Quantum localization and delocalization of charge carriers in organic semiconducting crystals

Giannini, Samuele; Carof, Antoine; Ellis, Matthew; Yang, Hui; Ziogos, Orestis George; Ghosh, Soumya; Blumberger, Jochen

doi:10.1038/s41467-019-11775-9

Cited by 165 publications

(214 citation statements)

References 64 publications

Supporting

Mentioning

200

Contrasting

Order By: Relevance

“…Figure 3a illustrates the charge carrier wavefunction and transport mechanism in the TL regime; for a realistic visualization on an actual molecular system see ref. 33 , which also provides a recent validation of the TL scenario by an independent theoretical method. When disorder is so strong that the carriers become localized on a single molecular site, Eq.…”

Section: In Inorganic Semiconductors Including the Observation Of Anmentioning

confidence: 98%

Charge transport in high-mobility conjugated polymers and molecular semiconductors

et al. 2020

View full text Add to dashboard Cite

Conjugated polymers and molecular semiconductors are emerging as a viable semiconductor technology in industries such as displays, electronics, renewable energy, sensing and healthcare. A key enabling factor has been significant scientific progress in improving their charge transport properties and carrier mobilities, which has been made possible by a better understanding of the molecular structure-property relationships and the underpinning charge transport physics. Here we aim to present a coherent review of how we understand charge transport in these high-mobility van der Waals bonded semiconductors. Specific questions of interest include estimates for intrinsic limits to the carrier mobilities that might ultimately be achievable; a discussion of the coupling between charge and structural dynamics; the importance of molecular conformations and mesoscale structural features; how the transport physics of conjugated polymers and small molecule semiconductors are related; and how the incorporation of counterions in doped films-as used, for example, in bioelectronics and thermoelectric devices-affects the electronic structure and charge transport properties.

show abstract

Section: In Inorganic Semiconductors Including the Observation Of Anmentioning

confidence: 98%

Charge transport in high-mobility conjugated polymers and molecular semiconductors

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The methodology is based on a DFT-parametrized tight-binding representation of the electronic Hamiltonian (updated on-the-fly) to naturally incorporate local and non-local electron-phonon couplings, thus encompassing in a non-perturbative manner a broad range of possible transport mechanisms. In two previous applications, this method has proven very successful in predicting charge mobility in organic single crystals using 1D models for specific crystallographic directions [33] as well as for columnar crystal phases of tetracene derivatives. [34] In this work we further improve the efficiency of our FOB-SH methodology by using a multiple time step algorithm to reduce the computational cost without sacrificing accuracy.…”

mentioning

confidence: 99%

“…At the other extreme, standard band theory calculations tend to strongly overestimate mobility in all systems, as discussed previously. [33] Mobilities from transient localization theory (TLT) are reported in Figure S6, Supporting Information, and compared to mobilities from FOB-SH and experiment (see Supporting Information for details). We note that the TLT mobilities are in excellent agreement with FOB-SH and experiment but only if the diagonal disorder is excluded in the calculation of the localization length (green symbols).…”

mentioning

confidence: 99%

Flickering Polarons Extending over Ten Nanometres Mediate Charge Transport in High‐Mobility Organic Crystals

Giannini

Ziogos

Carof

et al. 2020

Advcd Theory and Sims

Self Cite

View full text Add to dashboard Cite

Progress in the design of high‐mobility organic semiconductors has been hampered by an incomplete fundamental understanding of the elusive charge carrier dynamics mediating electrical current in these materials. To address this problem, a novel fully atomistic non‐adiabatic molecular dynamics approach termed fragment orbital‐based surface hopping (FOB‐SH) that propagates the electron‐nuclear motion has been further improved and, for the first time, used to calculate the full 2D charge mobility tensor for the conductive planes of six structurally well characterized organic single crystals, in good agreement with available experimental data. The nature of the charge carrier in these materials is best described as a flickering polaron constantly changing shape and extensions under the influence of thermal disorder. Thermal intra‐band excitations from modestly delocalized band edge states (up to 5 nm or 10–20 molecules) to highly delocalized tail states (up to 10 nm or 40–60 molecules in the most conductive materials) give rise to short, ≈ 10 fs‐long bursts of the charge carrier wavefunction that drives the spatial displacement of the polaron, resulting in carrier diffusion and mobility. This study implies that key to the design of high‐mobility materials is a high density of strongly delocalized and thermally accessible tail states.

show abstract

“…Using Marcus theory in this manner is similar to other recent high throughput methods which have evaluated structures using these types of properties. 11 As an assessment of its predictive power against a more complete description of charge transport, we carried out comparisons of Marcus theory against mobilities from nonadiabatic molecular dynamics [36][37][38][39][40][41] (see Table S2 and Figure S4, ESI † for details) for a series of functionalised tetracenes. 41 These results indicate a good correlation for the majority of structures across the range of mobilities, but occasional outliers where Marcus theory predictions are poor.…”

Section: Electron Mobility Calculationsmentioning

confidence: 99%

Evolutionary Chemical Space Exploration for Functional Materials: Computational Organic Semiconductor Discovery

Cheng¹,

Campbell²,

Day

2020

Preprint

View full text Add to dashboard Cite

Computational methods, including crystal structure and property prediction, have the potential to accelerate the materials discovery process by enabling structure prediction and screening of possible molecular building blocks prior to their synthesis. However, the discovery of new functional molecular materials is still limited by the need to identify promising molecules from a vast chemical space. We describe an evolutionary method which explores a user specified region of chemical space to identify promising molecules, which are subsequently evaluated using crystal structure prediction. We demonstrate the methods for the exploration of aza-substituted pentacenes with the aim of finding small molecule organic semiconductors with high charge carrier mobility, where the space of possible substitution patterns is too large to exhaustively search using a high throughput approach. The method efficiently explores this large space, typically requiring calculations on only ca.1% of molecules during a search. The results reveal two promising structural motifs: aza-substituted naphtho[1,2-a]anthracenes with reorganisation energies as low as pentacene and a series of pyridazine-based molecules having both low reorganisation energies and high electron affinities.

show abstract

Quantum localization and delocalization of charge carriers in organic semiconducting crystals

Cited by 165 publications

References 64 publications

Charge transport in high-mobility conjugated polymers and molecular semiconductors

Charge transport in high-mobility conjugated polymers and molecular semiconductors

Flickering Polarons Extending over Ten Nanometres Mediate Charge Transport in High‐Mobility Organic Crystals

Evolutionary Chemical Space Exploration for Functional Materials: Computational Organic Semiconductor Discovery

Contact Info

Product

Resources

About