Theoretical study on photophysical properties of multifunctional star-shaped molecules with 1,8-naphthalimide core for organic light-emitting diode and organic solar cell application

A series of D-p-A star-shaped small molecules with 1,8-naphthalimide fragments as core and different electron-rich aromatic heterocycles as end groups have been designed to explore their optical, electronic, and charge transport properties as organic light-emitting diode (OLED) and organic solar cell (OSC) materials. The frontier molecular orbitals analysis has turned out that the molecules can lower the material band gap and extend the absorption spectrum toward longer wavelengths. The calculated results showed that their optical and electronic properties are affected by the different end groups and p-bridges. Our results reveal that the molecules under investigation can serve as OSC donor materials as well as luminescent materials for OLEDs. In addition, they are expected to be promising candidates for hole and/or electron transport materials. We have also predicted the mobility of designed molecule with better performance in two different space groups. On the basis of investigated results, we proposed a rational way for the design of charge transport and luminescent materials for OLEDs, as well as donor materials in OSCs simultaneously.