Maxim S. Kazantsev

Highly Luminescent Solution-Grown Thiophene-Phenylene Co-Oligomer Single Crystals

Thiophene-phenylene co-oligomers (TPCOs) are among the most promising materials for organic light emitting devices. Here we report on record high among TPCO single crystals photoluminescence quantum yield reaching 60%. The solution-grown crystals are stronger luminescent than the vapor-grown ones, in contrast to a common believe that the vapor-processed organic electronic materials show the highest performance. We also demonstrate that the solution-grown TPCO single crystals perform in organic field effect transistors as good as the vapor-grown ones. Altogether, the solution-grown TPCO crystals are demonstrated to hold great potential for organic electronics.

Highly-emissive solution-grown furan/phenylene co-oligomer single crystals

Solution-processed furan/phenylene co-oligomer single crystals combine high photoluminescence quantum yield (>65%) and efficient charge transport (mobility 0.12 cm2 V−1 s−1) making them promising materials for printable organic optoelectronics.

Methyl substituent effect on structure, luminescence and semiconducting properties of furan/phenylene co-oligomer single crystals

Single crystals of furan/phenylene co-oligomers are among the most promising highly-emissive materials for applications in various optoelectronic devices. In this work, we synthesized and studied furan/phenylene co-oligomers with the same conjugated core 1,4-bis(5-phenylfuran-2-yl)benzene and methyl substituents at p- and m-positions of the terminal phenyls. The effect of substituents on the crystal packing, charge transport and luminescence of the single crystals was studied. Compared to the unsubstituted compound, the methyl-substituted co-oligomers demonstrated improved thermostability and enhanced photoluminescence, which we assign to J-aggregation resulting from the strong inclination of the molecules against the main crystal facet. The charge mobility in single crystal organic field-effect transistors decreased upon the inclination of the molecules. We conclude that the molecular tilt angle, intermolecular distances and interactions in crystals of heteroaryl-containing linear conjugated oligomers can be controlled by the introduction of end methyl groups in the appropriate positions.

Novel Anthrathiophene-Based Small Molecules as Donor Material for Organic Photovoltaics: Synthesis and Light-Induced EPR Study

Abstract A novel anthrathiophene-based compound, 1,4-bis((5-(6,11-dioxoanthra[2,1-b]thiophene-2-yl)thien-2-yl)ethynyl)-2,5-bis(octyloxy)benzene, was synthesized and characterized. The optical absorption spectrum of the synthesized compound in film is strongly red-shifted as compared to the solution spectrum. The energies of frontier orbitals measured by cyclic voltammetry show that this compound can act as electron donor in a composite with the widely used fullerene derivative PCBM. This is confirmed by light-induced electron transfer from it to PCBM evidenced from light-induced EPR spectroscopy. The spectroscopic data suggest that anthrathiophene is a promising platform for synthesis of small-molecular electron donors for organic solar cells.

Long-Range Exciton Transport in Brightly Fluorescent Furan/Phenylene Co-oligomer Crystals

The design of light-emitting crystalline organic semiconductors for optoelectronic applications requires a thorough understanding of the singlet exciton transport process. In this study, we show that the singlet exciton diffusion length in a promising semiconductor crystal based on furan/phenylene co-oligomers is 24 nm. To achieve this, we employed the photoluminescence quenching technique using a specially synthesized quencher, which is a long furan/phenylene co-oligomer that was facilely implanted into the host crystal lattice. Extensive Monte-Carlo simulations, exciton–exciton annihilation experiments and numerical modelling fully supported our findings. We further demonstrated the high potential of the furan/phenylene co-oligomer crystals for light-emitting applications by fabricating solution-processed organic light emitting transistors.

CCDC 1520469: Experimental Crystal Structure Determination

Related Article: Maxim S. Kazantsev, Alina A. Beloborodova, Ekaterina S. Frantseva, Tatyana V. Rybalova, Vladislav G. Konstantinov, Inna K. Shundrina, Dmitry Yu. Paraschuk, Evgeny A. Mostovich|2017|CrystEngComm|19|1809|doi:10.1039/C6CE02565J

CCDC 1520470: Experimental Crystal Structure Determination

Related Article: Maxim S. Kazantsev, Alina A. Beloborodova, Ekaterina S. Frantseva, Tatyana V. Rybalova, Vladislav G. Konstantinov, Inna K. Shundrina, Dmitry Yu. Paraschuk, Evgeny A. Mostovich|2017|CrystEngComm|19|1809|doi:10.1039/C6CE02565J