A charge carrier is a particle that carries an electric charge, allowing electricity to flow through materials. In conductors like metals, the primary charge carriers are electrons, which move freely and enable the conduction of electric current. In semiconductors, both electrons and holes (the absence of an electron) can act as charge carriers, influencing the material's electrical properties. In ionic materials, such as electrolytes, charge carriers are ions that move in response to an electric field. These charge carriers play a crucial role in various applications, including batteries, capacitors, and electronic devices, where efficient charge transport is essential for performance.