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Substitutional effect of different bridging groups on optical and charge transfer properties of small bipolar molecules for OLEDs
Author(s) -
Waqas Ahmad,
Bibi Shamsa,
Rehman Shafiqur,
Afzal Sufian,
Yaseen Muhammad,
Shoaib Muhammad,
Saeed Ushna,
Da Ming Wang
Publication year - 2019
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.4000
Subject(s) - chemistry , triphenylamine , density functional theory , molecular orbital , oled , time dependent density functional theory , intramolecular force , homo/lumo , molecule , excited state , singlet state , absorption spectroscopy , acceptor , photochemistry , computational chemistry , atomic physics , stereochemistry , organic chemistry , physics , layer (electronics) , quantum mechanics , condensed matter physics
In this work, a series of eight different bipolar molecules were designed and calculated using density functional theory (DFT) and time‐dependent functional theory (TD‐DFT) for organic light emitting diodes (OLEDs) as efficient luminescent and charge transfer materials. The eight donor‐π‐donor type small molecules (D1‐D8) were composed of triphenylamine (TPA) donor (D) unit connected to 1,8‐naphthalimides (NI) acceptor (A) unit though different π ‐conjugated or R‐groups (as π ‐spacer). The effect of substitutions made in π‐spacer was investigated on optical, electronic, and stability properties. This calculation analysis showed that different substitutions in π‐spacer resulted smaller Eg (range from 1.63 to 2.00 eV), broader absorption with the lowest excitation energy covering both visible and near infrared regions of solar spectrum, especially D3, D4, D5, and D6 molecules. The analyses of local densities of states, frontier molecular orbitals, and natural population analysis of orbitals revealed that studied molecules exhibited π‐π* electronic transitions of absorption in singlet excited states, but D5 and D6 also show intramolecular charge transfer (ICT) characteristics. The study of chemical indices, molecular electrostatic potential (MEP) surfaces, and charge transfer properties turned out that D4, D5, and D6 are expected to show good potential for luminescent and hole transport materials in the favor of OLEDs.