Shedding light on structural, optoelectronic and charge transport properties of PPV stereoisomers for multilayer OLED application: A first principle computational studies

Abstract In the past few years, π-conjugated polymers, especially PPV derivatives, have been target of intense studies due to their fascinating properties. In this paper, structural, vibrational and optoelectronic properties of a PPV-type π-conjugated polymer (BPAEt 2 -PPV) displaying three different stereoisomers: Z-Z , E-E and Z-E have been investigated based on density functional theory (DFT) calculations. Theoretical studies were performed in order to justify the chemical structure and also to predict polymer-structure property relationships. Based on TD-DFT and Marcus theories, we have explored the impact of structural configuration on optoelectronic properties and charge mobility. As a result, E -E structure shows a better absorption with a maximum wavelength λ abs max = 407.52 nm mainly composed by π → π* electronic transitions and a gap energy equal to 3.39 eV. Similarly, all structures shows a blue emission properties with a best maximum wavelength of λ emiss max = 439.18 nm for E -E structure. Furthermore, the theoretical results showed that the electron mobility for E-E structure was high as compared with others configurations with an electron intermolecular charge hopping K et  = 8.54 10 13 . While the better hole transport is found for Z -Z structure with a hole intermolecular charge hopping K ht  = 6.21 10 13 . Finally, a numerical simulation, of an organic light emitting diode device using Silvaco TCAD software has been performed and a good enhanced in electrical properties are obtained for E -E configuration compared to Z -Z and Z-E structures with a turn-on voltage of 6.2 V. Based on these interesting results, we have deduced that all structures could be exploited as an active layer in organic light emitting diode.