Defect-Induced Gas-Sensing Properties of a Flexible SnS Sensor under UV Illumination at Room Temperature

Abstract

Tin sulfide (SnS) is known for its effective gas-detecting ability at low temperatures. However, the development of a portable and flexible SnS sensor is hindered by its high resistance, low response, and long recovery time. Like other chalcogenides, the electronic and gas-sensing properties of SnS strongly depend on its surface defects. Therefore, understanding the effects of its surface defects on its electronic and gas-sensing properties is a key factor in developing low-temperature SnS gas sensors. Herein, using thin SnS films annealed at different temperatures, we demonstrate that SnS exhibits n-type semiconducting behavior upon the appearance of S vacancies. Furthermore, the presence of S vacancies imparts the n-type SnS sensor with better sensing performance under UV illumination at room temperature (25 °C) than that of a p-type SnS sensor. These results are thoroughly investigated using various experimental analysis techniques and theoretical calculations using density functional theory. In addition, n-type SnS deposited on a polyimide substrate can be used to fabricate high-stability flexible sensors, which can be further developed for real applications.

Roadmap on printable electronic materials for next-generation sensors

“…Developing synthetic methods and deposition techniques that enhance performance and signal reproducibility in analytical measurements is crucial and requires significant improvements. Indeed, it is well known that film thickness impacts on sensing performance, especially on 2D structures [513]. In fact, the number of layers affects the electronic properties of 2D materials.…”

Flexible/wearable resistive gas sensors based on 2D materials

“…In particular, many flexible TMD-based sensors have been developed with the aim of detecting NO 2 gas, due to the importance of this gas in various industries. 42,[104][105][106][107][108][109][110] For instance, a flexible room temperature sensor was fabricated by the direct growth of vertically-aligned 2D SnS 2 via atomic layer deposition (ALD) on a plastic substrate. The ALD process was able to generate a uniform coating of SnS 2 over the substrate.…”

Multistep design simulation of heterojunction solar cell architecture based on SnS absorber

“…The aforementioned results indicate that a significant reduction in interfacial recombination can be achieved by decreasing the hole density at the adjacent surface region of the SnS absorber layer. Various synthesis methods have reported a broad range of hole concentration (ranging from ∼10 12 to 10 18 cm −3 ) in the SnS absorber thin film [33,73,76]. However, if the absorber layer has uniformly low hole density, it leads to the generation of a smaller built-in voltage, resulting in an overall decrease in performance.…”