Portable Smartphone-Enabled Single-Drop Sensors Based on CsPbX ₃ (X = Cl, Br) Perovskite Composite Nanofiber Membranes

Traditional detection methods usually use a spectrometer, which requires a professional tester to operate and is not convenient to carry around. Herein, we designed a 5G smartphone-based portable test sensor that uses a CsPbBr 3 composite fibrous membrane prepared by a one-step in situ growth method as the test paper, and the test is realized by taking pictures with the smartphone. This portable detection method requires only one drop of liquid to be detected (<25 μL), which is superior to many detection systems that require a large amount of liquid to be detected (>1 mL). Moreover, the detection sensitivity can reach 0.1 ppm, which is more sensitive than the CsPbBr 3 composite fiber membrane prepared by the conventional encapsulated method. In addition, this CsPbBr 3 composite fiber membrane is reusable and can still achieve highly sensitive detection with a single drop after 100 uses. This smartphone-based portable test sensor is small in size and easy to use and can be used at home or outdoors anytime and anywhere.