Facile synthesis of black phosphorus nanoflakes by hydrothermal method for hydrogen sensing application

This article presents a direct method of producing Black Phosphorus (BP) from red phosphorus through hydrothermal aqueous method by using Ethylene Diamine and De-Ionized water, followed by fabricating a BP-based gas sensor. This work presents a low-temperature, low-cost synthesis of black phosphorus from red phosphorus and establishes its application in a comprehensive device-level gas sensor, offering a real-world and scalable approach. Inside autoclave, due to these pressure-high temperature conditions, the red phosphorus reshapes and turns into black phosphorus, usually in the form of nanoflakes. To disintegrate the particles and increase the interaction of phosphorus with the solvent solution, the solution is treated by ultrasonic during few hours. Apparently, this is an initial effort of producing Black Phosphorous from Red Phosphorous with low-temperature synthesis, low cost with a complete device-level gas sensor implementation. Produced Black Phosphorous are characterized by X-ray diffraction, field emission scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared, XRD analysis and Tauc plot. The experiment was held using deionized (DI) water and ethylene diamine separately in this case to study their individual effects on the synthesis procedure. Additionally, a thin-film sensor is fabricated utilizing the spin coating technique, with the sensor’s electrical performance being examined through I-V measurements in 1% hydrogen gas and temperature (50–300 °C) conditions, exhibiting Schottky -type behaviour with detectable sensitivity under low concentration of hydrogen suggesting the potential use of a BP-based sensor as a low-power application.