2D Cairo Pentagonal PdPS: Air‐Stable Anisotropic Ternary Semiconductor with High Optoelectronic Performance

Abstract Pentagonal 2D materials as a new member in the 2D material family have attracted increasing attention due to the exotic physical properties originating from the unique Cairo pentagonal tiling topology. Herein, the penta‐PdPS atomic layers as a new air‐stable 2D semiconductor with the unique puckered pentagonal low‐symmetry structure are successfully exfoliated from bulk crystals grown via chemical vapor transport (CVT). Notably, 2D penta‐PdPS exhibits outstanding electronic and optoelectronic performance under 650 nm laser: high electron mobility of ≈208 cm² V⁻¹ s⁻¹, an ultrahigh on/off ratio of ≈10⁸, a high photoresponsivity of 5.2 × 10⁴ A W⁻¹, a high photogain of 1.0 × 10⁵, an ultrahigh detectivity of 1.0 × 10¹³ Jones, respectively. Significantly, the exceptional puckered pentagonal atomic structure of 2D PdPS makes it strong in‐plane anisotropy in optical, electronic, and optoelectronic properties, demonstrating a sizeable anisotropic ratio of carrier mobility and photocurrent with the value of up to 3.9 and 2.3, respectively. These excellent properties make 2D Cairo Pentagonal PdPS a potential candidate in nanoelectronics, optoelectronics, polarized‐nanoelectronics, which will significantly promote the development of 2D materials.