Transparent–Flexible–Moldable Low-Temperature Thermometer Constructed by Harnessing Vibration-Induced Emission of Dihydrophenazine in Polydimethylsiloxane

Developing an easy-molding luminescent thermometer for low-temperature monitoring is significant in science and regular life. By combination of vibration-induced emission (VIE) and thermal expansion mechanisms, a ratiometric fluorescent polymeric thermometer is manufactured by dispersing bent N,N′-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC) into moldable poly(dimethylsiloxane) (PDMS) for low-temperature detection from 177 to 277 K. Preliminary studies have shown that temperature-dependent emission can be visually detected and ratiometrically quantified. Moreover, this transparent–flexible thermometer can be not only coated on substrates but also molded into desired shapes. This work provides an innovative fabrication method for developing low-temperature ratiometric fluorescent polymeric sensors with visualization, transparency, flexibility, and moldability.