Effects of the Substituents of Boron Atoms on Conjugated Polymers Containing B←N Units

Abstract

Organoboron chemistry is a new tool to tune the electronic structures and properties of conjugated polymers, which are important for applications in organic optoelectronic devices. To investigate the effects of substituents of boron atoms on conjugated polymers, we synthesized three conjugated polymers based on double B←N-bridged bipyridine (BNBP) with various substituents on the boron atoms. By changing the substituents from four phenyl groups and two phenyl groups/two fluorine atoms to four fluorine atoms, the BNBP-based polymers show blue-shifted absorption spectra, decreased LUMO/HOMO energy levels, and enhanced electron affinities, as well as increased electron mobilities. Moreover, these BNBP-based polymers can be used as electron acceptors for all-polymer solar cells. These results demonstrate that substituents of boron atoms can effectively modulate the electronic properties and applications of conjugated polymers.

Boron–nitrogen substituted dihydroindeno[1,2-b]fluorene derivatives as acceptors in organic solar cells

“…More economically feasible, environmentally stable and easily tunable (in terms of optoelectronic and physical properties) acceptor materials are therefore desirable and this is where boron and BN doped conjugated molecules have seen the most promise. Most of the focus to date has been on well-studied BODIPY-based frameworks 15 or boron containing subpthalocyanines, [16][17][18][19] but more recently boron-nitrogen bipyridine derivatives 20,21 have demonstrated high device performances.…”

Panchromatic Organoboron Molecules with Tunable Absorption Spectra

“…The synthetic routes of the seven organoboron compounds are depicted in Scheme . The dibromide of the three organoboron core units ( 1 ) were synthesized following the procedures in our previous paper . The boronates of the π‐bridging unit with aldehyde substituents ( 2 ) were prepared according to literature methods .…”

“…The dibromide of the organoboron core units and the borates of the π-bridging units with aldehyde substituent were prepared according to literature methods. [8,9,10] General procedures for Suzuki coupling reaction and Knoevenagel condensation are as follows. The synthetic details are provided in the Supporting Information.…”

“…Toluene and tetrahydrofuran were purified by distillation under argon prior to use. The dibromide of the organoboron core units and the borates of the π‐bridging units with aldehyde substituent were prepared according to literature methods . General procedures for Suzuki coupling reaction and Knoevenagel condensation are as follows.…”

“…The dibromide of the three organoboron core units (1) were synthesized following the procedures in our previous paper. [8,9] The boronates of the π-bridging unit with aldehyde substituents (2) were prepared according to literature methods. [10] Suzuki coupling between the dibromide of the organoboron core units and the boronates of the π-bridging unit with aldehyde substituents gave the key intermediates (3).…”