Efficient Long‐Range Triplet Exciton Transport by Metal–Metal Interaction at Room Temperature

Abstract

Efficient and long-range exciton transport is critical for photosynthesis and opto-electronic devices, and for triplet-harvesting materials, triplet exciton diffusion length ((Formula presented.)) and coefficient ((Formula presented.)) are key parameters in determining their performances. Herein, we observed that PtII and PdII organometallic nanowires exhibit long-range anisotropic triplet exciton LD of 5–7 μm along the M−M direction using direct photoluminescence (PL) imaging technique by low-power continuous wave (CW) laser excitation. At room temperature, via a combined triplet–triplet annihilation (TTA) analysis and spatial PL imaging, an efficient triplet exciton diffusion was observed for the PtII and PdII nanowires with extended close M−M contact, while is absent in nanowires without close M−M contact. Two-dimensional electronic spectroscopy (2DES) and calculations revealed a significant contribution of the delocalized 1/3[dσ*(M−M)→π*] excited state during the exciton diffusion modulated by the M−M distance.