Bandgap-Tunable Preparation of Smooth and Large Two-Dimensional Antimonene

As a highly stable band gap semiconductor, antimonene is an intriguing two-dimensional (2D) material in optoelectronics. However, its short layer distance and strong binding energy make it challenging to prepare high-quality large 2D antimonene; therefore, its predicted tunable band gap has not been experimentally confirmed. Now, an approach to prepare smooth and large 2D antimonene with uniform layers that uses a pregrinding and subsequent sonication-assisted liquid-phase exfoliation process has been established. Mortar pregrinding provides a shear force along the layer surfaces, forming large, thin antimony plates, which can then easily be exfoliated into smooth, large antimonene, avoiding long sonication times and antimonene destruction. The resulting antimonene also enabled verification of the tunable band gap from 0.8 eV to 1.44 eV. Hole extraction and current enhancement by about 30 % occurred when the antimonene was used as a hole transport layer in perovskite solar cells.