Theoretical studies of the structural, electronic, and optical properties of phosphafluorenes

Phosphafluorenes have drawn increasing attention recently in the applications of organic electronic devices due to their particular optoelectronic properties. To reveal, their molecular structures, optoelectronic properties, and structure-property relationships of the newly emerged functional, materials, an in-depth theoretical, investigation was elaborated via quantum chemical calculations. The optimized geometric and electronic structures in both ground and exited states, the mobility of the hole and electron, the absorption and emission spectra, and the singlet exciton generation fraction of these novel phosphors-containing materials have been studied by density functional theory (DFT), single excitation configuration interaction (CIS), time-dependent density functional theory (TDDFT) methods, and the polarizable continuum model (PCM). The results show that the highest occupied molecular orbitais (HOMOs), the lowest unoccupied molecular orbitais (LUMOs), triplet energies (³E_g), energy gaps (E _g), as well as some other electronic properties including ionization potentials (IPs), electron affinities (EAs), reorganization energies (λ), the singlet exciton generation fraction, radiative lifetime, and absorption and emission spectra can be easily tuned by chemical modifications of the phosphorus atom via methyl, phenyl, oxygen, sulfur, or selenium substitution, indicating that the phosphafluorenes are interesting optoelectronic functional materials, which have great potential in the applications of OLEDs, organic solar cells, organic storage, and sensors.