CsPbI₃NC-Sensitized SnO₂/Multiple-Walled Carbon Nanotube Self-Assembled Nanomaterials with Highly Selective and...

It is an effective strategy to enhance the sensitivity of semiconductor metal oxides (SMOs) being sensitized with CsPbI₃ nanocrystals (NCs) by adjusting the heterostructure between CsPbI₃NC and SMO nanomaterials. In this work, for the first time, a porous 3D multiple-walled carbon nanotube (MWCNT) network uniformly coated with SnO₂ quantum nanoparticles (QNPs) and CsPbI₃ nanocrystals were prepared via a simple solvent vapor-induced self-assembly method. The fabricated CsPbI₃NC-SnO₂QNP/MWCNT nanocomposite with vapor-induced self-assembly exhibits superior stability against the moisture as well as an excellent sensing response. The results imply that the rational design of the metal halide perovskite NC/SMO heterostructure can not only improve the stability but also meet the requirements of sensing application. The self-assembled SnO₂QNP/MWCNT can facilitate the dispersion of small-sized nanoparticles and efficaciously prevent the detachment of CsPbI₃NC. Compared with pristine SnO₂QNP and SnO₂/MWCNT sensors, the CsPbI₃NC-modified SnO₂QNP/MWCNT nanostructure exhibited a remarkable sensitivity of 39.2 for 0.2 ppm NH₃, rapid response/recovery time of 17/18 s, and excellent selectivity towards NH₃. In particular, we applied machine learning methods, including principal component analysis (PCA) and support vector machines (SVMs), to analyze the sensing performance of the CsPbI₃NC-SnO₂QNP/MWCNT sensor and found that the combined effects of CsPbI₃NC-SnO₂QNP/MWCNT heterointerfaces contributed to the improvement of selectivity of sensors. The excellent NH₃ for sub-ppm level concentration is ascribed to the high sensing activity of the CsPbI₃ NC-based heterojunction. This work may not only enrich the family of high-performance breath detection materials but also provide a good example for designing reasonable composite materials with specific properties in the field of metal halide perovskite/SMO heterojunctions.