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 1Wcm−2) and ultrabroad excitation spectrum (Δλ∼80nm).