Effect of Molecular Structure of α,α′-Dialkylquaterthiophenes and Their Organosilicon Multipods on Ordering, Phase Behavior, and Charge Carrier Mobility

Abstract

We report on bulk structures of a family of quaterthiophene (4T) derivatives with linear and branched end groups such as α,α'-dihexylquaterthiophene (Hex-4T-Hex), α,α'-didecyl-quaterthiophene (Dec-4T-Dec) and α,α'-bis(2ethylhexyl)quaterthiophene (EH-4T-EH), tetramethyldisiloxane-based dimers D2-Und-4T-EH and D2-Und-4T-Hex, and carbosilane-siloxane-based tetramers D4-Und-4T-EH and D4-Und-4T-Hex. The dimers and tetramers contain undecylenic (Und) spacers between the disiloxane and 4Tunits of the molecule. The impact of the molecular architecture on the bulk structure at different temperatures is addressed with X-ray diffraction and differential scanning calorimetry. For all the studied quaterthiophenecontaining organosilicon multipods the formation of 4T-crystal sub-lattice is observed. The alkyl periphery plays an important role in the molecular packing and thermal stability of the ordered phase. They can stabilize or destabilize the crystal phase, depending on their length and architecture. The quaterthiophenes with 2-ethylhexyl end groups adopt a zig-zag conformation in the crystalline state at room temperature. This change of conformation leads to a significant decrease of the polymorphic transition and isotropization temperatures. The efficiency of 4T packing in the sub-lattice is estimated from the molecular cross-section (S) in the plane normal to the molecular axis. Correlations between S and field-effect charge carrier mobility are established.

Integrated molecular, morphological and interfacial engineering towards highly efficient and stable solution-processed small molecule solar cells

“…† All oligomers at the rst heating exhibit single, sharp and strong endothermic peaks, as well as relatively high values of melting temperature (T m ) and melting enthalpy (DH m ), which indicates their crystalline nature. 32 The oligomer without alkyls at the DCV unit, DTS(Oct) 2 -(2T-DCV) 2 , has the highest T m in this series of molecules (Table 1). However, its DH m was found to be 69 J g À1 , which is signicantly less as compared to the nearest analog with methyl-DCV terminal groups having a DH m of 90 J g À1 .…”

Achievements in polycondensation and condensation polymers

“…Many publications concern systematic research into the effect of the chemical structures of the initial components containing various substituents-for example, fluorine, allyl, undecyl, hydroxyl, and mesogenic groups-and the number of generations on the architecture of dendrimers and their ordering, phase state, rheology, and mobilities of charge carriers [222,[223][224][225][226][227][228][229][230][231][232][233][234].…”

Атомный Состав И Стабильность Монослоев Ленгмюра-Блоджетт На Основе Силоксанового Димера Кватертиофена На Поверхности Поликристаллического Золота

“…Структурные и электронные свойства ультратонких пленок на основе молекул олиготиофенов представля-ют значительный интерес в связи с возможностью их использования в устройствах органической электрони-ки [1][2][3]. Пленочные материалы на основе политиофе-нов и олиготиофенов обладают относительно высокой подвижностью носителей заряда и вместе с тем демон-стрируют высокую термическую и термоокислительную стабильность [1,4].…”

“…Таким образом, органического полу-проводникового слоя толщиной в 1−2 молекулы на поверхности подложки достаточно для формирования проводящего канала ОПТ. Одним из наиболее перспек-тивных методов создания поверхностных структур на основе олиготиофенов является метод самосборки из раствора, который позволяет получать кристаллические монослои с относительно высокой подвижностью но-сителей заряда (self-assembled monolayers) [2][3][4][5]. Од-нако самосборка монослоя из раствора -длитель-ный процесс, который может занимать десятки часов до достижения полного покрытия подложки, поэтому его масштабирование затруднительно.…”