Second-order photochemical upconversion in organic systems

J Phys Chem A. 2014 Feb 27;118(8):1439-42. doi: 10.1021/jp5008957. Epub 2014 Feb 11.

Abstract

In order to extend the photon energy shift of sensitized upconversion processes based on triplet-triplet annihilation in multicomponent organic systems, we have demonstrated that it is possible to exploit a sequence of consecutive upconversion steps. We have therefore realized an all-optical device for double upconversion: a light blue-shift of more than 0.9 eV was obtained at an excitation irradiance of a few tens of milliwatts per square centimeter.