Inorganic Halide Perovskite Electromagnetic Wave Absorption System with Ultra‐Wide Absorption Bandwidth and High Thermal‐Stability

Abstract Halogen perovskite, a novel semiconductor material that has gained momentum in the energy sector, has also emerged in the field of electromagnetic wave (EMW) protection. Inorganic halogen perovskites are expected to perform well owing to their excellent stability and dielectric properties. In this study, a CsPbBr 3 /Carbon nanotubes (CNTs) composite is designed using a convenient antisolvent method. In addition to an ultrawide absorption bandwidth (5.56 GHz) and ultrahigh absorption strength (|Reflection loss| = 51.74 dB), the composite shows excellent thermal stability and environmental tolerance. In an air environment, its EMW‐absorbing performance can be maintained at a high level at a temperature below 400 °C. CNTs build an efficient conductive network between CsPbBr 3 to enhance the conduction loss of the composite, while it brings more defects and vacancies to the surface of CsPbBr 3 to form electrical polarization centers which improving the polarization loss of the composite. This is the first study of the application of inorganic halogen perovskites in the field of EMW absorption. The excellent EMW‐absorbing performance and stability of CsPbBr 3 /CNTs demonstrate the great potential of inorganic halogen perovskites in the field of EMW absorption and provide a valuable reference and feasible strategy for regulating and controlling the EMW‐absorbing performance of perovskite materials.