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

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 (SnO 2 )–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 SnO 2 –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 SnO 2 is a promising feature that may guide the future development of miniaturized solid-state gas sensors. Furthermore, the excellent optoelectronic properties of these SnO 2 –GO nanoheterojunctions may find applications in various other areas such as optoelectronic devices and (photo)electrocatalysis.

Carbon-Coated SiO2 Composites as Promising Anode Material for Li-Ion Batteries

“…In contrast, the high-resolution C 1s peak can be fitted with several components, which depend on the preparation conditions. Thus, the components associated with C sp 2 (284.6 eV), sp 3 (285.5 eV), -C-OH (286.5 eV), O-C=O (288.8 eV), and -CO 2 adventitious species (290.7 eV) were identified according with the literature data [ 36 , 37 , 38 ], as depicted in Table 1 . The content in oxygenated carbon is low, in comparison with the C sp 2 and sp 3 which remain the main components (70%), denoting a good graphitization method.…”

Disclosing the Sensitivity and Selectivity of Metal Oxide/Graphene Oxide-Based Chemoresistors towards VOCs

“…Therefore, an improvement of the sensing behavior is justified. Notably, the Sn 0.55 Ti 0.45 O 2 /GO 32:1 solid solution did not show any observable response at room temperature (RT), but the lowest reachable value was 250 • C. All the tested materials were able to sense 100 ppb of acetone even at RT conditions, by exploiting the UV light thanks to the synergistic effect between n-type MOS and p-type GO [4,8]. Indeed, when the device is irradiated by UV light, the photo-excited electron-hole couples can split up.…”

“…Four different n-type semiconductors, namely WO 3 , ZnO, SnO 2 , and Sn 0.55 Ti 0.45 O 2 solid solution, were chosen to be grown onto graphene oxide (GO) material by following a very easy hydrothermal method already reported in our previous works [4][5][6][7][8]. According to earlier studies, we adopted 32:1 salt precursor-to-GO weight ratio, since it resulted in being the optimal one in terms of sensing performances at low operating temperatures.…”

Porous materials applied to biomarker sensing in exhaled breath for monitoring and detecting non-invasive pathologies

“…Selective chemical sensors working at room temperature could also be achieved with highly porous SnO2−graphene oxide nanoheterojunctions layouts. 75 Varying the amount of graphene oxide in the SnO2 nanoparticles network was shown to change the selectivity of the material. For instance, the selectivity was enhanced towards ethanol with low graphene oxide amounts, while the presence of high amounts of graphene oxide hindered the detection of ethanol instead, and raised the selectivity towards ethylbenzene.…”