High Aspect Ratio Conjugated Polymer Nanowires for High Performance Field-Effect Transistors and Phototransistors

Abstract

We synthesized a highly crystalline DPP-based polymer, DPPBTSPE, which contained 1,2-bis(5-(thiophen-2-yl)selenophen-2-yl)ethene as a planar and rigid electron donating group. High- and low-molecular weight (MW) DPPBTSPE fractions were collected by Soxhlet extraction and were employed to investigate their unique charge transport properties in macroscopic films and single crystalline polymer nanowire (SC-PNW), respectively. The low-MW polymer could provide well-isolated and high aspect ratio SC-PNWs, in which the direction of π-π stacking was perpendicular to the wire growing axis. The field effect transistors made of SC-PNWs exhibited remarkably high carrier mobility of 24 cm(2) V(-1) s(-1). In addition, phototransistors (PTs) made of SC-PNW showed very high performance in terms of photoresponsivity (R) and photoswitching ratio (P). The average R of the SC PNW-based PTs were in the range of 160-170 A W(-1) and the maximum R was measured at 1920 A W(-1), which is almost three orders higher than that of thin film-based PT device.

Conjugated polymer single crystals and nanowires

“…Later, Choi et al prepared nanowires of a more planar DPP‐based polymer bearing 1,2‐bis(5‐[thiophen‐2‐yl]‐selenophen‐2‐yl)ethene in the repeating group, as shown in Figure A . They used high‐ and low‐ M w polymers to grow nanowires and found that the resulting nanowires made of high‐ M w polymer were much shorter and wider than those made of low‐ M w polymer.…”

“…(A) SEM images of high‐ and low‐ M w DPP‐based polymer bearing 1,2‐bis(5‐[thiophen‐2‐yl]‐selenophen‐2‐yl)ethane (DPPBTSPE) nanowires. (Adapted from Reference with permission from Copyright 2015 American Chemical Society). (B) SEM images of PDPP2TBDT and PDPP2TzBDT nanowires; a schematic diagram of molecular packing in the one‐dimensional nanocrystals is shown.…”

“…For DPP‐based polymers, the highest mobility of single nanowire FET was achieve 24 cm 2 /vs . Interestingly, Wang et al found that both edge‐on and face‐on orientations of DPP‐based polymer nanowires showed high mobility .…”

Diketopyrrolopyrrole‐based polymer nanowires: Control of chain conformation and nucleation

“…Among many promising conjugated polymers, diketopyrrolopyrrole (DPP)‐based polymer is one of the most famous polymers due to its excellent performance . Preparing DPP‐based polymer nanowires is very important because the width of nanowires could be changed, which is very important to the improvement of device performance . However, only several DPP‐based polymer nanowires have been reported in very dilute solution (0.01 mg/mL) .…”

“…Preparing DPP‐based polymer nanowires is very important because the width of nanowires could be changed, which is very important to the improvement of device performance . However, only several DPP‐based polymer nanowires have been reported in very dilute solution (0.01 mg/mL) . DPP‐based polymer nanowires in higher concentration solutions (>0.1 mg/mL) were firstly prepared by our group through a way called SEOMS .…”