Hybrid organic–inorganic perovskites as microwave radiation switches

Abstract

Hybrid organic–inorganic perovskites are an intensively growing class of functional materials that attract much attention due to their various practical and important functionalities. In this paper, we show the ability of two hybrid perovskites, namely CH₃NH₃PbI₃ and (C₅H₁₁NH₃)₂PbI₄, to act as phase transition (PT) microwave switches. Microwave switching was studied as a consequence of PTs which occur at technologically attractive temperatures – slightly above room temperature: 330 K for CH₃NH₃PbI₃ and 320 K for (C₅H₁₁NH₃)₂PbI₄. It was found that, at selected frequencies, (C₅H₁₁NH₃)₂PbI₄ is characterized by a very high transmission value of −0.4 dB which changes to −4.4 dB upon transition to a high-temperature phase. On the contrary, the transmission of CH₃NH₃PbI₃ at room temperature is deficient (−25 dB) and increases just slightly upon transformation into a high-temperature phase. The microwave absorption changes by 38% for (C₅H₁₁NH₃)₂PbI₄ and by 0.6% for CH₃NH₃PbI₃ at selected frequencies. Notably, absorption in (C₅H₁₁NH₃)₂PbI₄ changes from 9.9% at room temperature to 48.2% above the temperature of the PT, which is a five-fold increase. Our measurements show that CH₃NH₃PbI₃ is rather suitable for application as microwave absorber, while (C₅H₁₁NH₃)₂PbI₄ can be efficiently used as an active material in microwave switches.