Organic n-Channel Transistors Based on [1]Benzothieno[3,2-b]benzothiophene–Rylene Diimide Donor–Acceptor Conjugated Polymers

Abstract

Improving the charge-carrier mobility of conjugated polymers is important for developing high-performance, solution-processed optoelectronic devices. Although [1]benzothieno[3,2- b]benzothiophene (BTBT) has been frequently used as a high-performance p-type small molecular semiconductor and employed a few times as a building block for p-type conjugated polymers, it has never been explored as a donor moiety for high-performance n-type conjugated polymers. Here, BTBT has been conjugated with either n-type perylene diimide (PDI) or naphthalene diimide (NDI) units to generate a donor-acceptor copolymer backbone, for the first time. Charge-transport measurements of organic field-effect transistors show n-type dominant behaviors, with the electron mobility reaching ∼0.11 cm V s for PDI-BTBT and ∼0.050 cm V s for NDI-BTBT. The PDI-BTBT mobility value is one of the highest among the PDI-containing polymers. The high π-π stacking propensity of BTBT significantly improves the charge-carrier mobility in these polymers, as supported by atomic force microscopy and grazing incidence X-ray diffraction analyses. Phototransistor applications of these polymers in the n-type mode show highly sensitive photoresponses. Our findings demonstrate that incorporation of the BTBT donor unit within the rylene diimide acceptor-based conjugated polymers can improve the molecular ordering and electron mobility.

π-Extended perylene diimide double-heterohelicenes as ambipolar organic semiconductors for broadband circularly polarized light detection

“…More importantly, the slope of photocurrent and V T shift was steeper in p-type mode, indicating improved photosensing responsivity. The higher responsivity is likely originating from the enhanced electrical mobility, which could lead to easier exciton dissociation, exciton separation, and charge transport 59,61 .…”

Lowering the Contact Barriers of 2D Organic F16CuPc Field‐Effect Transistors by Introducing Van der Waals Contacts

“…Most visible‐light OPTs operate on relatively high voltages to deliver high R and D *, whereas F 16 CuPc nanoflake‐based OPT with vdW contact shows superior performance to most visible‐light OPTs even at a very low operating voltage ( V ds = 1 V), which offers new opportunities for emerging photodectectors. [ 41,57–67 ]…”

Near‐Infrared Organic Phototransistors with p‐Channel Photosensitive Layers of Conjugated Polymer Composed of bis‐Octyldodecyl‐Diketopyrrolopyrrole and Benzothiadiazole Units

“…The finally purified PODTPPD-BT polymer exhibited good solubility in a series of solvents (toluene and chlorobenzene (CB)), which can be attributed to the extended length of alkyl groups (octyldodecyl) compared to the ethylhexyl group of the PEHTPPD-BT polymer reported in our previous work. [36] Note that the weight-average molecular weight (M W ) of the PODTPPD-BT polymer (reaction time: 1 h) reached ≈8-10 kDa (depending on the work-up process) with a good polydispersity index (PDI) of 1.3 (see various conjugated polymers with a low PDI (<2) reported to date [44][45][46][47] even though there is a possibility for incomplete polymerization). The PODTPPD-BT films were used as a channel layer in the OFETs with a bottom-gate-top-contact structure (see Figure 1b).…”