Circularly Polarized Absorption and Luminescence of Semiconductor Eu-OCN Nanocrystals in the Blue Region of the Electromagnetic Spectrum.

Semiconductor nanomaterials with efficient polarized-light control in the blue region of the visible spectrum are promising candidates for modern and future photo-information technology, display devices, and optical sensing applications. New-type semiconductor Eu(OCN) nanocrystals with circularly polarized absorption (CD: circular dichroism) and emission (CPL: circularly polarized luminescence) under an applied magnetic field are demonstrated here for the first time. The effective CD signal at 1.6 T was observed at approximately 440 nm. The dissymmetry factor of CPL under 100 K, g was estimated to be 0.01. These characteristic circularly polarized absorption and emission phenomena of Eu(OCN) nanocrystals should be caused by combination between the "Faraday A and C terms" of the magnetic moment in the excited state. Polarized-light control using Eu(OCN) nanocrystals in the blue-light region of the electromagnetic spectrum is a large first step into a new world of photo-functional semiconductor nanomaterials.