Influence of Various Doping Agents on Organic Semiconductors' Physicochemical Properties

Due to the electron-reach pi-conjugated organic semiconductors system, chemical so-called p-type doping is easily achievable. Oxidation by some molecules, atoms, or ions called "dopants" or "doping agents" force the molecule to accept the positive electrical charge. In general, there are several "theoretical" ways to increase the conductivity of the semiconductors by the introduction, as mentioned above, of the charge carriers into the structure of the molecule. For this reason, it was designed and synthesized a model molecule possessing: (a) acidic hydrogen-a fragment able to undergo chemical oxidation; (b) a unit having a pi-excess ring-vulnerable to electrochemical oxidation; (c) a free electron pair-susceptible to protonation and methylation; and finally (d) a fragment that is Lewis base in nature-that is, it can form adducts with Lewis acid. In this paper, we are reporting a comprehensive study (with the aid of DFT calculation) concerning the different doping agents' influence on physicochemical properties of the model (namely 2,5-bis(2-(2-thienyl)-thien-5-yl)thiazolo[5,4-d]thiazole) organic semiconductor.