Engineering of SnO2-Graphene Oxide Nanoheterojunctions for Selective Room-Temperature Chemical Sensing and Optoelectronic Devices.

Eleonora Pargoletti,Valentina Pifferi,Giuseppe Cappelletti,Umme H Hossain,Thanh Tran-Phu,Gian Luca Chiarello,Iolanda Di Bernardo,Antonio Tricoli,Hongjun Chen,Josh Lipton-Duffin

doi:10.1021/acsami.0c09178

Abstract

The development of high-performing sensing materials, able to detect ppb-trace concentrations of volatile organic compounds (VOCs) at low temperatures, is required for the development of next-generation miniaturized wireless sensors. Here, we present the engineering of selective room-temperature (RT) chemical sensors, comprising highly porous tin dioxide (SnO2)–graphene oxide (GO) nanoheterojunction layouts. The optoelectronic and chemical properties of these highly porous (>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 selective RT chemical sensors. Notably, a low GO content results in an excellent UV light responsivity (400 A W–1), with short rise and decay times, and RT high chemical sensitivity with selective detection of VOCs such as ethanol down to 100 ppb. In contrast, a high concentration of GO drastically decreases the RT response to ethanol and results in good selectivity to ethylbenzene. The feasibility of tuning the chemical selectivity of 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 nanoheterojunctions may find applications in various other areas such as optoelectronic devices and (photo)electrocatalysis.

Highlights

The development of ultraminiaturized and low-power consumption sensors for monitoring of volatile organic compound (VOC) concentrations is becoming increasingly important because of the rapid pace of emission of potentially toxic volatile organic compounds (VOCs) in urban areas and their role as biomarkers in noninvasive medical diagnostics.[1]
The increase of graphene oxide (GO) content hinders ethanol sensing and favors ethylbenzene detection, providing for the first time a mechanism to tailor metal oxide semiconductors (MOS) sensor selectivity. We demonstrated that this optimal nanocomposite structure provides excellent photo- and chemical responses, showcasing their applicability as both visible−blind UV photodetectors and selective RT VOC solidstate sensors
We succeeded in engineering the optoelectronic performance of SnO2−GO nanoheterojunctions for the selective and sensitive measurement of VOCs at RT

Summary

■ INTRODUCTION

The development of ultraminiaturized and low-power consumption sensors for monitoring of volatile organic compound (VOC) concentrations is becoming increasingly important because of the rapid pace of emission of potentially toxic VOCs in urban areas and their role as biomarkers in noninvasive medical diagnostics.[1]. This trend may follow the VOC chemical structure, that is, the presence of polar groups (such as hydroxyl groups) or steric hindrance (as the phenyl ring), leading to different affinities and reactivities with the oxide surface.[57−60] It has been previously reported that alcohols are highly sensed by metal oxides rather than aldehydes or ketones and to a greater extent with respect to nonpolar/low polar analytes, such as ethylbenzene.[59−62] Both SnO2 and 32:1 SnO2−GO readily respond and recover upon purging these three analytes with response and recovery times below 80 s at 350 °C (Figure S4b,c). As a result, tailoring of the GO content in a 3D SnO2 network enables to achieve high sensitivities and selectivities toward different VOCs at RT

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES