Single-layer light emitting diodes (LEDs) were fabricated using poly[bis(p-butylphenyl)silane] as the emissive layer. An efficient and stable electroluminescence with a maximum at 407 nm was observed at room temperature under a forward electric field greater than6×105 V/cm.The coincidence of electroluminescence with photoluminescence suggests the origin of the electroluminescence in an excited silicon chain segment. The high external quantum efficiency (0.1&percent; photons/electron), narrow emission (full width at halfmaximum=15 nm), improved operating stability, and good solubility in organic solvents provide the possibility of using polysilanes for ultraviolet LEDs. ©1997 American Institute of Physics.