Used in solar cells as a semiconductor material due to its favorable band gap and high absorption coefficient. Employed in thin-film photovoltaic devices for efficient light-to-electricity conversion. Applied in nanotechnology for synthesizing copper selenide nanoparticles, which show promise in thermoelectric materials and catalysis. Investigated for use in flexible electronics and optoelectronic devices because of its tunable electrical properties. Also explored in low-cost, large-area photodetectors and sensors.