205105-15-3Relevant academic research and scientific papers
Development of novel n-Type materials based on benzothiadiazole derivatives for organic photovoltaics: Effects of acceptor terminal substituents
Shibata, Yosei,Kono, Takahiro,Usui, Hiroyo,Yoshida, Yuji
supporting information, p. 680 - 682 (2015/05/27)
Novel n-type materials of BTD-CN (1) and BTD-CF3 (2) were synthesized for organic photovoltaics. Both materials show approximately the same HOMO-LUMO level and position of absorption peaks. However, the organic photovoltaic performance of a device with 1 is clearly higher than that with 2. In this paper, we discuss the effects of terminal substituents on film morphology, crystallinity, and photovoltaic performance. The results suggest that cyano-modified benzothiadiazole is useful because of its crystallinity, carrier recombination, and series resistance.
Regiochemically well-defined fluorenone-alkythiophene copolymers: Synthesis, spectroscopic characterization, and their postfunctionalization with oligoaniline
Demadrille, Renaud,Rannou, Patrice,Bleuse, Joel,Oddou, Jean-Louis,Pron, Adam
, p. 7045 - 7054 (2007/10/03)
A new solution processable, regioregular, alternate copolymer of fluorenone and dialkyl-bithiophene, namely poly[(5,5′-(3,3′-di-n-octyl-2,2′-bithiophene))-alt-(2,7-fluore n-9-one)] (abbreviated as PDOBTF), was synthesized by three different preparation methods: chemical or electrochemical oxidation of 2,7-bis(4-octylthien-2-yl)-fluoren-9-one or polycondensation of 2,7-bis(5-bromo-4-octylthien-2-yl)-fluoren-9-one in the presence of Ni(0) reagent. Independent of the preparation method, the crude product is a mixture of high molecular weight fractions and short oligomers. It can be however easily fractionated into fractions differing in their molecular weight by sequential extractions with a series of solvents. The principal absorption band registered for the undoped polymer (λmax = 384 nm for the THF solution and 389 nm for the solid state) originates from the π-π* transition of the conjugated backbone and is blue-shifted because of the chain torsion effects caused by steric hindrance. This band is accompanied by a peak of smaller intensity (λmax = 476 nm for the THF solution and 485 nm for the solid state) attributed to the n-π* transition in the carbonyl group of the fluoren-9-one subunit. Preliminary photoluminescence studies show that PDOBTF exhibits a very large Stokes shift and emits red light (λmax = 631 nm in THF solution and 643 nm in the solid state). Upon chemical p-type doping with FeCl4-, the polymer reaches the conductivity of σdc = 0.05 S cm-1. Moessbauer spectroscopy studies of the doping process show that both structural subunits, i.e., the bithiophene subunit and the fluoren-9-one one, participate in the doping. PDOBTF can be relatively easily postfunctionalized by grafting aniline oligomers as pendant groups via the carbonyl groups of the fluoren-9-one subunit. By consequence, the spectrum of the modified polymer can be precisely tuned in the visible region by changing the grafting level.
