Two-dimensional deformation potential model of mobility in small molecule organic semiconductors

An acoustic deformation potential model appropriate for transport in two dimensions is employed to estimate upper limits on the intrinsic hole mobility of DNTT-C-10 [2,9-dialkyl-dinaphtho[2,3-b: 2',3'-f] thieno[3,2-b] thiophene] and BTBT-C-12 [2,7-dialkyl[1] benzo-thieno[3,2-b][1] benzothiophene]. First-principles calculations are employed to determine the values of effective masses, deformation potentials, and elastic constants entering the model. The analysis suggests that the upper limit on room temperature mobility within a single crystalline region in DNTT-C-10 or BTBT-C-12 may be some tens of cm(2)/Vs. The width of the pi-bonded molecular core in the direction perpendicular to the transport plane is identified as a structural feature affecting mobility in two-dimensional organic semiconductors. (C) 2011 American Institute of Physics. [doi:10.1063/1.3624588]