New OLEDs Based on Zirconium Metal-Organic Framework

摘要

The search for new smart-materials in solid-state light-emitting applications,rnlike hybrid organic–inorganic light-emitting devices (OLEDs), has seen anrnintense growth in the recent years. Among all the possibilities, metal-organicrnframeworks (MOFs) have emerged as promising smart materials due to theirrnchemical and structural properties. Herein, for the first time, the use of arnZr-based MOF (Zr-NDC, NDC = dimethyl 2,6-naphthalenedicarboxylate) asrnelectroluminescent active material in OLED devices is reported. The resultsrnindicate that, independently of the properties of the polymer used to form thernemissive layer, the OLED emission is due to radiative electron and hole recombinationrnin the MOF. A tuning of the optoelectronic properties of the device byrnincorporating Coumarin 153, (C153) and 4-(Dicyanomethylene)-2-methyl-6-(4-rndimethylaminostyryl)-4H-pyran, into the MOF pores is demonstrated. Usingrndifferent MOFLED architectures, and MOF composition, it is possible to elucidaternthe photoluminescence and electroluminescence mechanisms, providingrnthe clues for further improvements. It is observed that the current density asrnwell as the electroluminescent behavior depends on the dopant fluorophores.rnIt is also shown that defects within the Zr-MOF play a role in the OLED optoelectronicrnproperties. The results clearly demonstrate the potential of MOFs asrnnew tunable electroluminescent materials for OLED applications.