Nickelocene-Precursor-Facilitated Fast Growth of Graphene/h-BN Vertical Heterostructures and Its Applications in OLEDs

The direct growth of high-quality, large-area, uniform, vertically stacked Gr/h-BN heterostructures is of vital importance for applications in electronics and optoelectronics. However, the main challenge lies in the catalytically inert nature of the hexagonal boron nitride (h-BN) substrates, which usually afford a rather low decomposition rate of carbon precursors, and thus relatively low growth rate of graphene. Herein, a nickelocene-precursor-facilitated route is developed for the fast growth of Gr/h-BN vertical heterostructures on Cu foils, which shows much improved synthesis efficiency (8–10 times faster) and crystalline quality of graphene (large single-crystalline domain up to ≈20 µm). The key advantage of our synthetic route is the utilization of nickel atoms that are decomposed from nickelocene molecules as the gaseous catalyst, which can decrease the energy barrier for graphene growth and facilitate the decomposition of carbon sources, according to our density functional theory calculations. The high-quality Gr/h-BN stacks are proved to be perfect anode/protecting layers for high-performance organic light-emitting diode devices. In this regard, this work offers a brand-new route for the fast growth of Gr/h-BN heterostructures with practical scalability and high crystalline quality, thus should propel its wide applications in transparent electrodes, high-performance electronic devices, and energy harvesting/transition directions.

Vertically stacked graphene/hexagonal boron nitride (Gr/h-BN) heterostructures are fabricated by a metal-atom-facilitated sequential chemical vapor deposition route with nickelocene as the graphene precursor. The nickelocene-precursor-based synthetic route shows much improved growth efficiency as compared to that of the previous benzoic-acid-based route. The as-grown, high-quality Gr/h-BN stacks are utilized as perfect anode/protecting layers for high-performance organic light-emitting diode devices.

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