Upconversion with ultrabroad excitation band: Simultaneous use of two sensitizers

The authors demonstrate the ability to combine sensitizers effectively working with single emitter in order to increase the excitation window for noncoherent upconversion. They show effective upconversion of the red part of the sun spectrum realized by ultralow excitation intensity (as low as 1 W cm(-2)) and ultrabroad excitation spectrum (Delta lambda similar to 80 nm). (c) 2007 American Institute of Physics.