Template‑Assisted Fabrication of Single‑Crystal‑Like Polymer Fibers for Efficient Charge Transport

Polymer semiconductors with highly crystalline forms,such as crystalline nanowires and fibers,are critical for charge carrier transport in organic field-effect transistors(OFET).However,the highly crystalline form usually requires high-quality molecular orderliness,which still remains a great challenge,especially in single fibers of extremely high-molecular-weight semiconducting polymers.In this study,we present an anodic aluminum oxide(AAO)template-assisted method to fabricate highly crystalline N-alkyl diketopyrrolopyrrole dithienylthieno[3,2-b]thiophene(DPP-DTT)single fibers.Grazing-incidence X-ray diffraction and selected area electron diffraction show obvious diffraction patterns for single-crystal-like characteristics,indicating the highly ordered molecular chains and highly crystalline structures of the single DPP-DTT fibers.OFET based on the single-crystal-like DPP-DTT fiber exhibits the highest charge carrier mobility of up to 14.2 cm^(2)V^(−1)s^(-1)and an average mobility of approximately 7.8 cm^(2)V^(−1)s^(-1),which is significantly improved compared with DPP-DTT thin film-based devices.Besides,the fiber-based OFET also exhibit a high light responsivity of 4.0.103 A W^(−1).This work demonstrates a facile and effective method for fabricating single-crystal-like fibers of high-molecular-weight polymer semiconductors and corresponding high-performance OFET devices.Furthermore,it also expands application of AAO template method for achieving crystalline semiconducting polymer fibers and provide a new perspective for the study on polymer crystallization.

Strain-enhanced electrical performance in stretchable semiconducting polymers

Intrinsically stretchable semiconducting polymers are promising candidates for developing wearable electronics,but remain underdeveloped because the correlation between the microstructural evolution during stretching and the resultant charge transport is not clearly understood.In this study,we clarify the impact of molecular orientation on the dynamic performance of stretched semiconducting polymers,controlling molecular orientations via solvent-dependent spin-coating.We found that strainenhanced electrical performance is feasible by quelling disorders within the face-on-packed aggregates.Strain facilitates 3D ordering in face-on-packed films,but increase theπ-πorientation disorders and lamellar dislocation in the edge-on analogue,which contribute inversely to the charge transport.Consequently,the face-on samples maintain strain-resistant energetic disorder and a 1.5×increase in on-current,achieving a 10-times-higher retention than the edge-on analogue upon 100%strain.Furthermore,we developed a reliable way for measuring the photoelectrical stretchability of semiconducting polymer.This study contributes to developing high-performance stretchable semiconducting polymers.