To realize low-cost, environmentally friendly electronic devices and circuits, there is currently a strong trend to explore plant-based dielectric materials because they can be responsibly sourced from agricultural or forest vegetation, are generally water-soluble, and possess good electrical insulator properties. In this contribution, organic field-effect transistors (OFETs) using a biopolymer dielectric obtained from exudates of Anacardium occidentale Linn. trees, namely, cashew gum (CG), are reported. To characterise the physical and dielectric properties of the gum, thin films and metal-insulator-metal (MIM) capacitors were prepared and characterized. To evaluate the material’s performance in OFETs, bottom-gate top-contact (BGTC) p-channel poly [3,6-di(2-thien-5-yl)-2,5-di(2-octyldodecyl)-pyrrolo (3,4-c)pyrrole-1,4-dione) thieno (3,2-b) thiophene]:polymethyl methacrylate (DPPTTT:PMMA) transistors were engineered and studied. The fabricated MIM capacitors display a comparatively high areal capacitance of 260 nF/cm² at 1 kHz for 130 nm thick films. As a result, the solution-processed DPPTTT:PMMA OFETs favourably operate at 3 V with the average saturation field-effect mobility equal to 0.20 cm²/Vs., threshold voltage around −1.4 V, subthreshold swing in the region of 250 mV/dec, and ON/OFF current ratio well above 10³. As such, cashew gum emerges as a promising dielectric for sustainable manufacturing of solution-processed organic FETs.

In this article, we present a new model for glucose detection using an electrochemical field-effect transistor (ElecFET) with the MATLAB software. ElecFET is a device in which the basic element is a pH-sensitive chemical field-effect transistor (pH-ChemFET) designed with an integrated platinum microelectrode around the sensitive gate dielectric capable to trigger electrochemical reactions. A number of parameters, such as polarization time (Tpol) and polarization voltage (Vp), have been investigated, as well as the enzymatic unit number per volume (Nenz), the Michaelis constant (KM), and the glucose concentration (C₀). Each of the aforementioned parameters influences the glucose sensor response. Experimental data compared with our numerical model showed a reasonable fit.

The omnipresence of connected objects leads to the quasi-permanent presence of electromagnetic waves from different sources in our environment. This article presents a new electromagnetic energy harvesting device, rectenna type, which offers the advantage of being versatile. Indeed, the proposed prototype is compatible with three frequency bands of radio standards widely deployed today (UHF RFID, GSM-1800, and UMTS-2100), and its performances remain good for low to very low ambient power levels as well as for different loads depending on the targeted application. The proposed solution is based on a tri-band antenna with very good efficiency and a bandwidth of at least 80 MHz for each of the operating frequencies. Moreover, the associated rectifier circuit is also tri-band and offers good performance in terms of RF-to-DC conversion efficiency for input levels varying in a rather wide range of power levels. The study is based on a design phase by simulation until the realization of prototypes and their experimental characterization. The designed rectenna is compared with solutions found in the literature.