Layer-by-Layer Films with CoFe2O4Nanocrystals and Graphene Oxide as a Sensitive Interface in Capacitive Field-Effect Devices
Year: 2022
Type: article
Abstract: Sensor devices have proved to be a promising technology for portable microelectronic systems for biomedical and environmental applications. Depending on the target analyte and/or the sensor platform chosen, the study of (nano)materials and their ideal incorporation in the device as a receptor layer have great importance for developing sensing units with enhanced properties and performance. Here, we employed the layer-by-layer (LbL) technique to fabricate nanostructured films as sensing units for detecting H 2 O 2 and heavy metal ions (Cd 2+ and Cu 2+ ). The LbL film was deposited on electrolyte–insulator–semiconductor (EIS) field-effect devices, combining CoFe 2 O 4 nanocrystals embedded into polyallylamine hydrochloride (PAH) and graphene oxide (GO) as a PAH-CoFe 2 O 4 /GO structure. Scanning electron microscopy revealed a LbL film morphology with high surface area presenting heterogeneous clusters of nanocrystals covered by a homogeneous coating of GO. The electrochemical characterization to monitor the film growth and the sensing properties for detecting H 2 O 2 and Cd 2+ and Cu 2+ ions was carried out by capacitance–voltage ( C / V ) and constant-capacitance (ConCap) measurements. The results demonstrated catalytic features in detection experiments for an optimized EIS-LbL sensor containing a 6-bilayer PAH-CoFe 2 O 4 /GO LbL film. This sensor system was sensitive for all analytes and exhibited a low limit of detection of ca. 314.3 μM for H 2 O 2 and 0.54 and 0.47 μM for Cd 2+ and Cu 2+ ions, respectively. These findings prove the relevance of incorporating nanostructured films as a receptor layer to enhance sensing properties and may envisage a proof-of-concept field-effect sensor system for environmental applications.
Source: ACS Applied Nano Materials
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4220848675