Photo- and electroluminescence of new organic semiconductors

The results of investigation of the luminescence under photo- and electroexcitation for four new compounds are presented. The spectral properties and photoluminescence are studied in ethanol, chloroform solutions and in films formed by thermovacuum deposition (TVD). The phosphorescence of compounds is investigated in ethanol at 77K temperature. The phosphorescence times of molecules are given. The electroluminescence is obtained in multilayered structure ITO/PEDOT/NPD/L /Ca/Al. It is shown, that spectral region of the photoluminescence of TVD films and electroluminescence coincide. Relations of electroluminescence efficiency with molecule structure, photoluminescence quantum yield and possibility of thermally activated delayed fluorescence are discussed

Fluorescene quenching of some organic compounds with nitrotoluene vapor

Sensor properties of poly(9,9-di-n-octyl-2,7-fluorene) (PFO), poly[9,9-dioctylfluorenyl-2,7-diyl] end capped with dimethylphenyl (ADS), polyvinylcarbazole (PVK), N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]4,4′-diamine (TPD), and 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD) on the presence of nitrotoluene vapor are studied. Sensor properties of fluorophores doped into different materials are investigated using the method of fluorescence quenching due to formation of the non-fluorescent complex between the fluorophore and nitrotoluene molecules

Spontaneous and stimulated emission of thin-film polymer structures in the presence of nitrotoluene vapour

The features of spontaneous and stimulated emission of polyfluorenes, polyvinylcarbazole, and low-molecular-weight electron-donor compounds incorporated into various materials are studied in the presence of nitrotoluene vapour. Lasing in planar thin-film waveguides is achieved. The dynamics of the lasing spectra of a thin-film optical chemical sensor is presented. It is shown that the response time of the sensor in the lasing regime is 30 s before the lasing intensity decreases by 50% from the initial level

Spectral‑luminescent and electroluminescent properties of charge‑transfer systems based on electron‑donating diphenylamine derivatives and acceptors of dibenzothiophene sulfone and phenanthridine

Spectral characteristics and luminescence under the photo- and electro-excitation of substituted dibenzthiophene sulfone and phenanthridine were studied in this paper. Diphenylamines are substituents introduced in the 2nd and 7th positions (linear configuration) or the 3rd and 6th positions (angular configuration) of dibenzthiophene sulfone or phenanthridine. All molecules show delayed fluorescence, both in solutions and films produced by thermal vacuum deposition. The value of the energy gap between the S1 and T1 states has been estimated and is shown to depend not only on the spatial arrangement of the fragments among themselves (linear or angular), but also on the nature of the substituent in diphenylamine. The highest electroluminescence brightness was found for the molecules, in which triplet levels are involved, both through the process of triplet-triplet annihilation and through thermally activated delayed fluorescence

Preparation of nanocomposites based on PMMA and CdSe, CdSe/CdS quantum dots

Nanocomposites based on PMMA and CdSe, CdSe/CdS quantum dots were developed. Quantum dots (QD) of CdSe, CdSe/CdS with sizes from 2.0 nm to 4.0 nm were obtained by deposition in various media. The photoluminescence range for the obtained QDs was from 480 to 628 nm. The results of the study show that the photoluminescent properties of CdSe, CdSe/CdS quantum dots introduced into the PMMA matrix are retained. The resulting nanocomposites can be used to create solid-state laser active media

Thermally activated delayed fluorescence in dibenzothiophene sulfone derivatives: Theory and experiment

The photophysical properties are calculated for the dibenzothiophene sulfone substituted with various electron donor moieties:3,7-bis[N,N-di(4-tert-butylphenyl)amino]dibenzothiophene-S,S-dioxide (1L), 2,8-bis[N,N-di(4-tert-butylphenyl)amino]dibenzothiophene-S,S-dioxide (1A), and 2,8-bis[N,N-di(4 methoxyphenyl)amino]dibenzothiophene-S,S-dioxide (2A). It is shown that the linear arrangement of the electron donor substituents relative to the dibenzothiophene sulfone acceptor turns compound (1L) an efficient prompt fluorescent emitter, while the angular arrangement of the substituents decreases the efficiency of prompt fluorescence, but increases the efficiency of thermally activated delayed fluorescence (TADF). Replacing the auxiliary tert-butyl groups in the donor moieties by methoxy groups leads to an increase in kISC and kRISC. OLEDs are made with the studied compounds