Insight into in-plane isotropic transport in anthracene-based organic semiconductors

Abstract

A molecular design strategy for developing anthracene-based organic semiconductors with in-plane isotropic mobility.

Effect of Alkyl Chain Length on Charge Transport Property of Anthracene-Based Organic Semiconductors

“…The threshold voltages ( V th ) of forward and reverse sweeps were shifted to the negative direction as the successive measurements asymptotically reach a steady value, as shown in Figure S12. This is a normal phenomenon in OFETs − due to the dynamic formation of interface traps. , Obviously, the hysteresis leads to the significant differences in mobility and V th between the first and second scans of forward sweeps, but it presents a slight effect on the reverse sweeps and remains almost at the same value for the forward and reverse sweeps on the third scan, which is considered a static state of the interface traps. , Thereby, the mobility and other relevant OFET characteristics of C n -Ph-Ants were calculated from the saturation regime of the reverse sweep on the third scan (Figure a), as summarized in Table . The corresponding output curves of C n -Ph-Ants are shown in Figure S13.…”

“…The reason for the increase of transfer integral at slipped parallel contacts with the increase of the alkyl chain length from 0 (6.37 meV) to 3 (13.7 meV) is that a large torsion angle between the phenyl rings and the anthracene core can suppress the π–π intermolecular interaction and vice versa. In addition, the transfer integrals of C 0 - and C 2 -Ph-Ants between neighboring molecules were conducted with Amsterdam Density Function (ADF) software using PW91 functional (GGA:PW91) and the basis set of double-Z 2 plus polarization functions (DZ2P) in our previous work, as shown in Figure S16a. Figure S16b shows the calculated angular resolution mobilities of C 0 and C 2 -Ph-Ants based on the Marcus–Hush equation. − C 0 and C 2 -Ph-Ants exhibited maximum mobilities of 0.61 and 0.27 cm 2 V –1 s –1 with similar anisotropy ratios of 1.38 and 1.4, respectively.…”

Insight into the effect of alkyl chain length and substituent bulkiness on the mobility anisotropy of benzothieno[3,2-b][1]benzothiophenes

“…For example, DHTAnt has shown LHB-IS with balanced transfer integrals ( V P = 20.6 meV, V T = 29.7 meV), which leads to a low anisotropic ratio of 1.09 in angular resolution mobility (ARM) calculations. 13 2,6-bis(4-methoxyphenyl)-anthracene (BOPAnt) showed LHB-IS with imbalanced transfer integrals ( V P = 10.9 meV, V T = 33.7 meV), whereas it still exhibited a low anisotropic ratio of 1.49 in ARM calculations. The calculated results of BOPAnt matched well with the nearly isotropic charge mobility of SC-OFETs range of 13.4–16.6 cm 2 V −1 s −1 (the anisotropic ratio = 1.24) in the experiments.…”

Aromatic Ring Overlap Pedals the Nature of Exciton Coupling and Carrier Transport in a Series of Electron-Deficient Anthracenes

“…Among the several acenes (naphthalene, anthracene, tetracene, pentacene) with highly planar π-conjugated skeletons, anthracene is one of the highly studied chromophores in several optical devices. − It encompasses three fused phenyl rings that possess (i) a preferably greater extended π-conjugated skeleton with better intramolecular orbital overlap (compared to naphthalene), which facilitates better charge transport, (ii) comparatively higher stability, and (iii) better solubility in common solvents, among all the other acenes. Though some anthracene derivatives with excellent p-type carrier mobility in single-crystal − and film state OFETs , were known, very few reports are known for their ambipolar derivatives. , Here, we report a series of anthracene derivatives (Figure ) substituted with an electron-withdrawing group (−CF 3 ) to facilitate a lower lowest unoccupied molecular orbital (LUMO) energy level with enhanced stability under ambient conditions. The σ-electron-withdrawing CF 3 group is expected to facilitate lowering of the LUMO energy and eventually would ensure air-stability of the molecules. , It is also known that the position of substitution in the π-electron skeleton of the anthracene core has a great impact on the excitation energies, especially the oscillator strength which strongly affects the spectral properties .…”