Exciton scattering, κ selection rule, exciton bandwidth in pyrene microcrystallites, and lattice relaxation energy for the origin of V luminescence

Oeda, Y.; Nishi, Osamu; Matsushima, Yoshihiro; Mizuno, Ken-ichi; Matsui, Atsuo; Michinomae, Masanao; Takeshima, Masumi; Goto, T.

doi:10.1016/s0301-0104(96)00261-3

Cited by 16 publications

(10 citation statements)

References 9 publications

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“…In perylene nanocrystals with sizes of a few hundreds of nanometers, a blueshift of the excimer fluorescence peak of ≈70 meV due to lattice softening has been reported. [ 10 ] Hence, the possible reasons for the spectral blueshift with decreasing nanocrystal size are the conventional surface effects, the quantum effects involving the site shift effect [ 47,48 ] (Figure S3, Supporting Information) depending on the specific surface area (characteristic of organic nanocrystals) and the exciton confinement, lattice softening, or combined effect. The amount of blueshift due to the site shift effect is difficult to estimate accurately because of the large number of constituent molecules of BP2T nanocrystals.…”

Section: Resultsmentioning

confidence: 99%

Observation of Size‐Dependent Optical Properties Based on Surface and Quantum Effects in Nanocrystals of 5,5′‐Bis(4‐Biphenylyl)‐2,2′‐Bithiophene

Jinjyo

Mizuno

Bando

et al. 2022

Advanced Photonics Research

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Herein, 5,5′‐bis(4‐biphenylyl)‐2,2′‐bithiophene (BP2T or PPTTPP) nanocrystals are prepared via a modified miniemulsion technique. X‐ray diffraction and selected area electron diffraction analyses reveal that the BP2T molecules stand almost upright against the crystal basal plane. With decreasing nanocrystal size, the peak energies of photoluminescence (PL) spectra are blue‐shifted in the photon energy range from the bulk crystal to the monomer state. Energy‐wavevector dispersion plots reproduced using the data of size‐dependent PL spectra indicate that the size dependence of optical properties cannot be explained by the conventional quantum confinement effect used in inorganic nanocrystals. The micro‐PL and time‐resolved PL measurements of the BP2T nanocrystals reveal that the size‐dependent optical properties can be attributed to a combined effect based on the surface effects as well as lattice softening, and quantum effects involving specific surface area‐dependent site shift effect and exciton confinement. Moreover, amplified spontaneous emission is observed from the nanocrystals ≈600–1000 nm in size, which is smaller than the size previously reported for organic systems.

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Section: Resultsmentioning

confidence: 99%

Observation of Size‐Dependent Optical Properties Based on Surface and Quantum Effects in Nanocrystals of 5,5′‐Bis(4‐Biphenylyl)‐2,2′‐Bithiophene

Jinjyo

Mizuno

Bando

et al. 2022

Advanced Photonics Research

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“…A strong dichroism is observed in 4T, a,v-DH4T, and AN for light polarized along orthogonal directions (i.e., with the electric field either along the a or the b axis of the unit cell, in full agreement with all the available data reported in the literature. [14][15][16][17] The only feature attributable to the presence of crystal twinning is the weak peak at 335 nm in the a,v-DH4T spectrum (dotted line), which, on the basis of the solved structure, 6 is expected to extinguish completely as in the case of 4T. However, from the spectra the high homogeneity and quality of these samples can be assessed.…”

Section: Optical Characterisationmentioning

confidence: 99%

Growth and characterisation of centimetre-sized single crystals of molecular organic materials

et al. 2005

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“…The latter discrepancy suggests that the two spectroscopies do not probe exactly the same species. In contrast to IR vibrational transitions, electronic transitions are associated not only with isolated molecules but also with dimers, aggregates, and crystals in which intermolecular interactions take place. ,,, …”

Section: Modelization Of Film Orientationmentioning

confidence: 99%

Spectroscopic Evidence for a Substrate Dependent Orientation of Sexithiophene Thin Films Deposited onto Oriented PTFE

Lang¹,

Horowitz²,

Valat³

et al. 1997

J. Phys. Chem. B

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Sexithiophene (6T) was deposited onto PTFE layers oriented by friction. The films were studied by polarized spectroscopy: UV−visible, IR absorption, and fluorescence. The nature of the surface and the deposition rate are shown to greatly influence the orientation of the molecules and the mesoscopic organization of the film. A quantitative analysis of the orienting influence of the PTFE substrate toward the structure of the molecular film is shown.

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Exciton scattering, κ selection rule, exciton bandwidth in pyrene microcrystallites, and lattice relaxation energy for the origin of V luminescence

Cited by 16 publications

References 9 publications

Observation of Size‐Dependent Optical Properties Based on Surface and Quantum Effects in Nanocrystals of 5,5′‐Bis(4‐Biphenylyl)‐2,2′‐Bithiophene

Observation of Size‐Dependent Optical Properties Based on Surface and Quantum Effects in Nanocrystals of 5,5′‐Bis(4‐Biphenylyl)‐2,2′‐Bithiophene

Growth and characterisation of centimetre-sized single crystals of molecular organic materials

Spectroscopic Evidence for a Substrate Dependent Orientation of Sexithiophene Thin Films Deposited onto Oriented PTFE

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