Engineering of SnO2-Graphene Oxide Nano-Heterojunctions for Selective Room-temperature Chemical Sensing and Optoelectronic Devices

TL;DR

This paper reports the engineering of SnO2-graphene oxide nano-heterojunctions that enable highly selective, room-temperature chemical sensing of volatile organic compounds and have potential applications in optoelectronic devices.

Contribution

It introduces a novel design of porous SnO2-GO heterojunctions with tunable chemical selectivity and optoelectronic properties for sensing and device applications.

Findings

High UV light responsivity (400A x W-1) with low GO content.

Selective detection of ethanol down to 100 ppb at room temperature.

Tunable chemical selectivity by adjusting GO and SnO2 ratios.

Abstract

The development of high-performing sensing materials, able to detect ppb-trace concentrations of volatile organic compounds at low temperatures, is required for the development of next-generation miniaturized wireless sensors. Here, we present the engineering of selective room-temperature chemical sensors, comprising highly porous tin dioxide (SnO2) - graphene oxide (GO) nano-heterojunction layouts. The optoelectronic and chemical properties of these highly porous (above 90%) p-n heterojunctions were systematically investigated in terms of composition and morphologies. Optimized SnO2-GO layouts demonstrate significant potential as both visible-blind photodetectors and as selective room-temperature chemical sensors. Notably, a low GO content results in an excellent UV light responsivity (400A x W-1), with short rise and decay times, and room-temperature high chemical sensitivity with selective detection of volatile organic compounds such as ethanol down to 100~ppb. In contrast, a high concentration of GO drastically decreases the room-temperature response to ethanol and results in good selectivity to ethylbenzene. The feasibility of tuning the chemical selectivity of the sensor response by engineering the relative amount of GO and SnO2 is a promising feature that may guide the future development of miniaturized solid-state gas sensors. Furthermore, the excellent optoelectronic properties of these SnO2-GO nano-heterojunctions may find applications in various other areas such as optoelectronic devices and (photo)electrocatalysis.