Organic-inorganic perovskites have revolutionized the optoelectronics field, providing materials with a wide range of properties for solving numerous applications. Indeed, much recent work has been focused on nanostructured perovskites, with quantum dots, nanowires, and nanoplatelets showing tremendous potential. Here, we utilize the unique tunability of 2D perovskite nanoplatelets to build LEDs that span the visible spectrum. Quantum confinement in the z direction drives a significant blueshift, allowing for blue devices utilizing the bromide system and orange devices utilizing the iodide system. We demonstrate that excess ligand addition is crucial to achieving this blueshift in thin films that otherwise suffer from energy funneling. We build devices that show electroluminescence from 440 nm to 650 nm, although they still suffer from low efficiencies due to low photoluminescence quantum yields. We finally demonstrate that these materials suffer from reversible degradation with an applied electric field, further limiting the efficiency. The favorable optoelectronic properties of perovskite materials, combined with the blueshift due to quantum confinement, shows the promise of these materials as a new class of low cost emitters.
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