High-Efficiency Electrogenerated Chemiluminescence of Novel Zr-Based Metal-Organic Frameworks through Organic Linkers Regulation

Exploiting efficiently luminescent metal-organic frameworks (MOFs) for electrogenerated chemiluminescence (ECL) in aqueous solution is very intriguing and challenging. Described here are novel Zr-based metal-organic frameworks (MOFs) electrochemiluminophores (ECLphores) synthesized through a facile solvothermal method by using polycyclic aromatic hydrocarbons (PAHs) as organic linkers. The photoluminescence (PL) and ECL of Zr-based MOFs are affected by the actual organic linkers' inherent properties and activities. The tetraphenyl-carboxylate-pyrene derived NU-1000 shows the best ECL performance and reveals an enormous ECL quantum efficiency of 1.42-fold higher than that of the standard Ru(bpy)(3)(2+) by using K2S2O8 as the coreactant. Due to its providential energy gap, it facilitated the feasibility of electron removal and injection identified by experiments and density functional theory (DFT) calculations. Moreover, the ECL mechanisms of NU-1000 were elucidated based on the voltammetric ECL method, photoluminescence, and spooling ECL spectroscopies. The exceptional porosity and high surface area for the acceleration of mass and electron transfer during electrochemical reactions, along with the coordination immobilization of ECL active PAHs onto the MOF nodes for abolishing energy loss caused by notorious pi-pi stacking and intramolecular rotation, representing significant advantages in the development of Zr-based MOFs for ECL applications.