Deformation Effect on the Electrical Properties of a Flexible Organic Semiconductor composed of Poly(dimethylsiloxane) and Multiwalled Carbon Nanotubes

Abstract

advances in organic semiconductors have fueled many of the developments in the fi eld of fl exible electronics. [9][10][11][12] In comparison with the conventional organic semiconductors, blending organic polymers with low dimension conductive materials seems able to offer the great possibility to construct the devices with high conductivity and controllability. [13][14][15][16] Poly(dimethylsiloxane) (PDMS), a typical example of insulating organic polymers, has always been a very popular material for the fabrication of fl exible electronic devices for its numerous advantages including high elasticity, good stability, and biocompatibility. However, in most cases, PDMS is usually taken on as substrates of fl exible devices. [17][18][19][20] Composites merging together the excellent properties of low dimension conductive materials and PDMS with the high tunability have a rich prospect in different research fi elds, yet the reports are much fewer. [21][22][23][24] Currently, lots of efforts have been made in research of low dimension conductive fi llers, such as carbon nanotubes (CNTs) and graphene, for their unique properties and potential applications. [25][26][27][28] CNTs, which are hollow, cylindrical nanometer-sized fi bers with high aspect ratio, charge carrier mobility, and fl exibility, are promising candidates for fl exible electronics. [29][30][31][32] In our previous work, we presented a fl exible polymer semiconductor composed of PDMS and multiwalled carbon nanotubes (MWNTs), and researched the contacts in the metal/composite junctions for the fi rst time. The Coulomb gap variable range hopping (CG VRH) model could satisfactorily explain the semiconductor behavior in the composites, and Schottky diodes prepared by curing the 0.35 wt% composite between gold (Au) and copper (Cu) electrodes showed a typical P-type rectifi ed behavior with a high Schottky barrier height (SBH) of 0.78 eV. Field effect transistors with a high effective mobility of 1.98 cm 2 V −1 s −1 and photovoltaic devices with a stable open-circuit voltage of 0.4 V have been fabricated by taking advantage of the semiconductor property of the 0.35 wt% composite. These results suggest that the MWNT-PDMS composites can be treated as usual P-type semiconductors and can Organic semiconductors are the main elements for the development of fl exible electronics due to their excellent fl exibility and large-area manufacturing at low cost. Here, the effect of deformation on the electrical properties of a highly fl exible organic semiconductor composed of poly(dimethylsiloxane) and multiwalled carbon nanotubes is investigated. The results reveal that their resistances increase with increasing deformation quantities, and in contrast to the outcomes of the compressed samples, the resistances of the higher multiwalled carbon nanotube loading composites show greater changes than those of the lower ones under certain bending angles or stretching ratios. Moreover, the property of the 0.35 wt% (the percolation threshold of the composite) sample is highly st...