Fundamental Gaps of Condensed-Phase Organic Semiconductors from Single-Molecule Calculations using Polarization-Consistent Optimally Tuned Screened Range-Separated Hybrid Functionals

2018 ◽  
Vol 14 (12) ◽  
pp. 6287-6294 ◽  
Author(s):  
Srijana Bhandari ◽  
Margaret S. Cheung ◽  
Eitan Geva ◽  
Leeor Kronik ◽  
Barry D. Dunietz
2019 ◽  
Author(s):  
Michel Rickhaus ◽  
Michael Jirasek ◽  
Lara Tejerina ◽  
Henrik Gotfredsen ◽  
Martin D. Peeks ◽  
...  

<div><p>Aromaticity is an important concept for predicting electronic delocalisation in molecules, particularly for designing organic semiconductors and single-molecule electronic devices. It is most simply defined by the ability of a cyclic molecule to sustain a ring current when placed in a magnetic field. Hückel’s rule states that if a ring has [4n+2] π-electrons, it will be aromatic with an induced magnetisation that opposes the external field inside the ring, whereas if it has 4n π-electrons, it will be antiaromatic with the opposite magnetisation. This rule reliably predicts the behaviour of small molecules, typically with circuits of less than about 22 π-electrons (n = 5). It is not clear whether aromaticity has a size limit and whether Hückel’s rule is valid in much larger macrocycles. Here, we present evidence for global aromaticity in a wide variety of porphyrin nanorings, with circuits of up to 162 π-electrons (n = 40; diameter 5 nm). We show that aromaticity can be controlled by changing the molecular structure, oxidation state and three-dimensional conformation. Whenever a global ring current is observed, its direction is correctly predicted by Hückel’s rule. The magnitude of the current is maximised when the average oxidation state of the porphyrin units is around 0.5–0.7, when the system starts to resemble a conductor with a partially filled valence band. Our results show that aromaticity can arise in large macrocycles, bridging the size gap between ring currents in molecular and mesoscopic rings.</p></div>


2016 ◽  
Vol 18 (10) ◽  
pp. 7521-7526 ◽  
Author(s):  
Sujin Ham ◽  
Sang Hyeon Lee ◽  
Heejae Chung ◽  
Dongho Kim

The photophysical properties of a series of highly π-conjugated benzoporphyrin molecules (BPNs) with different shapes were investigated in the condensed phase using single-molecule fluorescence spectroscopy.


2022 ◽  
Author(s):  
David Huang ◽  
Huong Nguyen

We derive a systematic and general method for parametrizing coarse-grained molecular models consisting of anisotropic particles from fine-grained (e.g. all-atom) models for condensed-phase molecular dynamics simulations. The method, which we call anisotropic force-matching coarse-graining (AFM-CG), is based on rigorous statistical mechanical principles, enforcing consistency between the coarse-grained and fine-grained phase-space distributions to derive equations for the coarse-grained forces, masses, and moments of inertia in terms of properties of a condensed-phase fine-grained system. We verify the accuracy and efficiency of the method by coarse-graining liquid-state systems of two different anisotropic organic molecules, benzene and perylene, and show that the parametrized coarse-grained models more accurately describe properties of these systems than previous anisotropic coarse-grained models parametrized using other methods that do not account for finite-temperature and many-body effects on the condensed-phase coarse-grained interactions. The AFM-CG method will be useful for developing accurate and efficient dynamical simulation models of condensed-phase systems of molecules consisting of large, rigid, anisotropic fragments, such as nucleic acids, liquid crystals, and organic semiconductors.


