The electrocaloric effect was investigated in lead-free Zr doped Ba_0.8Ca_0.2(Zr_xTi_1−x)O₃ (BCTZ) ceramics synthesized by a conventional sintering process. Room-temperature x-ray diffraction analysis showed that the tetragonal structure is obtained in BCTZ for x $\le$ 0.08 and a pseudo cubic phase for x > 0.08. The dielectric spectroscopy and calorimetry revealed that the Curie temperature decreases as a consequence of Zr doping and that the BCTZ exhibits a first order ferroelectric phase transition. The electrocaloric effect was determined by the calculation of the electrocaloric change of temperature (ΔT) using the Maxwell relation based on the P–E hysteresis loops measured at different temperatures. A large electrocaloric responsivity ΔT/ΔE = 0.34 × 10⁻⁶Km/V was found for x = 0.04, which significantly exceeds of values found so far in other lead-free electrocaloric materials.

In the surge of recent successes of 2D materials following the rise of graphene, molybdenum disulfide (2D-MoS₂) has been attracting growing attention from both fundamental and applications viewpoints, owing to the combination of its unique nanoscale properties. For instance, the bandgap of 2D-MoS₂, which changes from direct (in the bulk form) to indirect for ultrathin films (few layers), offers new prospects for various applications in optoelectronics. In this review, we present the latest scientific advances in the field of synthesis and characterization of 2D-MoS₂ films while highlighting some of their applications in energy harvesting, gas sensing, and plasmonic devices. A survey of the physical and chemical processing routes of 2D-MoS₂ is presented first, followed by a detailed description and listing of the most relevant characterization techniques used to study the MoS₂ nanomaterial as well as theoretical simulations of its interesting optical properties. Finally, the challenges related to the synthesis of high quality and fairly controllable MoS₂ thin films are discussed along with their integration into novel functional devices.

Polycrystalline lead-free Sodium Bismuth Titanate (NBT) ferroelectric ceramics doped with rare earth (RE) element are prepared using solid state reaction method. Optical, ferroelectric, and electrocaloric properties were investigated. The introduction of RE³⁺ ions in the NBT host lattice shows different light emissions over the wavelength range from visible to near infrared region. The ferroelectric P-E hysteresis loops exhibit an antiferroelectric-like character near room temperature indicating possible existence of a morphotropic phase boundary. The enhanced electrocaloric response was observed in a broad temperature range due to nearly merged phase transitions. Coexistence of optical and electrocaloric properties is very promising for photonics or optoelectronic device applications.