Nickel selenide is widely used in electronic and optoelectronic devices due to its semiconductor properties. It serves as a key material in solar cells, where it functions as a light-absorbing layer or as a buffer layer to improve charge transport. Its high absorption coefficient allows efficient conversion of sunlight into electricity, making it suitable for thin-film photovoltaic technologies.

In addition, nickel selenide is employed in thermoelectric devices that convert heat into electrical energy, benefiting from its good electrical conductivity and low thermal conductivity. It is also used as a catalyst in hydrogen evolution reactions for water splitting, offering a cost-effective alternative to precious metal catalysts in renewable energy systems.

Due to its stability and electrochemical properties, it finds application in rechargeable batteries and supercapacitors, enhancing electrode performance and energy storage capacity. Nickel selenide nanoparticles are explored in sensors and nanoelectronics, where their size-dependent properties enable high sensitivity and miniaturization.