Azido-Functionalized Thiophene as a Versatile Building Block To Cross-Link Low-Bandgap Polymers

Abstract

We unveil a concept for the design of crosslinkable semiconducting polymers that is based on a modular tercopolymerization which stands out by its low synthetic effort, easy accessibility, and its broad range of applications. 3-(6-Azidohexyl)thiophene was used as a comonomer in the synthesis of a variety of low-bandgap copolymers using different polymerization techniques such as Suzuki−Miyaura cross-coupling and Stille cross-coupling. We show that when only a small amount (5−10 mol %) of azide groups is introduced into the polymers, the impact on absorption and electrochemical properties (HOMO/LUMO values) is negligible. The small amount of azide functionality is however enough to obtain polymers that can easily be cross-linked by UV illumination. Thermal stability of the solid state packing and alignment is studied in neat polymer thin films as well as in blends with [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 70 BM) as a relevant model blend system. Solvent resistivity of these polymer films is investigated by absorption and photoluminescence measurements. It is finally shown in organic field effect transistors that the introduction of 10% azide-functionalized monomer does not considerably influence hole transport mobility (0.20−0.45 cm 2 V −1 s −1 ).

Crosslinked Semiconductor Polymers for Photovoltaic Applications

“…Similar observations with regard to small amounts of functional groups were also made by several other groups . A noteworthy example is the work by Chen et al, who obtained a PCE of 6.06% using only 2.5% of crosslinkable vinyl‐groups in PBDTTPD‐V x (Figure ) combined with PC 71 BM, still retaining 91% of the efficiency after 40 h of annealing at 150 °C.…”

“…This work is discussed in more detail in the next section. Further work was performed on bromine containing low bandgap polymers, [23] azide functionalized copolymers [24] as well as on a series of PBT derivatives including bromine, azide, and vinyl units. [25] In the polymers discussed above, the crosslinkable groups are attached to the polymer side chain.…”

“…[16,21,22,24,34] A noteworthy example is the work by Chen et al, who obtained a PCE of 6.06% using only 2.5% of crosslinkable vinyl-groups in PBDTTPD-V x ( Figure 2) combined with PC 71 BM, still retaining 91% of the efficiency after 40 h of annealing at 150 °C. This is among the highest PCEs reported for OPVs using crosslinked active layers.…”

A comprehensive nano-interpenetrating semiconducting photoresist toward all-photolithography organic electronics

“…The mobility reaches up to 1.64 cm 2 V −1 s −1 , which is the highest value of photocrosslinkable OSCs reported until now (Fig. 2E) (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31).…”

Electro‐Oxidative Coupling of Azoles with 2‐ and 3‐Haloindoles/Thiophenes Providing Access to 2/3‐Halo(Azol‐1‐Yl)Indoles/Thiophenes

“…The indole/thiophene ring systems are ubiquitous presence in biologically active compounds (such as Celogentin C and Zyprexa Zydis) and functional materials. [1] Thus, extensive efforts have been devoted to expand the diversity of modification or functionalization of these scaffolds. [2] As the rapid development of transition metal-catalyzed transformation over the past decade, a large number of methods on CÀ X functionalization of indole/thiophene core were developed.…”