Interfacing Lanthanide Metal-Organic Frameworks with ZnO Nanowires for Alternating Current Electroluminescence

Alternating current electroluminescence (ACEL) devices are attractive candidates in cost-effective lighting, sensing, and flexible displays due to their uniform luminescence, stable performance, and outstanding deformability. However, ACEL devices have suffered from limited options for the light-emitting layer, which presents a significant constraint in the progress of utilizing ACEL. Herein, a new class of ACEL phosphors based on lanthanide metal-organic frameworks (Ln-MOFs) is devised. A synthesis of lanthanide-benzenetricarboxylate (Ln-BTC) thin film on a brass grid substrate seeded with ZnO nanowires (NWs) as anchors is developed. The as-synthesized Ln-BTC thin film is employed as the emissive layer and shows visible electroluminescence driven by alternating current (2.9 V & mu;m-1, 1 kHz) for the first time. Mechanistic investigations reveal that the Ln-based ACEL stems from impact excitation by accelerated electrons from ZnO NWs. Fine-tuning of the ACEL color is also demonstrated by controlling the Ln-MOF compositions and introducing an extra ZnS emitting layer. The advances in these optical materials expand the application of ACEL devices in anti-counterfeiting. Lanthanide-benzenetricarboxylate (Ln-BTC) thin film is constructed by growing Tb/Eu-BTC multipod arrays on brass grid substrate seeded with ZnO nanowires as anchors and employed as alternating current electroluminescence (ACEL) emissive layer. ACEL color can be tuned across the blue and red regions in the spectrum by controlling the lanthanide composition and introducing an extra ZnS emitting layer.image