Efficient Bilayer Light-Emitting Diode Based on Distyrylarylene-Containing Polymers: Numerical and DFT Simulation

In this article, we report a combined experimental and theoretical study on the optoelectronic properties of two semi-conducting polymers containing different $\pi $ -conjugated sequences [distyrylphenylene (P-DSP) and distyrylbithiophene (P-DSBT)]. Theoretical calculations were conducted, based on time-dependent density functional theory and Marcus theories, to predict the optical, electronic, and charge transport properties of the studied polymers. These results were compared with the experimental ones measured using UV–vis and photoluminescence (PL) spectroscopies. The P-DSBT polymer shows good absorption with a maximum absorption wavelength of 426 nm and a green emission with a maximum wavelength of 508 nm. Besides, the calculated characteristics showed that P-DSBT has better electron and hole mobilities of $7.9\times 10^{-6}$ cm $^{-2}\,\,\text{V}^{-1}\,\,\text{s}^{-1}$ and $3.4\times 10^{-6}$ cm $^{-2}\,\,\text{V}^{-1}\,\,\text{s}^{-1}$ , respectively. A numerical simulation of ITO/polymer/Al device using the Silvaco Tecad simulator was reported and fitted to the experimental data and the results reveal an excellent overlap with the experimental ones. Moreover, the simulation of ITO/polymer/Alq₃/Al bilayer organic light-emitting diode (OLED) has been performed and electrical behavior enhancement was evidenced compared with the monolayer device with a maximum current decrease from 9 to 49 mA, using P-DSBT polymer.