We report the drastic dependence on pressure of the spectral output of sol-gel derived Yb3+:Y2Si2O7 nanoparticles when excited with the 950 nm emission of a laser diode. The average particle size was estimated 40 nm. The spectrum obtained at atmospheric pressure consisted of an intense blue band. At low pressure the spectrum changed to a wide optical band. (C) 2015 Elsevier B.V. All rights reserved.