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 (BPAEt2-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 λabsmax= 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 λemissmax= 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 Ket = 8.54 1013. While the better hole transport is found for Z-Z structure with a hole intermolecular charge hopping Kht = 6.21 1013. 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.
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•Experimental and theoretical studies of different stereoisomers are performed.•DFT calculations were conducted as first principle computational studies.•Isomerization strongly affects the optoelectronic properties of BPAEt2-PPV polymer.•E-E stereoisomer shows the best optoelectronic and charge transport properties.•Multilayer OLED based on E-E structure shows best efficiency.