2013 ◽  
Vol 15 (8) ◽  
pp. 083045 ◽  
Author(s):  
Adrian Keller ◽  
Janina Kopyra ◽  
Kurt V Gothelf ◽  
Ilko Bald

2005 ◽  
Vol 03 (supp01) ◽  
pp. 205-213 ◽  
Author(s):  
TIEN-SUNG LIN ◽  
DAVID J. SLOOP ◽  
CHUNG-YUAN MOU

The possibility of utilizing highly polarized electron spin of the photo-excited triplet state of organic semiconductors (pentacene molecules) embedded in organic crystals and mesoporous materials by zero-field (ZF) and near zero-field (NZF) pulsed electron paramagnetic resonance (EPR) techniques in a quantum computer will be explored. A simple logic gate, such as CNOT, utilizing such highly polarized electron spins communicating with the surrounding paramagnetic nuclei via hyperfine interaction will be discussed. Major advantages of these approaches are: (1) high electron spin polarization, (2) possible single-molecule detection, (3) orchestrated quantum perturbations can be imposed, and (4) pulsed ZF and NZF EPR techniques can be performed without high magnetic field.


2015 ◽  
Vol 629 ◽  
pp. 29-35 ◽  
Author(s):  
W.E.B. Shepherd ◽  
R. Grollman ◽  
A. Robertson ◽  
K. Paudel ◽  
R. Hallani ◽  
...  

2019 ◽  
Author(s):  
Michel Rickhaus ◽  
Michael Jirasek ◽  
Lara Tejerina ◽  
Henrik Gotfredsen ◽  
Martin D. Peeks ◽  
...  

<div><p>Aromaticity is an important concept for predicting electronic delocalisation in molecules, particularly for designing organic semiconductors and single-molecule electronic devices. It is most simply defined by the ability of a cyclic molecule to sustain a ring current when placed in a magnetic field. Hückel’s rule states that if a ring has [4n+2] π-electrons, it will be aromatic with an induced magnetisation that opposes the external field inside the ring, whereas if it has 4n π-electrons, it will be antiaromatic with the opposite magnetisation. This rule reliably predicts the behaviour of small molecules, typically with circuits of less than about 22 π-electrons (n = 5). It is not clear whether aromaticity has a size limit and whether Hückel’s rule is valid in much larger macrocycles. Here, we present evidence for global aromaticity in a wide variety of porphyrin nanorings, with circuits of up to 162 π-electrons (n = 40; diameter 5 nm). We show that aromaticity can be controlled by changing the molecular structure, oxidation state and three-dimensional conformation. Whenever a global ring current is observed, its direction is correctly predicted by Hückel’s rule. The magnitude of the current is maximised when the average oxidation state of the porphyrin units is around 0.5–0.7, when the system starts to resemble a conductor with a partially filled valence band. Our results show that aromaticity can arise in large macrocycles, bridging the size gap between ring currents in molecular and mesoscopic rings.</p></div>


2019 ◽  
Author(s):  
Michel Rickhaus ◽  
Michael Jirasek ◽  
Lara Tejerina ◽  
Henrik Gotfredsen ◽  
Martin D. Peeks ◽  
...  

<div><p>Aromaticity is an important concept for predicting electronic delocalisation in molecules, particularly for designing organic semiconductors and single-molecule electronic devices. It is most simply defined by the ability of a cyclic molecule to sustain a ring current when placed in a magnetic field. Hückel’s rule states that if a ring has [4n+2] π-electrons, it will be aromatic with an induced magnetisation that opposes the external field inside the ring, whereas if it has 4n π-electrons, it will be antiaromatic with the opposite magnetisation. This rule reliably predicts the behaviour of small molecules, typically with circuits of less than about 22 π-electrons (n = 5). It is not clear whether aromaticity has a size limit and whether Hückel’s rule is valid in much larger macrocycles. Here, we present evidence for global aromaticity in a wide variety of porphyrin nanorings, with circuits of up to 162 π-electrons (n = 40; diameter 5 nm). We show that aromaticity can be controlled by changing the molecular structure, oxidation state and three-dimensional conformation. Whenever a global ring current is observed, its direction is correctly predicted by Hückel’s rule. The magnitude of the current is maximised when the average oxidation state of the porphyrin units is around 0.5–0.7, when the system starts to resemble a conductor with a partially filled valence band. Our results show that aromaticity can arise in large macrocycles, bridging the size gap between ring currents in molecular and mesoscopic rings.</p></div>


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