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A Perylene Bisimide‐Contained Molecular Dyad with High‐Efficient Charge Separation: Switchability, Tunability, and Applicability in Moisture Detection
Author(s) -
Wang Zhaolong,
Wang Gang,
Chang Xingmao,
Liu Ke,
Qi Yanyu,
Shang Congdi,
Huang Rongrong,
Liu Taihong,
Fang Yu
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201905295
Subject(s) - perylene , materials science , fluorophore , fluorescence , relative humidity , photochemistry , diimide , photoinduced electron transfer , charge (physics) , optics , chemistry , physics , thermodynamics , quantum mechanics
Designing novel fluorophores with nonplanar structure and environmental sensitivity is of great significance for the development of high‐performance film‐based fluorescent sensors. Herein, a unique pentiptycene (P) and perylene bisimide (PBI)‐contained fluorescent dyad (P‐PBI‐P) displaying a switchable and tunable charge separated state is reported. It is demonstrated that this symmetrical and dumbbell‐like molecular dyad shows a greater extent of photoinduced intramolecular electron transfer than the asymmetrical dyad, P‐PBI. In addition, the charge separated state (P + ‐PBI − ‐P/P‐PBI − ‐P + ) of the fluorophore is super susceptive to solvent polarity, allowing sensitive detection of water content in organic liquids. Based on the finding, two P‐PBI‐P‐based fluorescent humidity sensors are fabricated, and they both show linear responses to air humidity within a range of at least 6.3% to 100% (relative humidity, RH). The response time is less than a few seconds, and the recovery time less than 1 min. Importantly, almost no hysteresis is found during a cyclic humidification and dehumidification test within the whole RH range studied. The superior performance of the humidity sensors based on the modulation of the charge separated state of a fluorophore constitutes an effective way for designing high‐performance film‐based fluorescent sensors.