Tobacco Use by Urbanization Level Among U.S. Adults, 2024.

Transition metal chalcogenides generally offer a wide range of applications. Concretely, copper() silver selenide, CuAgSe, has potential for use in photocatalysis, in biomedicine due to its antibacterial activity, and in thermoelectrics, either as a traditional solid-state thermoelectric material or flexible thermoelectric devices (F-TED). The latter has the potential to be used in wearable devices as a self-powered and maintenance-free power supply for flexible electronics. The appeal of CuAgSe compounds is attributable not only to their excellent thermoelectric properties but also to their unusual mechanical properties – specifically, flexibility and ductility – which are essential for their use in F-TEDs. These properties can be effectively tailored by introducing suitable secondary phases in the matrix component. The employment of ball milling technology in the fabrication of F-TEDs appears to be a promising avenue for research, as it enables a one-pot ball-milling method for the simultaneous and efficient preparation/synthesis of active thermoelectric materials/composites, which can subsequently be utilised in ink formulations for direct application in screen printing or 3D printing processes in the F-TED production line. In principle, thermoelectric materials are capable of direct conversion of thermal energy into electrical energy and reversibly convert electrical energy into heat. The thermoelectric figure of merit , which allows comparison of various thermoelectric materials, can be calculated according to :where is electrical conductivity, is Seebeck coefficient, is thermal conductivity, and is temperature in K. An overview of reported CuAgSe values is provided in the Discussion section below. CuAgSe, a synthetic analogue of natural mineral eucairite, undergoes a reversible phase transition in the temperature range 463–468 K, connected with a crystal structure change from tetragonal or orthorhombic low-temperature β-CuAgSe to cubic high-temperature α-CuAgSe with superionic behaviour. An interesting fact is that CuSe is a p-type semiconductor, AgSe is n-type, while CuAgSe exhibits switching between these two types during phase transition.