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

Abstract

Charge transport in crystalline organic semiconductors (OSCs) is considerably hindered by low-frequency vibrations introducing dynamic disorder in the charge transfer integrals. Recently, we have shown that the contributions of various vibrational modes to the dynamic disorder correlate with their Raman intensities and suggested a Raman-based approach for estimation of the dynamic disorder and search for potentially high-mobility OSCs. In the present paper, we showcase this approach by revealing the highest-mobility OSC(s) in two series of crystalline naphthalene diimide derivatives bearing alkyl or cycloalkyl substituents. In contrast to our previous studies, Raman spectra are not measured, but are instead calculated using periodic DFT. As a result, an OSC with a potentially high charge mobility is revealed in each of the two series, and further mobility calculations corroborate this choice. Namely, for the naphthalene diimide derivatives with butyl and cyclopentyl substituents, the estimated room-temperature isotropic electron mobilities are as high as 6 and 15 cm2 V–1 s–1, respectively, in the latter case even exceeding 20 cm2 V–1 s–1 in a two-dimensional plane. Thus, our results highlight the potential of using the calculated Raman spectra to search for high-mobility crystalline OSCs and reveal two promising OSCs, which were previously overlooked.

Structure and properties of naphthalene-diimide N-functionalized with stilbene

“…S15a, ESI†). This is in line with our previous observations 25,26,33,34,65 that considerable values of electron transfer integrals are observed mainly for face-to-face oriented pairs of molecules. The J e value is relatively low as compared with that observed in high-mobility NDI derivatives with (cyclo)alkyl substituents (90–135 meV 25,33 ) but similar to that observed in phenyl-substituted NDIs.…”

“…S15a, ESI †). This is in line with our previous observations 25,26,33,34,65 that considerable values of electron transfer integrals are observed mainly for face-to-face oriented pairs of molecules.…”

“…refs. 25,26,33). In these stacks, charge transfer integrals J (which quantify electronic coupling between the molecules) are large, reaching and even exceeding 100 meV.…”

“…In these stacks, charge transfer integrals J (which quantify electronic coupling between the molecules) are large, reaching and even exceeding 100 meV. 33,34 NDI moieties are also very popular building blocks from small molecules to polymers, including donor-acceptor compounds. 35 However, to the best of our knowledge, the crystal structures of donor-acceptor compounds consisting of NDI N-functionalized (i.e., substituted at the imide position of NDI) with donors are not known.…”

Supramolecular Organization in Salts of Riluzole with Dihydroxybenzoic Acids—The Key Role of the Mutual Arrangement of OH Groups

“…B3LYP [ 56 , 57 ] and PBE-D3 [ 58 , 59 ] are the most popular functionals in periodic (solid-state) DFT calculations of molecular crystals [ 60 , 61 ]. B3LYP and PBE-D3 provide a grounded trade-off between the accuracy and the rate of calculations of experimentally observed properties of molecular crystals [ 62 , 63 , 64 , 65 , 66 , 67 , 68 ]. Computations were conducted using the CRYSTAL17 package [ 69 ].…”