Tagare, J.Ulla, H.Satyanarayan, M.N.Sivakumar, S.2026-02-052018Journal of Luminescence, 2018, 194, , pp. 600-609222313https://doi.org/10.1016/j.jlumin.2017.09.020https://idr.nitk.ac.in/handle/123456789/25280In this work, two star-shaped small conjugated materials, namely tris(4-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl) amine (PIPTPA) and tris(4-(1-p-tolyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)amine (PITTPA) with donor-?-acceptor (D-?-A) structures, were designed and synthesized by combining three phenanthroimidazole arms into an triphenylamine core. A detailed photophysical, thermal, electrochemical and related properties were systematically studied. Furthermore, theoretical calculations (DFT and TD-DFT) were performed to get a better understanding of the electronic structures. Both the materials were found to exhibit high glass transition temperatures (~ 238 °C) and high thermal stabilities with decomposition temperatures up to 298 °C. OLEDs using these materials as emissive materials showed excellent device performance (7.42 cd A?1, 5.77 lm W?1, 4.14% at 100 cd m?2) with green emission and low turn-on voltages. The results demonstrate that TPA integrated with phenthroimdazole plays an important role in the device performance. © 2017 Elsevier B.V.Electronic structureGlass transitionLightLight emitting diodesConjugated materialsDecomposition temperatureGreen emittersHigh thermal stabilityHigh-glass transition temperaturesLow turn-on voltagesPhenanthroimidazoleTheoretical calculationsOrganic light emitting diodes (OLED)