Impact of Fluoroalkylation on the n-Type Charge Transport of Two Naphthodithiophene Diimide Derivatives

Abstract

In this work, we investigate two recently synthesized naphthodithiophene diimide (NDTI) derivatives featuring promising n-type charge transport properties. We analyze the charge transport pathways and model charge mobility with the non-adiabatic hopping mechanism using the Marcus-Levich-Jortner rate constant formulation, highlighting the role of fluoroalkylated substitution in α (α-NDTI) and at the imide nitrogen (N-NDTI) position. In contrast with the experimental results, similar charge mobilities are computed for the two derivatives. However, while α-NDTI displays remarkably anisotropic mobilities with an almost one-dimensional directionality, N-NDTI sustains a more isotropic charge percolation pattern. We propose that the strong anisotropic charge transport character of α-NDTI is responsible for the modest measured charge mobility. In addition, when the role of thermally induced transfer integral fluctuations is investigated, the computed electron–phonon couplings for intermolecular sliding modes indicate that dynamic disorder effects are also more detrimental for the charge transport of α-NDTI than N-NDTI. The lower observed mobility of α-NDTI is therefore rationalized in terms of a prominent anisotropic character of the charge percolation pathways, with the additional contribution of dynamic disorder effects.

Computational discovery of high charge mobility self-assembling π-conjugated peptides

“…43 range from 1.45 to 3.36 cm 2 Vs −1 , which is at least ∼550% higher than our best reported mobility of 0.224 cm 2 Vs −1 in Lib-BDT spacer 0. On the other hand, the electron mobility of NDTI derivatives ranges from 0.24 to 0.39 cm 2 Vs −1 , 84 which is only ∼71% higher than our highest electron mobility of 0.143 cm 2 Vs −1 in Lib-PDI spacer 0. We note that our predicted charge mobilities pertain to electron/hole transport along the π-cores in individual stacks of π-conjugated peptides and are commensurate with prior experimental reports of charge mobility within organic semiconductor nanowire structures.…”

“…5b). In comparison, the transfer integral values for NDTI derivatives of 38–46 meV were reported at COM distances of 4.2 Å, 84 which is the same order of magnitude as our Lib-PDI spacer 0 that possess transfer integral values of 76 meV at COM separations of ∼3.41 Å.…”

“…As a point of comparison, the reorganization energy of dinaphthoij2,3-b:2′,3′-f ]thienoij3,2-b]thiophene (DNTT) and its derivatives, which are widely employed in organic electronic devices, 82,83 range from 75 meV to 188 meV, 43 which is about 55 meV (22%) lower than our best reported reorganization energy in Lib-BDT spacer 0 (243 meV). On the other hand, the reorganization energy for naphthodithiophene diimide (NDTI), a recently synthesized derivative of widely studied n-type semiconductors NDI, 81 is around 286 meV, 84 which is around 26% lower than our measured Lib-NDI spacer 1 (388 meV) and only 4% lower than the Lib-PDI spacer 1 (301 meV).…”

High-Mobility Naphthalene Diimide Derivatives Revealed by Raman-Based In Silico Screening

“…Note that the six crystals considered in this work ( Figure 1 ) were characterized by Z red = 1, unlike the crystals of NDI and naphthodithiophene diimide derivatives with Z red = 2, for which electron mobility has recently been studied, both experimentally and theoretically [ 66 , 67 ].…”

Towards a fast machine-learning-assisted prediction of the mechanoelectric response in organic crystals

“…We start by characterising charge transfer pathways in the crystal. 49,50 This was achieved by identifying all nonequivalent homodimers formed by a given molecule with its nearest neighbours and computing the corresponding electronic couplings. The C10-DNBDT-NW crystal (see Fig.…”