Cooperative Luminescence and Cooperative Sensitisation Upconversion of Lanthanide Complexes in Solution

Abstract

Upconversion materials have led to various breakthrough applications in solar energy conversion, imaging, and biomedicine. One key impediment is the facilitation of such processes at the molecular scale in solution where quenching effects are much more pronounced. In this work, molecular solution‐state cooperative luminescence (CL) upconversion arising from a Yb excited state is explored and the mechanistic origin behind cooperative sensitisation (CS) upconversion in Yb/Tb systems is investigated. Counterintuitively, the best UC performances were obtained for Yb/Tb ratios close to parity, resulting in the brightest molecular upconversion complexes with a quantum yield of 2.8×10−6 at a low laser power density of 2.86 W cm−2.

Distributive Nd-to-Yb Energy Transfer within Pure [YbNdYb] Heterometallic Molecules

“…[20][21] The Ln-to-Ln' ET involved in this sensitization allows for very interesting upor down conversion processes. 22 Up-conversion leads to emission of photons of higher energy than the photons absorbed (anti-Stokes process). 4,[23][24][25] It occurs when the emissive center is capable of accumulating energy from more than one ET event and its advantages make it promising for new applications such as up-conversion lasers, [26][27] improved solar cells 5,28 or bio-probes for theranostics.…”