Enhanced blackness and solubility of polyimide via introducing propeller-shaped chromophore

Abstract

The rapid development of optoelectronic devices presents significant challenges to the comprehensive performances of black polyimide (BPI). In order to cope with these challenges, in this work, a soluble intrinsic black polyimide (TPCPPPI) is designed and synthesized through the polymerization of a new diamine (TPCPPDA) bearing tetraphenylcyclopentadienone (TPCP) chromophore with 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). The resulted TPCPPPI showed a cutoff wavelength (λcut) of 627 nm and Commission International de l'Eclairag LAB (CIE-LAB) parameter L* of 5.73. Theoretical calculation was performed with respect to the electronic transitions of TPCPPPI. The results showed that the excellent light absorption property of TPCPPPI was principally ascribed to the electronic excitation from HOMO to LUMO orbital which occurred in the chromophore unit, where the electrons chiefly moved from the aryl groups at 2- and 5-positions to the cyclopentadienone centre. Furthermore, TPCPPPI also possessed superior mechanical, electrical and thermal performance as well as outstanding solubility due to the rational structural design. This study contributes to the development of soluble intrinsic BPI with superior overall property and promotes the application of BPI in modern electronic devices.