Enabling Wholly Aromatic Triphenylamine‐Based Polyimides to Realize Bathochromic Emission

Abstract The development of wholly aromatic polyimides (Ar‐PIs) in the field of fluorescence material has long been hindered by the charge‐transfer complex (CTC) effect, typically causing weak or non‐detectable fluorescence intensity. Few studies have aimed to reduce the CTC effect through molecular design, enabling Ar‐PIs to exhibit blue to yellow emission in solid films with high quantum efficiency (Φ _PL). However, current complex molecular designs pose inherent limitations for further reducing the emission energy gap toward the orange‐red regions. To address this issue, in this work, a series of triphenylamine (TPA)‐based fluorescence diimides with various electron‐donating/extended π‐conjugation pendant groups are strategically designed and synthesized to probe their emissive behaviors and the corresponding Ar‐PIs properties. Notably, along a series of new Ar‐PIs, PI‐TPE, PI‐TPPA‐TPE, and PI‐TPPA exhibit a systematic bathochromic shift emission at 540, 598, and 608 nm, respectively, in the film state, where PI‐TPPA and PI‐TPPA‐TPE fill up and realize the full‐spectrum emission by utilizing the TPA architecture.