Preferential Face-on and Edge-on Orientation of Thiophene Oligomers by Rational Molecular Design.

Precise control over the supramolecular organization of organic semiconducting materials guiding to exclusive face-on or edge-on orientation is a challenging task. In the present work, we study the preferential packing of thiophene oligomers induced through rational molecular designing and self-assembly. The acceptor-donor-acceptor-type oligomers having 2-(1,1-dicyano-methylene)rhodanine as acceptor (OT1) favored a face-on packing, whereas that of functionalized with N-octyl rhodanine (OT2) preferred an edge-on packing as evident from 2D-grazing incidence angle X-ray diffraction, tapping-mode atomic force microscopy (AFM) and Raman spectroscopy analyses.

Computer-Aided Screening of Conjugated Polymers for Organic Solar Cell: Classification by Random Forest.

Owing to the diverse chemical structures, organic photovoltaic (OPV) applications with a bulk heterojunction framework have greatly evolved over the last two decades, which has produced numerous organic semiconductors exhibiting improved power conversion efficiencies (PCEs). Despite the recent fast progress in materials informatics and data science, data-driven molecular design of OPV materials remains challenging. We report a screening of conjugated molecules for polymer-fullerene OPV applications by supervised learning methods (artificial neural network (ANN) and random forest (RF)).

Following the TRMC Trail: Optimization of Photovoltaic Efficiency and Structure-Property Correlation of Thiophene Oligomers.

Semiconducting conjugated oligomers having same end group (N-ethylrhodanine) but different central core (thiophene: OT-T, bithiophene: OT-BT, thienothiophene: OT-TT) connected through thiophene pi-linker (alkylated terthiophene) were synthesized for solution processable bulk-heterojunction solar cells. The effect of the incorporation of an extra thiophene to the central thiophene unit either through C-C bond linkage to form bithiophene or by fusing two thiophenes together to form thienothiophene on the optoelectronic properties and photovoltaic performances of the oligomers were studied in detail. Flash photolysis time-resolved microwave conductivity (FP-TRMC) technique shows OT-TT has significantly higher photoconductivity than OT-T and OT-BT implying that the former can outperform the latter two derivatives by a wide margin under identical conditions in a bulk-heterojunction solar cell device.