Sensitizing phosphorescent and radical emitters via triplet energy translation from CsPbBr3 nanocrystals

Abstract

Colloidal semiconductor nanocrystals can effectively sensitize surface-attached molecular species via triplet energy transfer. These sensitized molecular triplets are capable of triggering a variety of subsequent processes such as triplet-fusion upconversion, singlet oxygen generation and organic synthesis. Here we demonstrate that molecular triplets can also sensitize non-conventional light-emitting materials such as phosphorescent and radical molecules. Specifically, photoexcitation of CsPbBr₃ perovskite nanocrystals resulted in triplet sensitization of naphthalene ligands, which further translated the energy into 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum(II) or (4-(4′-triphenylamine-yl)-tetrachlorophenyl)bis-(pentachlorophenyl)-methyl in the bulk solution that can efficiently emit photons. As a result, the light absorption of phosphorescent and radical molecules is strongly enhanced and photon emission is effectively down-shifted from absorption. This new energy transduction scheme may prove useful in devices such as luminescent solar concentrators.