Room-Temperature Dielectric Switching in a Host-Guest Crown Ether Inclusion

Host-guest compounds based on crown ether are promising candidates for switchable dielectric materials, holding great potential for the fields of sensing, information storage, and electronics. However, their phase transition temperature (Tp) is commonly shown at very low, seriously limiting their further developments. Herein, using the 'momentum matching theory', we have successfully designed a room-temperature crown ether based switchable dielectric material, 3-methoxyanilinium-18-crown-6 bis(trifluoromethanesulfonyl)ammonium) ([(3-methoxyanilinium)(18-crown-6)][TFSA]) (1). Compared with the [C7H10NO-(18-crown-6)][PF6] (Tp = 180 K), the introduction of larger TFSA anion not only brings new kind of C−H···O−S interactions between host cations and ordered TFSA anions to affect the crystal stacking but also enhances the energy barrier of anionic movements, resulting in the occurrence of phase transition at a higher temperature of about 308 K. Such a large Tp enhancement of 128 K is rarely reported in host-guest crown ether inclusion. The switchable dielectric behavior between high and low dielectric states suggests a great potential for room-temperature bistable dielectric switches. This work paves the way towards the design of crown ether inclusion dielectric switches for a wide range of applications such as sensors and switches near room temperature.