2D p-Block Main Group Phthalocyanine Monolayers

Abstract

A large class of novel 2D p-block main group phthalocyanine (mgPc) monolayers is discovered for the first time via systematic first-principles calculations and molecular dynamics simulations. 21 newly uncovered semiconductors exhibit exceptional carrier mobility (up to 10⁶ cm² V⁻¹ s⁻¹) and exceed reported values. Axially ligands, biaxial strains, and central atoms are three important degrees of freedom for tuning the properties of the mgPc series. Axially ligands can modulate properties comprehensively, e.g., inducing metal-to-semiconductor transitions and enhancing mobility. Compressive strains gestate 8 Dirac materials featuring three different cone types. Biaxial strain yields diverse semiconductors spanning wide bandgap spectra (0−1.59 eV at HSE06) and conforming to the newly proposed “unimodal model”. The designed semiconductor library provides donor/acceptor candidates for solar cells with record power conversion efficiencies (PCE = 26.28% of PClPc/P(OH)Pc). Solid state adaptive natural density partitioning (SSAdNDP) analysis revealed the presence of electron delocalization within the 16-membered ring of phthalocyanine (16c-2e π-bond), which is unprecedented in 2D materials. The great tunability and high stability of mgPc monolayers pave the way toward diverse applications in flexible electronics, optoelectronics, solar cells, and light harvesting. It is hoped that the work can stimulate the experimental fabrication of these exciting 2D materials.