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Adjusting Aggregation Modes and Photophysical and Photovoltaic Properties of Diketopyrrolopyrrole‐Based Small Molecules by Introducing B←N Bonds
Author(s) -
Pang Shuting,
MásMontoya Miriam,
Xiao Manjun,
Duan Chunhui,
Wang Zhenfeng,
Liu Xi,
Janssen René A. J.,
Yu Gang,
Huang Fei,
Cao Yong
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804020
Subject(s) - molecule , acceptor , materials science , fluorene , fullerene , chromophore , excited state , heterojunction , crystallography , photochemistry , chemical physics , polymer , chemistry , optoelectronics , organic chemistry , atomic physics , physics , composite material , condensed matter physics
The packing mode of small‐molecular semiconductors in thin films is an important factor that controls the performance of their optoelectronic devices. Designing and changing the packing mode by molecular engineering is challenging. Three structurally related diketopyrrolopyrrole (DPP)‐based compounds were synthesized to study the effect of replacing C−C bonds by isoelectronic dipolar B←N bonds. By replacing one of the bridging C−C bonds on the peripheral fluorene units of the DPP molecules by a coordinative B←N bond and changing the B←N bond orientation, the optical absorption, fluorescence, and excited‐state lifetime of the compounds can be tuned. The substitution alters the preferential aggregation of the molecules in the solid state from H‐type (for C−C) to J‐type (for B←N). Introducing B←N bonds thus provides a subtle way of controlling the packing mode. The photovoltaic properties of the compounds were evaluated in bulk heterojunctions with a fullerene acceptor and showed moderate performance as a consequence of suboptimal morphologies, bimolecular recombination, and triplet‐state formation.