Rare earth activated nanophosphors have attracted extensive attention because of their potential applications in lighting

display and fluorescence bio-label

and also of their elementary importance on under-standing of the 4f

N

electronic transition properties of rare earth ions in nanosized particles.In the latest ten years

a great number of improvements have been achieved in this field.In this review article

we mainly present some important research results on photo luminescence properties of rare earth doped oxide nanophos-phors.The contents concern exciton and charge transfer transitions

symmetry sites and local environmentssurrounding rare earth ions

radiative transition and nonradiative relaxation processses on 4f

N

states

tempra-ture-quenching and concentration-quenching of luminescence

energy transferamong rare earths

electron-pho-non coupling

ultravoilet irradiation induced spectral change andetc.Besides

the luminescence properties ofrare earth actived one-dimensional oxide nanowires(tubes

rods)and upconversion nanophosphors were intro-duced independently.It is expected thatmore universal conclusions relative to nanoparticle size and structureon the photolum inescence of rare earth actived nanoparticles can be drawn

however

it should be noted that some results introduced here might be still controversal

because some photolum inescence properties depend strongly on the preparation technique and detailed conditions.