Self-powered sensors are gaining a lot of attention in recent years due to their possible application in the Internet of Things, medical implants and wireless and wearable devices. Human breath detection has applications in diagnostics, medical therapy and metabolism monitoring. One possible approach for breath monitoring is detecting the humidity in exhaled air. Here, we present an extremely sensitive, self-powered sensor for breath humidity monitoring. As a power source, the sensor uses electromagnetic energy harvested from the environment. Even electromagnetic energy harvested from the human body is enough for the operation of this sensor. The signal obtained using the human body as a source was up to 100 mV with an estimated power of 1 nW. The relatively low amount of energy that could be harvested in this way was producing a signal that was modulated by an interdigitated capacitor made out of electrochemically activated aluminum. The signal obtained in this way was rectified by a set of Schottky diodes and measured by a voltmeter. The sensor was capable of following a variety of different respiration patterns during normal breathing, exercise and rest, at the same time powered only by electromagnetic energy harvested from the human body. Everything happened in the normal environment used for everyday work and life, without any additional sources, and at a safe level of electromagnetic radiation.

The key equipment for performing aerodynamic testing of objects, such as road and railway vehicles, aircraft, and wind turbines, as well as stationary objects such as bridges and buildings, are multichannel pressure measurement instruments (pressure scanners). These instruments are typically based on arrays of separate pressure sensors built in an enclosure that also contains temperature sensors used for temperature compensation. However, there are significant limitations to such a construction, especially when increasing requirements in terms of miniaturization, the number of pressure channels, and high measurement performance must be met at the same time. In this paper, we present the development and realization of an innovative MEMS multisensor chip, which is designed with the intention of overcoming these limitations. The chip has four MEMS piezoresistive pressure-sensing elements and two resistive temperature-sensing elements, which are all monolithically integrated, enabling better sensor matching and thermal coupling while providing a high number of pressure channels per unit area. The main steps of chip development are preliminary chip design, numerical simulations of the chip’s mechanical behavior when exposed to the measured pressure, final chip design, fabrication processes (photolithography, thermal oxidation, diffusion, layer deposition, micromachining, anodic bonding, and wafer dicing), and electrical testing.

The existing instruments for aerodynamic pressure measurements are usually built around an array of discrete pressure sensors, placed in the same housing together with a few discrete temperature sensors. However, this approach is limiting, especially regarding miniaturization, sensor matching, and thermal coupling. In this work, we intend to overcome these limitations by proposing a novel MEMS multisensor chip, which has a monolithically integrated matrix of four piezoresistive MEMS pressure-sensing elements and two resistive temperature-sensing elements. After finishing the preliminary chip design, we performed computer simulations in order to assess its mechanical behavior when measured pressure is applied. Subsequently, the final chip design was completed, and the first batch was fabricated. The used technological processes included photolithography, thermal oxidation, diffusion, sputtering, micromachining (wet chemical etching), anodic bonding, and wafer dicing.

The blocking layer is crucial for inhibiting recombination processes in photovoltaics that utilize oxide semiconductors, such as dye-sensitized solar cells (DSSCs), quantum-dot-sensitized solar cells (QDSSCs), and perovskite solar cells. However, its effectiveness strongly depends on the chosen deposition method. This study systematically evaluates the most suitable approach for obtaining a uniform, pinhole-free titanium dioxide (TiO₂) blocking layer by using three deposition methods: radio-frequency sputtering, spin-coating, and chemical bath deposition. The electrochemical, optical, and morphological properties of blocking layers were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), UV-VIS spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM). KPFM analysis, together with CV and EIS, revealed that the lower R_ct values and higher CV currents observed in spin-coated (SC_11-33) and vertically deposited CBD films (CB_5, CB_6) resulted from incomplete FTO coverage. In contrast, sputtered (SP_21-24) and horizontally deposited CBD films (CB_1, CB_2) demonstrated significantly higher R_ct values and improved surface coverage. Full DSSCs fabricated with SP_23, SC_33, and CB_2 confirmed the correlation between interfacial properties and photovoltaic performance. This combined approach offers a fast, material-efficient, and environmentally conscious screening method for optimizing blocking layers in solar cell technologies.

Respiratory function monitoring is essential for the early detection of respiratory dysfunction and for managing critical care patients. Various techniques have been developed for the monitoring of respiratory function, including non-invasive methods such as breath humidity detection. In this work, we show preliminary results of fabrication and testing of self-powered, flexible and wearable breath humidity detection sensor. The Electrochemical Impedance Spectroscopy was deployed to quantify properties of the screen-printed humidity sensor with possible use in human respiration monitoring.

This report explains the process of fabricating a flexible chemical sensor on a Polyethylene terephthalate (PET) substrate by using screen-printing technology. The sensor was tested for its response to body fluid (saliva) using Electrochemical Impedance Spectroscopy (EIS). The experiments show that the sensor is capable of differentiating between water and saliva, and it can be used for identifying body fluids., i.e., distinguishing between saliva or water, and detecting personal biomarkers present in the physiology.