The DFT study on non‐conjugated polymer host materials based on styrene derivatives for phosphorescent polymer light‐emitting diodes

A series of poly(4,4‐vinyltriphenylamine) based non‐conjugated polymer as host molecules are designed and studied by density functional theory. The results show that the substituent has a great influence on the properties of polymer. The parent molecule directly linked para ‐carbazole, β‐pyrrole and triphenylamine are favorable to hole injection, and para ‐carbazole could significantly increase E T of the host molecules. The large changes of structural parameters between the lowest triplet state and ground state can cause the decrease of E T . Moreover, parent molecule directly linked carbazole and triphenylamine units possess strong intramolecular charge transfer and low singlet and triplet energy difference (∆ E ST ). The calculated results also show that all designed host molecules are suitable for green emitter by comparing with the E T . S 1  → S 1 and T 1  → T 1 energy transfer mechanism between host and guest is thermodynamically feasible. In addition, host–guest model is built to study the charge transfer nature, and the results indicate that a good intermolecular charge transfer can be achieved between host and guest materials. In the designed host molecules, the N atom of parent molecule linked para ‐carbazole substituent shows a great potential for the green phosphorescent polymer light‐emitting diodes . Copyright © 2015 John Wiley & Sons, Ltd.