Synthesis and charge carrier photogeneration in novel ladder polymers containing 2,5-thienylene units

Photophysical and Spectroscopic Investigations on (Oligo)Thiophene-Arylene Step-ladder Copolymers. The Interplay of Conformational Relaxation and On-Chain Energy Transfer

“…Comparison of the absorption properties of the investigated step-ladder copolymers with those of the all-phenylene ladder polymer LPPP and the heteroarylene ladder polymer containing 2,5-thienylene units (LPPPT) leads us to the following conclusions: (i) the less structured absorption band of the copolymers contrasts with the very defined and structurally resolved π−π* transition bands observed for LPPP and LPPPT, thus indicating the nonplanar π-system of the copolymers with some conformational freedom; (ii) the λ max abs of the compounds (Table ) are intermediate between the longest λ max abs values for LPPP (446 nm) and LPPPT (532 nm). , This illustrates that a reduction of the optical excitation energy is achieved by the introduction of thienyl units. In contrast to ladder polymers, the conjugation between neighboring repeat units is somewhat decreased in our step-ladder copolymers due to some rotational freedom of the connecting inter-ring single bonds.…”

Combination of Molecular, Morphological, and Interfacial Engineering to Achieve Highly Efficient and Stable Plastic Solar Cells

“…The alternating copolymer poly(2,7‐fluorene‐ alt ‐dithienylbenzothiadiazole) (PFDTBT) has proved to be a promising class of p‐type photoactive material for application in PSCs 15. Considering that forced planarization by covalently fastening adjacent aromatic units in polymer backbone facilitates π‐electron delocalization to narrow the bandgap and suppresses the interannular rotation to enhance intrinsic charge mobility,7, 16–18 we recently reported a PFDTBT‐based analogue, poly(fluorenedicyclopentathiophene‐ alt ‐benzothiadiazole) (PFDCTBT),19 where the 3‐positions of two outer thiophenes are covalently tied with the 3,6‐positions of the central fluorene core by a carbon bridge ( Figure ). The four 4‐(2‐ethylhexoxy)phenyl groups introduced to the fluorenedicyclopentathiophene (FDCT) structure promote the solubility and processing capability of the resulting polymer.…”

Organotin Reagents in Cross‐Coupling Reactions

“…Bras et al [218] synthesized conjugated gels based on thiophene units derived from thiophene and oligothiophene units bearing chloro-and tributylstannyl moieties on the one hand and 1,3,5-tribromobenzene on the other hand. Poly(p-phenylene-co-2,5-thiophenylene) polymers were prepared by Song and Shim [219] and Forster et al [220]. Saadeh et al [221] extended the method by using more complex para-dibromoarenes and two bromoarene moieties linked by a spacer.…”