◽

Temperature Dependences ◽

Pressure Stress

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Pentacene in 1,3,5-Tri(1-naphtyl)benzene: A Novel Standard for Transient EPR Spectroscopy at Room Temperature

Applied Magnetic Resonance ◽

10.1007/s00723-021-01420-4 ◽

2021 ◽

Author(s):

Mirjam Schröder ◽

Daniel Rauber ◽

Clemens Matt ◽

Christopher W. M. Kay

Keyword(s):

Epr Spectroscopy ◽

Room Temperature ◽

Glass Transition Point ◽

Zero Field ◽

Microwave Resonator ◽

Spectral Simulation ◽

Zero Field Splitting ◽

Standard Samples ◽

Epr Spectrum ◽

Data Set

AbstractTesting and calibrating an experimental setup with standard samples is an essential aspect of scientific research. Single crystals of pentacene in p-terphenyl are widely used for this purpose in transient electron paramagnetic resonance (EPR) spectroscopy. However, this sample is not without downsides: the crystals need to be grown and the EPR transitions only appear at particular orientations of the crystal with respect to the external magnetic field. An alternative host for pentacene is the glass-forming 1,3,5-tri(1-naphtyl)benzene (TNB). Due to the high glass transition point of TNB, an amorphous glass containing randomly oriented pentacene molecules is obtained at room temperature. Here we demonstrate that pentacene dissolved in TNB gives a typical “powder-like” transient EPR spectrum of the triplet state following pulsed laser excitation. From the two-dimensional data set, it is straightforward to obtain the zero-field splitting parameters and relative populations by spectral simulation as well as the $$B_{1}$$ B 1 field in the microwave resonator. Due to the simplicity of preparation, handling and stability, this system is ideal for adjusting the laser beam with respect to the microwave resonator and for introducing students to transient EPR spectroscopy.

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