RESUMEN
Charge transport in organic semiconductors occurs via overlapping molecular orbitals quantified by transfer integrals. However, no statistical study of transfer integrals for a wide variety of molecules has been reported. Here we present a statistical analysis of transfer integrals for more than 27,000 organic compounds in the Cambridge Structural Database. Interatomic transfer integrals were used to identify substructures with high transfer integrals. As a result, thione and amine groups as in thiourea were found to exhibit high transfer integrals. Such compounds are considered as potential non-aromatic, water-soluble organic semiconductors.
The analysis of interatomic transfer integrals for 27,718 organic compounds revealed that thione (S=R)amine (NR3) and thionethione interactions tend to increase transfer integrals and are suitable to highmobility organic semiconductors.
RESUMEN
Asymmetric liquid-crystal (LC) organic semiconductors, such as 2-decyl-7-(p-tolyl)-[1]benzothieno[3,2-b][1]benzothiophene (pTol-BTBT-C10), exhibit high mobilities exceeding 10 cm2 V-1 s-1. The LC phases play important roles in thermal stability and self-assembly ordering during film deposition and annealing. In this study, we show molecular dynamics simulations of pTol-BTBT-C10 and reveal a unique mechanism of the molecular flip-flop motion at the smectic E/smectic B phase transition.
RESUMEN
Organic thin-film transistors using small-molecule semiconductor materials such as 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-P) have been recently studied for the production of flexible and printed electronic devices. Blending a semiconductor with an insulating polymer, such as polystyrene, is known to improve the device performance; however, its molecular-level structure remains unknown. In this study, we performed molecular dynamics (MD) simulations on a mixed system of TIPS-P and atactic polystyrene (aPS) with fully atomistic models to understand the structure of the mixed thin film at the molecular level and the influence on the device properties. To reproduce the deposition from the solution, we gradually reduced the number of toluene molecules in the simulation. The dynamic characteristics of the system, mean squared displacement, diffusion coefficient, density profile, and P2 order parameter were analyzed. Some of the simulated systems reached the equilibrium state. In these systems, the simulated structures suggested the presence of more TIPS-P molecules on the surface than inside the bulk, even at the low molecular weight of aPS, where phase separation was not observed experimentally. The results of the fully atomistic MD simulations are also a basis for the coarse-grained model to increase the speed of the MD simulation.