On the origin of fluorescence emission in optically non-linear DCNP crystals

Morawski, Olaf; Sobolewski, Andrzej L.; Kozankiewicz, Β.; Sznitko, Lech; Miniewicz, Andrzej

doi:10.1039/c4cp03634d

Cited by 10 publications

(24 citation statements)

References 18 publications

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“…DCNP embeds well into the n ‐nonane matrix cavities, showing sharp fluorescence and fluorescence excitation lines at 5 K, which allows the isolation of two sites of the solute in the host matrix . With increasing temperature, the lines of the fluorescence spectrum broaden due to interactions with phonons, and above 80 K, only a broad vibrational envelope is observed (Figure ).…”

Section: Resultsmentioning

confidence: 99%

“…DCNP was synthesized and purified by the procedures described in ref. [14] and single crystals of DCNP were grown in the darkness from a toluene solution . The obtained crystals were crushed into powder prior to being dissolved in the investigated solvents.…”

Section: Methodsmentioning

confidence: 99%

“…DCNP embeds well into the n-nonanem atrix cavities, showing sharp fluorescencea nd fluorescencee xcitation lines at 5K, which allows the isolation of two sites of the solute in the host matrix. [19] With increasing temperature, the lines of the fluorescence spectrum broaden due to interactions with phonons, and above 80 K, only ab road vibrational envelope is observed (Figure 7). The fluorescence decays at all temperatures are exponential ( Figure S3), being independento ft he wavelength of observation, and can be well fitted to single-exponential profiles ( Figure S4).…”

Section: Spectroscopic Properties Of Dcnp Molecules In Fluid Solventsmentioning

confidence: 99%

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Environment‐Sensitive Behavior of DCNP in Solvents with Different Viscosity, Polarity and Proticity

et al. 2015

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A pyrazoline derivative, 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP), is studied by using optical spectroscopy methods in several solvents at room and at low temperatures. The DCNP molecule reveals a complex photophysics behavior, which is sensitive to solvent polarity, proticity, temperature and viscosity and arises from the presence of two rotational degrees of freedom of the dicyanovinyl group--the torsion around the double C=C bond and the s-trans-s-cis isomerization around the single C-C bond--that differently behave in various environmental conditions. The fluorescence yield of a few percent and sub-nanosecond decay times observed at room temperature make the compound useful for optical studies of liquid environments. The proticity of polar solvents can be detected with two-exponential fluorescence decays. At low temperatures, DCNP can be used as solvent viscosity or temperature fluorescent sensor.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Spectroscopic Properties Of Dcnp Molecules In Fluid Solventsmentioning

confidence: 99%

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Environment‐Sensitive Behavior of DCNP in Solvents with Different Viscosity, Polarity and Proticity

et al. 2015

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“…The frequencies of Raman shifts calculated for isolated (in vacuum) DCNP molecule in its electronic ground state were compared to the experimentally measured Raman spectrum obtained for single crystal of DCNP at 295 K. The parameters of the performed experiment are characterised in work of Morawski et al 39 Comparing data collected in Table 3 transfer appearing between the DCNP molecules plays the crucial role when the electronic properties of molecular crystal are investigated.…”

Section: Ir and Raman Spectramentioning

confidence: 99%

First Principle Calculations of the Electronic and Vibrational Properties of the 3-(1,1-Dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole Molecule

et al. 2015

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Results of first principle quantum chemical calculations of electronic and vibrational properties of the push-pull 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP) molecule are reported and discussed. The structure of DCNP was optimized with HF/6-311G methodology and found to be planar. On the basis of obtained geometry, infrared absorption and Raman spectra were computed within the HF/6-311++G** formalism. They allow to conclude that the changes of molecule dipole moment and variation of its polarizability appear at the same vibrational mode and affect the optical properties of the DCNP. Four different methodologies: time-dependent HF and time-dependent DFT method with B3LYP, LC-BLYP, and CAM-B3LYP potentials were used to compute the optical absorption spectra of DCNP. Influence of solvent on molecular electronic structure was studied within the C-PCM model. It predicts the DFT/B3LYP methodology as the best one to compute the NLO properties of the DCNP. The computed HOMO and LUMO orbitals show evidence that the ground state of the molecule is located at its aromatic part. The discussion of charge transfer during the excitation process for the transition S0-S1 was performed. The charge transfer parameter calculated in vacuum and in solvent gives the evidence that the solvent environment weakly enhance the molecular charge transfer. It confirms the tendency of an occurrence of the intermolecular charge transfer in DCNP which is crucial for its hyperpolarizability magnitude. It was proved that the second-order susceptibility corresponding to SHG may be calculated for host-guest polymer/DCNP composite using the simple oriented gas model and the rigorous local field approach should not necessarily be applied.

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“…The estimated value of ρ th 5.3 mJ∕cm 2 corresponds to the DFB lasing threshold (the conditions for the lasing wavelength were set at λ las 630 nm). As demonstrated by the work in [17], it was crucial for the DCNP crystal emission to have trap states, in which the emission occurs exactly in the spectral region covered by the stimulated emission. As was reported in [15], no stimulated emission occurs in diluted solutions of DCNP; therefore, the DCNP micro-and nanocrystals are necessary to enable the stimulated emission.…”

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Distributed feedback and random lasing in DCNP aggregates dispersed in a polymeric layer

2015

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Here, we report on the realization of random lasing (RL) and distributed feedback (DFB) lasing in a layer of luminescent 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP) organic nonlinear optical dye that has been dispersed in a poly(methyl methacrylate) (PMMA) matrix. The RL phenomenon appears due to the presence of spontaneously formed micro- and nano-crystals of DCNP in the bulk of the PMMA during the sample preparation. DFB can be realized in an optical system by using degenerated two-wave mixing in the pumping beams. The period of the interference pattern can be easily changed by changing the intersection angle of the pumping beams, resulting in a real time, fully reversible method of DFB lasing emission tuning. Because of the two neighboring stimulated emission bands of DCNP, it is possible to tune the lasing wavelength over a long range of about 65 nm.

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On the origin of fluorescence emission in optically non-linear DCNP crystals

Cited by 10 publications

References 18 publications

Environment‐Sensitive Behavior of DCNP in Solvents with Different Viscosity, Polarity and Proticity

Environment‐Sensitive Behavior of DCNP in Solvents with Different Viscosity, Polarity and Proticity

First Principle Calculations of the Electronic and Vibrational Properties of the 3-(1,1-Dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole Molecule

Distributed feedback and random lasing in DCNP aggregates dispersed in a polymeric layer

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