Ceramics arising from Pb(Mg_1/3Nb_2/3)_1‑x TixO₃ with composition near the morphotropic phase boundary (MPB) were prepared by the modified solid-state reaction method. The synthesized ceramics were characterized, and then the operating principles of pyroelectric and piezoelectric harvesters are reviewed. In addition, the dielectric behavior is measured to determine the dielectric constant and losses at different temperatures and frequencies. The typical behavior of a ferroelectric relaxer was observed by adding the PbTiO₃ phase. The thermal properties are also analyzed by PPE calorimetry, presaging a one-dimensional heat-flow process. As a result, the dielectric and thermal behaviors of the as-prepared ceramics as well as their thermal stability are intimately linked to the PbTiO₃ addition to PbMg_l/3Nb_2/3O₃ phase. These materials exhibit good physical performances, which makes them promising candidates for pyroelectric micro-generators (PEG), cooling systems and infrared applications.

We deal with the thermal energy which is one of the ambient energy sources surely exploitable, but it has not been much interest as the mechanical energy. In the last decades, direct energy conversion devices received particular attention because of the need to develop flexible systems, autonomous and self-powered. The energy harvesting aims to make the systems, autonomous in terms of energy and to contribute to sustainable development by the total respect of the environment. In this paper, our aim is to use thermal energy and show that it's an important source for producing the electrical energy through pyroelectric effect: first, elaborate charged polyurethane (PU) with different proportions (20%, 30% and 40%) of lead zirconate titanate (PZT), then to use those PZT/PU composites as a pyroelectric energy harvesting systems. Secondly, the optimization of energy harvesting and storage. The PZT/PU composite prepared is considered as one of the most promising composites for energy harvesting systems, due its various advantages, such as mechanical flexibility, high temperature sensitivity, low cost as well as its high electro-active functional properties. The current generated by all samples for temperature fluctuations over a period of time in the order of 140 s have been rectified and stored in a charge capacitor of 1μF. The stored energy can reach a maximum value in the order of 14μW for a composite loaded with 40% PZT. Therefore, these composites show an interesting potential to be used in various applications. These results shed light on the thermoelectric energy conversion by a new composite of PZT/PU having the pyroelectric property.

Harvesting energy using intelligent piezoelectric and pyroelectric materials allows autonomy in terms of energy and contributes to sustainable development by the total respect of the environment. Furthermore, energy harvesting is currently a topic of intense interest as a result of the growing energy demands of society and as a technology to create autonomous and self-powered sensors. In this work, we present an analytical model of the sensor input (Thermal energy) and its output (Electrical energy), using the pyroelectric material (PZT). This model depends on the applied heat flow and the thermal and electrical properties of the PZT. A 2D finite element modeling (FEM) using numerical calculation software has been studied to simulate the temperature field within the thermal sensor. Indeed, this numerical modeling has been used to confirm the validity of our theoretical model. Consequently, both the numerical and theoretical sensor model gave the same output result, which was around 0.58 μW/m² for a heat flow input of 2000 W/m².

There is a large amount of thermal energy wasted during the driving cycle of all kinds of vehicles. In this paper, a pyroelectric harvester system, based on temperature change, is designed for low-powered sensors for the reliable electronic/electric architecture development of autonomous vehicles. In fact, this harvester was designed, specifically, in order to capture the temperature of the braking system and convert the wasted heat energy during the contact process to electrical energy. This conversion process occurs due to the temperature variation through the pyroelectric material, given the cooling phenomena of the ambient air. The energy potentially available in the form of heat produced by the friction involved in braking was evaluated using finite element analysis in the multiphysics software environment. Therefore, we present simulations of disc heating and cooling during the braking process at different speeds. Moreover, the potential for energy harvesting in multiple rolling conditions is discussed, such as the braking cycles and the effect of the material thickness used in the conversion module. The proposed system has undergone simulation analysis, which shows that the system can generate a voltage of 10.8 V and a power of 7.0 mW for a cycle of one braking process and around 9.5 mW for a cycle containing two successive braking's. The results of the simulation study verify the feasibility of the system and demonstrate its pertinence, especially for low-power sensors for new vehicle generations.

In this study, we employ impedance spectroscopy to investigate the internal mechanisms influencing the efficiency and performance of perovskite solar cells (PSCs). Using SCAPS-1D software (version 3.3.10), we simulate the FTO/ZnO/MASnI₃/NiOx/Au heterostructure to analyze the complex impedance (Z*) and electric modulus (M*). This approach allows us to differentiate between bulk material properties and interface phenomena, such as ion migration, charge transport, and recombination dynamics. Through Nyquist and Bode plots, we identify three distinct relaxation processes associated with charge migration, interface polarization, and charge injection/extraction at the electrodes. To achieve a more comprehensive understanding, we model the impedance and modulus spectra using an equivalent electrical circuit, which accurately reproduces the experimental data. Our analysis reveals that increasing the bias voltage extends the relaxation times for charge transport and interface polarization, highlighting a decline in performance under higher operational voltages. This performance drop is attributed to elevated resistive losses and enhanced recombination processes, which become more pronounced at higher fields. These findings emphasize the importance of optimizing both bulk material properties and interface engineering to mitigate losses and improve the overall performance and stability of PSCs.