Highly Crystallized Tin Dioxide Microwires toward Ultraviolet Photodetector and Humidity Sensor with High Performances

The rapid development of artificial intelligent and internet of things calls for high-performance multifunctional devices for synchronous detection of a wide variety of environmental signals, such as gas, light, and humidity. Herein, highly crystallized tin dioxide (SnO 2 ) microwires (MWs) with low density of point defects are synthesized by the chemical vapor deposition method and constructed into a multifunctional device for photo and humidity sensing. The device shows excellent photoelectric performances, for example, ultralow dark current of ≈10 −13 A, ultrahigh on–off ratio of >10 7 , UV/visible rejection ratio of R 300 nm / R 400 nm > 10 7 , specific detectivity ( D *) of 1.16 × 10 15 Jones, linear dynamic range (LDR) of 152 dB, high responsivity of 18 A W −1 , and fast photoresponse speed of t rise / t decay = 2.7 µs/2.5 ms at 5 V bias. Furthermore, the p-CuI/n-SnO 2 heterojunction shows outstanding self-powered properties, such as responsivity of 8.98 mA W −1 , specific detectivity of 1.98 × 10 12 Jones and LDR of 106 dB at 0 V bias. Additionally, the SnO 2 MWs also show high sensitivity to ambient humidity changes. Therefore, the SnO 2 MWs show high potential for multifunctional applications, such as UV photodetector and humidity sensor.