Electronic Structure of Metallophthalocyanines, MPc (M = Fe, Co, Ni, Cu, Zn, Mg) and Fluorinated MPc

Abstract

We compute the electronic structure and optical excitation energies of metal-free and transition-metal phthalocyanines (H 2 Pc and MPc for M = Fe, Co, Ni, Cu, Zn, Mg) using density functional theory with optimally tuned range-separated hybrid functionals (OT-RSH). We show that the OT-RSH approach provides photoemission spectra in quantitative agreement with experiments as well as optical band gaps within 10% of their experimental values, capturing the interplay of localized dstates and delocalized π−π* states for these organometallic compounds. We examine the tunability of MPcs and H 2 Pc through fluorination, resulting in quasi-rigid shifts of the molecular orbital energies by up to 0.7 eV. Our comprehensive data set provides a new computational benchmark for gas-phase phthalocyanines, significantly improving upon other density-functional-theory-based approaches.

Mechanistic Investigation of Molybdenum Disulfide Defect Photoluminescence Quenching by Adsorbed Metallophthalocyanines

“…While thermally activated electron transfer processes are typically vibration-coupled and thus require more thermal energy than is available at 10 K ( k B T ≈ 7 cm –1 ), charge transfer can still occur via tunneling . Tunneling-assisted charge transfer strongly depends on the energy level alignment in the heterostructure, which in turn depends on the metal center of the MPc. , Our computed projected density of states (pDOS) of localized defect states (Figure S7a) and orbital energy levels for the MPc and H 2 Pc on MoS 2 (Figure S7b) show the energy of the nonfrontier out-of-plane d-orbital decreasing with increasing atomic number of the metal center. The CoPc HOMO – 1 is near-resonant with the valence band maximum of MoS 2 , suggesting a possible coupling with defect states near the valence band.…”

“…For the electronic structure of mixed-dimensional 0D/2D heterojunctions, an electrostatic model that was found to provide results comparable to those of range-separated hybrid functional calculations and experimental band gaps was used and found to be superior over standard DFT calculations . Specifically, we applied self-energy corrections following Neaton et al , to both the molecular levels of gas-phase phthalocyanine molecules obtained from the optimally tuned range-separated hybrid functional (OT-RSH) and the band edges of MoS 2 to account for the nonlocal dielectric screening effect . Effects of the interface charge redistribution on the energy levels were obtained from DFT calculations with the PBE functional for the 0D/2D heterojunctions.…”

“…Metallophthalocyanines present an ideal system for exploring the chemical control of optically active defects in monolayer MoS 2 . The electronic structures of MPcs can be altered in systematic ways by changing the central metal atom while retaining the aromatic macrocycle framework . In this manner, phthalocyanine–MoS 2 mixed-dimensional heterojunctions have been studied to probe PL quenching, Raman enhancement, ultrafast dynamics, , and interfacial charge transfer and hybridization .…”

Tuning the carrier injection barrier of hybrid metal–organic interfaces on rare earth-gold surface compounds

“…In addition, the DFT+∑ axc method 63,64 was used to determine the HOMO level alignment in CuPc/REAu 2 /Au(111). Further details [65][66][67][68][69][70] can be found in the ESI. †…”

Probing the spin states of tetra‐coordinated iron(II) porphyrins by their vibrational and pre K‐edge x‐ray absorption spectra

“…Over the years, a large amount of effort has been dedicated to understand the spin-state energetics of metalloporphyrins with nearly degenerate spin multiplets . These molecules have been investigated in several works, applying different genres of theoretical methodologies such as Hartree-Fock (HF) [31][32][33], numerous density functional theory based methods [46][47][48][49][50][51][52][53][54][55][56][57][58][59], and multi-reference based methods accounting for static and dynamical correlations, and so forth [34][35][36][37][38][39][40][41][42][43][44][45][46]. Each of the studies has unveiled a difficulty level of the addressed questions and paved the way for their probable solutions.…”