Silicon Nanocrystals with Ensemble Quantum Yields Exceeding 60% (Proto-IRG).Silicon is widely used for microelectronics due to its excellent electrical properties. Unfortunately, its optical properties are poor, which has so far prevented its application as light-emitting material. The photophysical properties of small silicon crystals improve drastically when reduced in size to a few nanometers. The proto-IRG has developed a plasma gas discharge approach to produce macroscopic amounts of high quality silicon nanocrystals. Through proper functionalization of the nanocrystal surfaces by binding organic molecules to silicon surface atoms, the group achieved a so far unprecedented optical activity of silicon. Efficient visible light emission from silicon nanocrystals was observed upon irradiation with ultraviolet (UV) light. Quantum yields, defined as visible photons emitted per UV photons absorbed, of 67% were observed, bettering previous reports of ~30%. This development may make silicon a suitable material for light-emitting devices in optical communications, display devices, and new applications in bio-imaging. [Jurbergs, D.*; Mangolini, L.; Rogojina, E.*; Kortshagen, U. Silicon Nanocrystals with Ensemble Quantum Yields Exceeding 60%. Appl. Phys. Lett. 88 233116, 2006