Alternating copolymers of diketopyrrolopyrrole or benzothiadiazole and alkoxy-substituted oligothiophenes: Spectroscopic, electrochemical and spectroelectrochemical investigations
PBN-AR
Instytucja
Wydział Chemiczny (Politechnika Warszawska)
Informacje podstawowe
Główny język publikacji
en
Czasopismo
Electrochimica Acta
ISSN
0013-4686
EISSN
Wydawca
Pergamon
DOI
Rok publikacji
2014
Numer zeszytu
Strony od-do
211-220
Numer tomu
144
Liczba arkuszy
0.5
Autorzy
Pozostali autorzy
+ 4
Autorzy przekładu
(liczba autorów przekładu: 0)
Słowa kluczowe
en
benzothiadiazole-oligothiophene copolymers; copolymers; diketopyrrolopyrrole-oligothiophene; model; organic semiconductors; Raman spectroelectrochemistry vibrational; UV-vis-NIR spectroelectrochemistry
Streszczenia
Język
en
Treść
A series of solution processable semiconducting donor-acceptor (DA) copolymers consisting of either diketopyrrolopyrrole or benzothiadiazole A units and alkoxy- or alkyl-substituted oligothiophene D units were synthesized. For all prepared copolymers the measured XPS spectra (C1s, S2p, N1s and O1s) were in a very good agreement with the expected chemical constitution. Spectroscopic studies of the synthesized copolymers showed that their optical band gaps were governed by the presence of the alkoxy substituents whose electron donating properties led to additional gap narrowing yielding semiconductors with band gaps of below 1.3 eV in the case of the polymers with the diketopyrrolopyrrole A unit. The same trend was observed with the electrochemical band gaps, whose values were however found to be ca. 0.4 eV superior to the corresponding optical band gaps values. Vibrational model was calculated for two of the synthesized copolymers with the goal to unequivocally attribute the observed Raman modes and to support the interpretation of the spectral changes induced by the electrochemical oxidation. It was established that the electrochemical oxidative doping of the copolymer with the benzothiadiazole A unit is limited to the oligothiophene segment in which the charge of the formed polycation is localized. To the contrary, in the case of the polymer with the diketopyrrolopyrrole A segment the charge imposed on the oligothiophene segment delocalizes towards the diketopyrrolopyrrole unit. These findings are in perfect agreement with the UV-vis-NIR spectroelectrochemistry data which show strong localization of electrochemically created charge carriers in the benzothiadiazole - oligothiophene copolymer and their metallic-like delocalization in the diketopyrrolopyrrole one. The latter seems to be very interesting not only as a potential low band gap component of organic photovoltaic cells but also, in the doped state, as electronic conductor of metallic character. © 2014 Elsevier Ltd.
Inne
System-identifier
WUTc5bc2d4e3d1e43fe8de4c28b1e79bc92
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