Pyrene and Diketopyrrolopyrrole-Based Oligomers Synthesized via Direct Arylation for OSC Applications

Abstract

In this report, an atom efficient and facile synthetic strategy for accessing multi-diketopyrrolopyrrole (DPP)-based oligomers used in solution-processed organic field effect transistors (OFETs) and organic solar cells (OSCs) has been developed. The DPP units were successfully installed onto benzene and pyrene cores via palladium-catalyzed dehydrohalogenative coupling of mono-capped DPPs with multi-bromo-benzene or -pyrene (direct arylation), affording four oligomer small molecules (SMs 1-4) containing bis-, tri-, tri-, and tetra-DPP, respectively, in high yields of 78-96%. All the designed linear or branched DPP-based oligomers exhibit broad light absorptions, narrow band-gaps (1.60-1.73 eV), deep highest occupied molecular orbital (HOMO) levels (-5.26∼-5.18 eV), and good thermal stability (Td=390-401 °C). OFETs based on SMs 1-4 showed hole mobilities of 0.0033, 0.0056, 0.0005, and 0.0026 cm2 V(-1) s(-1), respectively. OSCs based on SMs 1-4 under one sun achieved power conversion efficiencies of 3.00%, 3.71%, 2.47%, and 1.86% accordingly, along with high open-circuit voltages of 0.86-0.94 V. For OSC devices of SM 1, SM 3, and SM 4, the solvent CHCl3 was solely employed to the formation of active layers; neither high boiling point additives nor annealing post-treatment was needed. Such a simple process benefits the large-scale production of OSCs via roll to roll technology.

Improving Photovoltaic Performance of the Linear A-Ar-A-type Small Molecules with Diketopyrropyrrole Arms by Tuning the Linkage Position of the Anthracene Core

“…31 Therefore, DIO additive is favored to promote DPP 2 An(2,6) to exhibit better crystallinity and network, which can further improve carrier transport. 42 In order to further explore the influence of the DIO additive on the film morphology of the blend films, their morphologies were recorded with transmission electron microscopy (TEM). Figure 9 shows the TEM images of the DPP 2 An(2,6)/PC 71 BM (1:1) and DPP 2 An(9,10)/PC 71 BM (1:5) blend films with/ without 1% DIO additive.…”

Synthesis and photovoltaic performance of DPP-based small molecules with tunable energy levels by altering the molecular terminals

“…4, the Ph(DPP-Th) 2 /PC 60 BM and Ph(DPP-Py) 2 / PC 71 BM-based devices exhibited better photovoltaic properties compared to the Ph(DPP-ThCN) 2 /PC 71 BM and Ph(DPP-ThR) 2 / PC 71 BM-based devices, which was attributed to significant increases in the J sc (from 2.11 and 2.21 mA cm À2 to 5.63 and which is higher than the results obtained by Chen for the same blend (3.0%) [6]. As shown in Fig.…”

“…UVeVis absorption spectra were recorded on a HP-8453 UV visible system. Cyclic voltammograms (CV) were carried out on a CHI660A electrochemical work station with a three electrode electrochemical cell in a 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF 6 ) acetonitrile solution with a scan 100 mV s À1 at room temperature (RT) under argon atmosphere. In this three-electrode cell, a platinum rod, platinum wire and Ag/AgCl electrode were used as a working electrode, counter electrode and reference electrode, respectively.…”

“…A smoother surface was observed for the Ph(DPP-Py) 2 based blend film. In general, the smoother morphology indicates finer phase separation, which would promote the exciton dissociation efficiency, resulting in increasing the light response and J sc [6]. Therefore, a higher J sc of 10.55% mA cm…”

Improved photovoltaic performance of D–A–D-type small molecules with isoindigo and pyrene units by inserting different π-conjugated bridge

“…On the other hand, significantly improved high hole-only mobility was achieved by grafting Py unit into the organic photovoltaic. 38,39 Therefore, fused Py group is expected to endow them with a broader light absorption, improved pep interactions of the resulting molecules, and consequently enhanced hole mobility. As a result, incorporating a fused Py unit into conjugated architectures molecule should be improving photovoltaic performances for its resulting molecules.…”