Iron(III) Complexes with Luminescence Lifetimes of up to 100 ns to Enhance Upconversion and Photocatalysis

Iron is the most
abundant transition metal element and would be
the ideal replacement for noble metals in many applications that rely
on luminescent and long-lived electronically excited states. We show
that efficient reversible energy transfer between doublet excited
states of iron complexes and triplet excited states on organic ligands
improves energy storage by up to 350-fold. As a result, luminescence
lifetimes of up to 100 ns are achieved, the upconversion from red
to blue light becomes 68 times more efficient and the yield of benchmark
photoredox reactions is significantly improved. These advances make
iron coordination compounds more promising candidates for applications
in lighting, solar energy conversion and photocatalysis.