Polarity- and Pressure-Induced Emission from a Benzophenone-Based Luminophore

Since strong polarity usually causes emission quenching, materials with polarity-induced emission (PIE) are rarely reported despite their important applications in polar environments. Herein, an N-phenylcarbazole-substituted benzophenone derivative (BP-3-Cz) with a twisted electron donor–acceptor (D–A) structure is synthesized. The incorporation of heteroatoms into the twisted π-conjugated D–A backbone simultaneously endows BP-3-Cz with obvious polarity- and pressure-induced emission. Spectral analysis, X-ray diffraction, differential scanning calorimetry, and quantum chemical calculation results confirm that BP-3-Cz has special optical features related to the molecular conformation change and excited state turning to planarized intramolecular charge transfer with an increase in polarity or applied pressure. These findings contribute to the understanding of the PIE mechanism and the design of new PIE materials.