Electron delocalization in single-layer phthalocyanine-based covalent organic frameworks: a first principle study

Abstract

A series of single-layer phthalocyanine-based covalent-organic frameworks (COFs) are shown to possess tunable delocalized electronic states which are attractive for optoelectronic applications.

Ultrathin porphyrin and tetra-indole covalent organic frameworks for organic electronics applications

“…where e is the elementary charge, ̵ h is the reduced Planck constant, k B is the Boltzmann constant, T is the temperature of the system, m * is the effective mass of the carrier, C 2D is the in-plane stiffness, and E 1 is the Bardeen-Shockley deformation potential (DP). 40,44,[63][64][65] Hole and electron effective masses are calculated via quadratic fitting of the valence band (VB) and conduction band (CB) extrema, respectively. Although the utilization of the PBE XC functional is known to underestimate the electronic bandgap, 66 the morphology of the band structure is consistent with results from hybrid XC functionals.…”

“…Although the utilization of the PBE XC functional is known to underestimate the electronic bandgap, 66 the morphology of the band structure is consistent with results from hybrid XC functionals. 40,44 As a result, all m * values are evaluated using PBE calculations. Moreover, both C 2D and E 1 are calculated at the PBE level of theory by means of elastic uniaxial deformations (±0.5% and ±1.0% strain) along the in-plane lattice vector directions.…”

“…The dependency of the band structure on the twofold linker type is also examined, elucidating this way the tunability of electronic properties upon different core and linker combinations. On a different level of core interconnection, the effect of core fusion via conjugation extensions on electronic and CT properties has been demonstrated by Gutzler 43 for metal-free phthalocyanine and Pham et al 44 for nickel phthalocyanine derivatives, revealing direct-gap semiconducting behavior with sizable charge mobilities. We demonstrate that all fused TIP-2H systems under study exhibit semi-metallic behavior, in contrast to their phthalocyanine analogs.…”

“…The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp extended π-conjugation, has been examined in the literature via DFT simulations. [42][43][44][45] The selection of the systems under study is mainly inspired by the phenomenal synthetic versatility of porphyrin-based nanostructures already realized in the literature. [46][47][48][49][50] In this work, we focus on the determination of electronic and CT properties of ultrathin COF structures based on fourfold metal-free porphyrin (P) and tetra-indole porphyrinoid cores, 51,52 linked either via variable articulated twofold spacers or through proper aromatic ring fusion as to avoid unfavorable steric hindrances.…”

The electronic structures and magnetic properties of mixed-valence Fe-based metal–organic VNU-15 frameworks: a theoretical study from linear response DFT+U calculations

“…The mobility of photogenerated electrons and holes has been investigated in a previous study. 49 Based on a nearly free electron approximation, the mobility of photoexcited carriers can be calculated via the following formula:…”