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

Efficient and long‐range exciton transport is critical for photosynthesis and opto‐electronic devices, and for triplet‐harvesting materials, triplet exciton diffusion length (LD ) and coefficient (D ) 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. Exciton transport plays a pivotal role in organic opto‐electronics. Effective triplet energy transfer is difficult to achieve, due to the less efficient Dexter mechanism for triplet exciton transport than Förster resonant energy transfer for singlet exciton transport. Herein, we show that organic PtII and PdII nanowires exhibit long‐range triplet exciton diffusion lengths with large diffusion coefficients by metal–metal interaction at room temperature.