Quasiparticle Electronic Structure of Two-Dimensional Heterotriangulene-Based Covalent Organic Frameworks Adsorbed on Au(111)

TL;DR

This study uses advanced first-principles calculations to explore the electronic properties of 2D heterotriangulene-based COFs on gold surfaces, revealing how interfaces influence their electronic structure for potential electronic applications.

Contribution

It applies the dielectric embedding GW method to accurately analyze the quasiparticle electronic structure of heterotriangulene-based COFs on Au(111), including interface effects.

Findings

Interface dielectric screening modulates band energies and shapes.

Results agree with experimental energy level measurements.

Many-body effects influence effective masses and Fermi velocity.

Abstract

The modular nature and unique electronic properties of two-dimensional (2D) covalent organic frameworks (COFs) make them an attractive option for applications in catalysis, optoelectronics, and spintronics. The fabrications of such devices often involve interfaces formed between COFs and substrates. In this work, we employ the first-principles GW approach to accurately determine the quasiparticle electronic structure of three 2D carbonyl bridged heterotriangulene-based COFs featuring kagome lattice, with their properties ranging from a semi-metal to a wide-gap semiconductor. Moreover, we study the adsorption of these COFs on Au(111) surface and characterize the quasiparticle electronic structure at the heterogeneous COF/Au(111) interfaces. To reduce the computational cost, we apply the recently developed dielectric embedding GW approach and show that our results agree with existing experimental measurement on the interfacial energy level alignment. Our calculations illustrate how the many-body dielectric screening at the interface modulates the energies and shapes of the kagome bands, the effective masses of semiconducting COFs, as well as the Fermi velocity of the semi-metallic COF.