Ligand Engineering Enhances Electrical Conductivity in Photoluminescent Coordination Polymers.

Abstract

Metal-organic frameworks (MOFs) or coordination polymers (CPs) typically exhibit poor electrical conductivity due to rapid electron-hole recombination, which hampers their promising prospects in energy storage and conversion. Hence, the precise regulation of charge transport properties in a controllable manner remains a critical challenge. Herein, we report a ligand engineering strategy to enhance the electrical conductivity of photoluminescent CPs using pyridyl-modified triazolyl ligands and Cu(I) metal centers. By modulating the substituent and isomerism of the ligand, distinct structural topologies with varied π-π stacking sequences were successfully achieved. Notably, systematic investigations of the structure-property relationship demonstrate that, as the π-π stacking interaction increases, the photoluminescence quantum yield (PLQY) decreases from 19.36 to 7.89%, while the electrical conductivity of CPs increases remarkably from 9.04 × 10-7 to 1.11 × 10-5 S cm-1 at room temperature. These findings reveal the critical role of π-π stacking in governing the conductive performance of photoluminescent CPs. Collectively, this work exemplifies a molecular engineering strategy for tailoring charge transport properties through precise supramolecular interactions.