Fullerene and fullerene-aluminum nanostructured films as sensitive layers for gas sensors

Abstract

The responses of quartz crystal microbalance (QCM) sensors coated by fullerene and fullerene-aluminum films to ethanol and water vapors are investigated. The possibility of controlling the adsorption properties of such films by inserting the aluminum and by ultraviolet irradiation that changes the film morphology in a definite way is demonstrated.

Nanoporous Organic Field‐Effect Transistors Employing a Calixarene Dielectric for Sub‐ppb Gas Sensing

“…[2][3][4] Organic field-effect transistors (OFET) can be used to monitor these modifications for gas sensing applications. [2,5,6] OFET-based gas sensors can be classified into direct sensors, where the modulation of the electric signal arises from the modification of the semiconductor itself, e.g., by the insertion of host molecules in the grain boundaries between OSC crystals, [5,7] or indirect sensors, where the modulation of the electric signal comes from the device configuration, e.g., by the addition of a sensing layer between the dielectric and the OSC. [2,8] Because charge transport and sensing occur mainly in the first few layers of molecules near the dielectric, [9] the sensitivity of the sensor is often limited by the diffusion of the analyte to this region.…”

“…[7,14] These templates require cross-linking prior to pattern transfer to the OSC using chlorinated solvents, [7] making their specific chemical functionalization toward gas sensing challenging. In the approach that we follow here, nanoporous films of 6,13-bis(triisopropylsilyle thynyl)pentacene (TIPS-Pn) were interfacially self-assembled on a water-air interface, [15,16] allowing facile deposition on a sensitive 4-tert-butylcalix [6]arene gate dielectric. Calixarenes are cyclic molecules allowing specific supramolecular interactions through molecular engineering of the functional moieties decorating the rims of the chalice.…”

“…Nanoporous films of OSCs are, however, challenging to produce and to transfer into working sensors. Usage of nanoporous OSC films deposited on a sensitive 4-tert-butylcalix [6]arene gate dielectric as the active layer of an OFET-based gas sensor is proposed here. The semiconducting molecules are self-assembled into nanoporous films at the interface between air and water, allowing their transfer to practically any gassensitive dielectric substrate.…”

“…The sensing dielectric layer used in this study, 4-tert-butylcalix [6]arene was spin-coated from chloroform, [24] to reach homogeneous films with a thickness of 50 ± 2 nm. The characteristics of transistors fabricated on this dielectric were comparable to those observed on pure Si/SiO 2 .…”

“…It was found that charge injection in the nanoporous film and device reproducibility was improved by using a top-contact configuration. The characteristics of a bottom gate, top contact transistor based on a 4-tert-butylcalix [6]arene dielectric layer are shown in Figure 1d (transfer curves) and Figure 1e (output curves). The leakage current and the square root of I D as a function of V G are shown in Figure S5 in the Supporting Information.…”