Photovoltaic performance of novel push–pull–push thienyl–Bodipy dyes in solution-processed BHJ-solar cells

Abstract

Original flat push–pull–push dyes have been engineered from thienyl–Bodipy–triphenylamine frameworks for solar cell application.

Synthesis and Spectroscopic Investigation of a Series of Push–Pull Boron Dipyrromethenes (BODIPYs)

“…19, 22 The decreased quantum yield with increase solvent polarity is consistent with previous observations, and is attributed to the increase of nonradiative decay in more polar solvents. 8b, 9a, 9c, 9d, 23 A 2–4 fold decrease in fluorescence quantum yields was observed by comparing BODIPYs 2 to 6a and 6b , 3 to 7 , and 4 to 8 , which can be attributed to the ICT between donors and acceptors 9b, 10 and the internal conversion between narrower band gaps. 24 ICT is known to influence the rate of nonradiative relaxation of fluorophores, resulting in decreased fluorescence quantum yields.…”

“…9,8b For example, the presence of an electron-donating group (e.g., 4-aminophenyl) and an electron-withdrawing group (e.g., 4-methoxycarbonylphenyl) on the BODIPY platform can greatly enhance the charge transfer within the molecule, for potential applications in dye-sensitized solar cells, 7, 10 and two-photon excitation dyes. 2a, 11 These push-pull effects can also significantly red-shift the absorption and emission spectra of BODIPYs to the near-infrared region, therefore making them attractive for biological imaging and biosensing applications.…”

BODIPY‐Based Semiconducting Materials for Organic Bulk Heterojunction Photovoltaics and Thin‐Film Transistors

“…Sutter et al synthesized new BODIPY-based small molecules 18 and 19, which were π-extended with vinyl-thienyl linked triphenylamine moieties ( Figure 2). [54] It has been reported that the attachment of thiophene moieties on the BODIPY π-core improved the efficiency due to high carrier mobility inside the active layer. [50] Also, high open circuit voltage has been demonstrated by linking triphenylamine fragments in the 2,6positions of the BODIPY framework.…”

“…Three novel benzannulated aza-BODIPY dyes with N-methyl pyrrole, N-methyl indole and 2-trimethylsilyl thiophene (53)(54)(55) substituents at α-positions were synthesized by Li et al (Figure 5). [76] These dyes exhibited absorption maxima at 762-793 in solution and at 830-849 nm as thin-film with high molar extinction coefficients.…”

“…Although BODIPYs have very interesting structural/electronic characteristics with a great potential for further advancements in OPV and OTFT applications, a decade ago, they have rarely been studied and generally exhibited very low carrier mobilities (~10 À 5 -10 À 3 cm 2 V À 1 s À 1 ), [37][38][39][40][41][42][43][44][45] and poor photovoltaic performances (PCEs of only 1-2 %). [37,[46][47][48][49][50][51][52][53][54][55] Only very recent efforts in the past five years, including some work from our research groups, have advanced the performance of BODIPY-based materials in (opto) electronics reaching carrier mobilities of~0.01-0.2 cm 2 V À 1 s À 1 and PCEs of~6-9 %. Therefore, detailed knowledge of the upto-date results in BODIPY-based semiconductors, which is the focus of this review, and continuous research into the development of novel BODIPY-based semiconductors is of great importance to broaden the understanding of their charge transport properties and to advance the corresponding device performances.…”