Progress and future directions in borophene research.

Borophene-an atomically thin, two-dimensional (2D) boron analogue of graphene-has attracted significant attention as a 2D synthetic platform. Since its initial experimental realization, borophene has proven to be a versatile 2D material due to its high polymorphism and amenability to heterostructure integration. Nevertheless, several synthetic challenges have hindered the practical utilization of borophene, primarily due to its high chemical reactivity and interlayer charge transfer with growth substrates. Here we discuss emerging synthesis strategies for borophene, ranging from on-surface synthesis using elemental and molecular boron sources to substrate segregation growth techniques and solution-based reactions. We also focus on the surface and interface engineering of borophene with the aim of tailoring chemical reactivity and electronic properties. Finally, we highlight the remaining unresolved synthetic challenges for borophene and suggest future directions for accelerating fundamental science and applied technology for boron in the 2D limit.