Influence of the oxidation level on the electronic, morphological and charge transport properties of novel dithienothiophene S-oxide and S,S-dioxide inner core oligomers

Influence of the oxidation level on the electronic, morphological and charge transport properties of novel dithienothiophene S-oxide and S,S-dioxide inner core oligomers

Novel inner-core dithienothiophene S-oxide and S, S-dioxide oligomers were designed and synthesized. The controlled oxidation at the central sulfur of the dithienothiophene core allows the combined tailoring of the HOMO-LUMO energies, thermal properties, and thin film morphology. Electrochemical measurements indicate that a marked decrease in electron affinity is obtained by addition of the first oxygen at the central sulfur, while addition of the second oxygen induces only minor effects on both the oxidation and reduction potentials. The newly synthesized materials exhibit high solubility in common organic solvents together with good film forming properties when deposited on SiO2 by solution-based techniques. Similar hole field effect transistor (FET) mobility for solution-deposited and thermally-evaporated films together with FET performances independent of film morphology and molecular orientation call for non-conventional charge transport mechanisms.

设计并合成了新型内核二噻吩并噻吩S -氧化物和S,S -二氧化物低聚物。对二噻吩并噻吩核心的中心硫进行可控氧化，可以对最高占据分子轨道 - 最低未占分子轨道（HOMO - LUMO）能级、热性能和薄膜形态进行综合调控。电化学测量表明，在中心硫上添加第一个氧会使电子亲和能显著降低，而添加第二个氧对氧化电位和还原电位的影响都较小。新合成的材料在普通有机溶剂中具有高溶解度，并且当通过溶液法沉积在二氧化硅上时具有良好的成膜性能。溶液沉积和热蒸发薄膜具有相似的空穴场效应晶体管（FET）迁移率，并且FET性能与薄膜形态和分子取向无关，这需要非常规的电荷传输机制。