Ultrasensitive organic-inorganic nanotube thin films of halogenated perovskites as room temperature ammonia sensors

•Comparative study of ammonia sensing carried out for MAPbI3 and MAPbI3−xClx thin films.•The MAPbI3−xClx thin films sensor exhibits a high response which is ~13 times larger than the MAPbI3 sensor.•The MAPbI3−xClx sensor exhibit dense nanostructured tube like structure and large diffusion length of charge carriers.•The MAPbI3−xClx sensor show highly selective and stable ammonia sensing performance than the MAPbI3 sensor. Recently organic-inorganic halide perovskites like MAPbX3 (XBr, Cl, I), are being investigated as a substitute to commonly used metal oxide semiconductor-based sensors for the detection of various volatile organic compounds and toxic gases at room temperature. The present work provides detailed insights into chlorine halide incorporation on the ammonia sensing performance of the most popular MAPbI3 (MAPI) perovskite thin films. Here, we shown that the MAPbI3−xClx (MAPIC) sensor exhibits a high response of 591%, nearly13 times larger than the MAPI sensor for 10 ppm of ammonia exposure at room temperature. This work demonstrates excellent potential of MAPIC as an ultra-sensitive, stable and reversible NH3 sensor vis-à-vis MAPI sensor for early detection of NH3. The proposed sensing mechanism suggests that by engineering the morphology at the nanoscale and doping induced excellent charge carrier diffusion length could enhance ammonia sensor responsivity.