36636-51-8Relevant academic research and scientific papers
High-triplet-level phthalimide based acceptors for exciplexes with multicolor emission
Chapran, Marian,Lytvyn, Roman,Begel, Corentin,Wiosna-Salyga, Gabriela,Ulanski, Jacek,Vasylieva, Marharyta,Volyniuk, Dmytro,Data, Przemyslaw,Grazulevicius, Juozas Vidas
, p. 872 - 882 (2019)
To provide high exciton utilization in organic light emitting diodes, phthalimide derivatives were designed and synthesized as exciplex-forming materials. Due to high triplet levels (2.92–3.11 eV) and ionization potentials (7.18–7.29 eV), the developed phthalimide derivatives were found to be not only appropriate accepting materials for the formation of different color exciplexes but also as bifunctional materials with a satisfactory hole and exciton-blocking abilities. Solid-state blends of the synthesized phthalimides as acceptors and a carbazole containing donors showed exciplex emission. Bimolecular blends exhibited multicolor exciplex emission which covered a visible spectrum from sky-blue to red colors, depending on the donor used. However, the photoluminescence quantum efficiencies of the studied exciplex-forming systems were found to be sensitive to the molecular design of the phthalimides. Acceptor with para-substituted phthalimide showed better exciplex-forming properties in comparison to other compounds. Exciplex-forming blend of (2-(4-benzoylphenyl)isoindoline-1,3-dione) as an acceptor and 1,3-di(9H-carbazol-9-yl)benzene (mCP) as a donor showed the most efficient sky-blue emission with small singlet-triplet splitting (0.06 ± 0.03eV). Such exciplex-forming molecular mixture was implemented as the light-emitting material in the sky-blue organic light emitting diodes which showed the brightness of 2500 cd m?2 and maximum external quantum efficiency of 2.9% due to the employment of both singlet and triplet excitons.
A conformational study of aromatic imide compounds. Part 1. Compounds containing diphenyl ether and benzophenone moieties
Aimi, Keitaro,Fujiwara, Toshihiro,Ando, Shinji
, p. 405 - 416 (2002)
An attempt was made to estimate the dihedral angles φ, ψ, ω1 and ω2, of bis(4-hydroxyphthalimide)s (BHPI) and bis-(phenylphthalimides)s (BPI) having diphenyl ether or benzophenone linkages at the center of molecules using solid-state 13C CP/MAS NMR and ab initio nuclear shielding calculations. The TOSS and TOSS & DD pulse sequences were performed in the NMR measurements to obtain exact chemical shifts of each carbon. Total energies were calculated using the B3LYP/6-31G(d) level of theory, and shielding constants were calculated using the RHF/6-31G(d) level of theory for diphenyl ether and benzophenone by varying the angles of φ, ψ from 0 to 180° at intervals of 10°. The comparison of nuclear shielding calculations between RHF/6-31G(d) and B3LYP/6-311 +G(2d,p) levels of theory indicates that RHF/6-31G(d) has sufficient reliability for calculating shielding constants of diphenyl structures. Since the nuclear shieldings are displaced depending on the dihedral angles, the dihedral angles of BHPIs and BPIs can be estimated by comparing the experimental chemical shifts with the calculated shielding constants. The BHPIs, BPIs and a related polyimide ODPA/ODA were estimated to have symmetric conformations having identical φ and ψ and identical ω1 and ω2.
