Novel oxygen sensor based on terfluorene thin-film and its enhanced sensitivity by stimulated emission

Abstract

Ter(9,9-diarylfluorene) (TDF) neat film featuring oxygen sensing with advantages of fast response, reversibility and high efficiency is reported. The fast O₂ fluorescence quenching process (4.0 × 10¹⁰ M⁻¹ s⁻¹) is unique and is mainly due to intact amorphous morphology of the TDF film, providing ample porous sites in nature so that O₂ can travel therein freely. This, together with a large S₁–T₁ energy gap of TDF, leads to efficient O₂ sensitization, i.e. the O₂ induced S₁–T₁ intersystem crossing. The sensitivity can be further enhanced up to ∼10-fold and ∼20-fold in amplified spontaneous emission (ASE) and lasing action, respectively. The work thus demonstrated a new class of organic materials suited for high-speed, high-sensitivity oxygen sensing.