Multiscale Humidity Visualization by Environmentally Sensitive Fluorescent Molecular Rotors

Yanhua Cheng; Jianguo Wang; Zijie Qiu; Xiaoyan Zheng; Nelson L C Leung; Jacky W Y Lam; Ben Zhong Tang

doi:10.1002/adma.201703900

Multiscale Humidity Visualization by Environmentally Sensitive Fluorescent Molecular Rotors

Adv Mater. 2017 Dec;29(46). doi: 10.1002/adma.201703900. Epub 2017 Oct 16.

Authors

Yanhua Cheng^{1

2}, Jianguo Wang^{1

2}, Zijie Qiu^{1

2}, Xiaoyan Zheng¹, Nelson L C Leung^{1

2}, Jacky W Y Lam^{1

2}, Ben Zhong Tang^{1

2

3}

Affiliations

¹ Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute of Molecular Functional Materials, State Key Laboratory of Nanoscience, Division of Biomedical Engineering and Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
² Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST-Shenzhen Research Institute, Shenzhen, 518057, China.
³ Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China.

PMID: 29044736
DOI: 10.1002/adma.201703900

Abstract

Building humidity sensors possessing the features of diverse-configuration compatibility, and capability of measurement of spatial and temporal humidity gradients is of great interest for highly integrated electronics and wearable monitoring systems. Herein, a visual sensing approach based on fluorescent imaging is presented, by assembling aggregation-induced-emission (AIE)-active molecular rotors into a moisture-captured network; the resulting AIE humidity sensors are compatible with diverse applications, having tunable geometries and desirable architectures. The invisible information of relative humidity (RH) is transformed into different fluorescence colors that enable direct observation by the naked eyes based on the twisted intramolecular charge-transfer effect of the AIE-active molecular rotors. The resulting AIE humidity sensors show excellent performance in terms of good sensitivity, precise quantitative measurement, high spatial-temporal resolution, and fast response/recovery time. Their multiscale applications, such as regional environmental RH detection, internal humidity mapping, and sensitive human-body humidity sensing are demonstrated. The proposed humidity visualization strategy may provide a new insight to develop humidity sensors for various applications.

Keywords: aggregation-induced emission; fluorescent sensors; humidity visualization; molecular rotors.