Pentacene Disproportionation during Sublimation for Field-Effect Transistors

Abstract

At moderate temperatures in flowing gas, pentacene undergoes a disproportionation reaction to produce 6,13-dihydropentacene (DHP) and a series of polycondensed aromatic hydrocarbons, including the previously unknown peripentacene (PP). The process requires activation by heating to 320 degrees C and is possibly catalyzed by impurities such as DHP, 6,13-pentacenequinone (PQ), Al, or Fe found in the starting materials. These impurities also result in a decrease in the intrinsic field-effect mobility (FEM) of pentacene crystals. Subsequent purifications remove such impurities, thus inhibiting the formation of the disproportionation products and increasing the FEM of pentacene (2.2 cm(2)/Vs). These results clarify the importance of purification of semiconductive materials for measurements of intrinsic mobility and optimal device performance.

Recent Progress in Quinoidal Singlet Biradical Molecules

“…The amount of singlet biradical character (y) of [m.n]periacene was calculated by using the index defined by Yamaguchi 30 coupled to the symmetry-broken UBHandHLYP/6-31G* calculation. peripentacene, was detected in the gas phase by mass spectroscopy, 52 and the isolation of a derivative was also attempted by Müllen et al 53 For understanding the singlet biradical character of [3.n]periacenes, namely anthenes, the resonance formula consisted of Kekulé and biradical forms is helpful (Figure 14). In the formula, two unpaired electrons appear on both meso-positions of anthenes, when one draws the structure with a maximum number of Clar sextets, and at the same time, the bonds denoted by a assume double bond character.…”

Density functional theory study on electron and hole transport properties of organic pentacene derivatives with electron‐withdrawing substituent

“…The electronic couplings of these dimers were calculated based on the entire dimer Hamiltonian model. The mobilities along the specific directions of these dimers, the angular resolution anisotropic mobilities and some experimental results of the mobilities [20,33,35,[53][54][55] were listed in Table 2.…”

“…According to the energy splitting in dimer (ESID) model the transfer integral for charge carriers is usually taken as half the energy difference of the [a] Tang, M. L. et al [29] [b] Roberson, L. B. et al [53] [c] Reese, C. et al [20] [d] Lee, S. et al [54] [e] Sakamoto, Y. et al [35] [f ] Tang, M. L. et al [33] S. Chai et al…”

“…[20,53,56] Another possible reason is the difference between transport in the bulk and interface of organic semiconductors. [57] Theoretical simulations which ignore the experimental details offer a reasonable analysis of the charge transport properties of the semiconductor materials though and predict the preferred design of the organic electronic devices.…”

Organic Field-Effect Transistor: Device Physics, Materials, and Process

“…Pentacene (1), as the benchmark of organic semiconductors, was first reported in 1970s, but the numerous OFET applications were only conducted recently [37,38]. With strong intermolecular interactions and herringbone packing motif, pentacene exhibits efficient charge transport.…”