Solvent and Steric Hindrance Effects of Bulky Poly(9,9-diarylfluorene)s on Conformation, Gelation, Morphology, and Electroluminescence

Abstract

Clarification of the solvent effects of bulky π-conjugated polymers on the conformation behavior and morphology evolution of the chain from solution to thin film is the main prerequisite for the molecular design of printable polymer light-emitting materials. Here, three bulky poly(9,9-diarylfluorene)s (PFs) with the steric hindrance effect are synthesized to examine gelation behaviors, β-phase conformation, film morphology, and electroluminescence (EL) spectra in three solvents. Their gelation behaviors occur in 1,2-dichloroethane (DCE) of high concentrations, featuring emission bands of ≈470 nm as well as the β-phase conformation. Bulky PFs also exhibit different solvent effects on the morphology and green emission bands. Compared with other bulky PFs, poly(spirofluorenexanthene)s have obvious advantages in terms of the solvent-independent emission, high quantum yield, and air-stable photoluminescence, as well as the EL spectra. Poly(SFX) will be potential components for the formula of optical inks in printed electronics.