Complementary Semiconducting Polymer Blends: Influence of Side Chains of Matrix Polymers

A comprehensive investigation of four polydiketopyrrolopyrroles (PDPPs) with increasing ethylene glycol (EG) content and varying nature of comonomer is presented, and guidelines for the design of efficient mixed ion‐electron conductors (MIECs) are deduced. The studies in NaCl electrolyte‐gated organic electrochemical transistors (OECTs) reveal that a high amount of EG on the DPP moiety is essential for MIEC. The PDPP containing 52 wt% EG exhibits a high volumetric capacitance of 338 F cm−3 (at 0.8 V), a high hole mobility in aqueous medium (0.13 cm2 V−1 s−1), and a μC* product of 45 F cm−1 V−1 s−1. OECTs using this polymer retain 97% of the initial drain‐current after 1200 cycles (90 min of continuous operation). In a cell growth medium, the OECT‐performance is fully maintained as in the NaCl electrolyte. In vitro cytotoxicity and cell viability assays reveal the excellent cell compatibility of these novel systems, showing no toxicity after 24 h of culture. Due to the excellent OECT performance with a considerable cycling stability for 1200 cycles and an outstanding cell compatibility, these PDPPs render themselves viable for in vitro and in vivo bioelectronics.

Section: Resultsmentioning

confidence: 99%

Polydiketopyrrolopyrroles Carrying Ethylene Glycol Substituents as Efficient Mixed Ion‐Electron Conductors for Biocompatible Organic Electrochemical Transistors

Thelakkat

Meichsner

Hochgesang

et al. 2021

“…Correlation length, as measured in the stacking direction (ξ para ) and in the lamellae direction (ξ perp ) constitute another point to discuss, as variable tendencies have already been published as a function of the alkyl‐to‐siloxane substitution. [ 16,24,28,31,74 ] For semiconducting polymers, indeed, ξ para is the most pertinent parameter, as it corresponds to the crystallite sizes as measured in the π‐stacking planes. ξ perp is also a meaningful value in lamellar mesomorphic polymers, as it reflects the regularity of the lamellar layers on top of each other.…”

Section: Resultsmentioning

confidence: 99%

On the Impact of Linear Siloxanated Side Chains on the Molecular Self‐Assembling and Charge Transport Properties of Conjugated Polymers

Narayanaswamy

Ibraikulov

Durand

et al. 2020

Herein reported is the impact of the functionalization of four different semiconducting polymer structures by a linear siloxane‐terminated side‐chains. The latter is tetrasiloxane (Si4) or trisiloxane (Si3) chains, substituted at their extremity to a pentylene linker. The polymer structure is based on 5,6‐difluorobenzothiadiazole comonomer (PF2), a diketopyrrolopyrrole unit (PDPP‐TT), a naphtalediimide unit (PNDI‐T2), and a poly[bis(thiophen‐2‐yl)thieno[3,2,b]thiophene (PBTTT). The properties of these siloxane‐functionalized polymers are scrutinized and compared with the ones of their alkyl‐substituted polymer analogues. The impact of the alkyl‐to‐siloxane chain substitution clearly depends on the molecular section of the side chains. When a branched 2‐octyldodecyl chain (C20) is replaced by a Si4 chain of same molecular section, the greatest impact is the strong increase of the π‐stacking overlap of the polymer backbones. This effect leads to a significative enhancement of the charge mobility values of the polymers. As in‐plane and out‐of‐plane mobility are increased simultaneously, this π‐overlap enhancement effect happens to be preponderant over the polymer orientation variations. When a linear tetradecyl chain (C14) is replaced by a linear Si3 chain of twice larger molecular section, the polymer structure is profoundly affected. While PBTTT‐C14 is crystalline and purely edge‐on, PBTTT‐Si3 is mesomorphic and shows a mixed face‐on/edge‐on orientation.

“…The field of intrinsically stretchable polymer semiconductor has witnessed significant growth in recent years [23] . Various structural modification strategies have been reported, such as backbone engineering [24] [25] and side-chain engineering [26] [27] , which include flexible conjugation breakers [28] , longer and softer side chain [29] , or tuning the size and number of electron-donating thiophene groups [30] . The general design principle is to decrease the overall crystallinity of the polymer film while maintaining good electrical connections between aggregates, thus maintaining good charge transport.…”

Section: Introductionmentioning

confidence: 99%

An Intrinsically Stretchable High‐Performance Polymer Semiconductor with Low Crystallinity

Zheng

Wang

Kang

et al. 2019

142

218

For wearable and implantable electronics applications, developing intrinsically stretchable polymer semiconductor is advantageous, especially in the manufacturing of large-area and high-density devices. A major challenge is to simultaneously achieve good electrical and mechanical properties for these semiconductor devices. While crystalline domains are generally needed to achieve high charge carrier mobilities, amorphous domains are necessary to impart stretchability. Recent progresses in the design of high-performance donor-acceptor polymers which exhibited low degrees of energetic disorder, while having high fraction of amorphous morphology, appears promising for polymer semiconductors. Here, a low crystalline, i.e. near-amorphous, indacenodithiophene-co-benzothiadiazole (IDTBT) polymer and a semi-crystalline thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTT) are compared, for mechanical properties and electrical performance under applied strains. It is observed that the low crystalline IDTBT is able to achieve both high modulus and high fracture strain, and to preserve electrical functionality under high strain. Next, fully stretchable transistors are fabricated using the IDTBT polymer, and observed mobility ~0.6 cm 2 V-1 s-1 at 100% strain along stretching direction. In addition, the morphological evolution of the stretched IDTBT films is investigated by polarized UV-Vis and GIXD to elucidate the molecular origins of high ductility. In summary, the nearamorphous IDTBT polymer signifies a promising direction regarding molecular design principles toward intrinsically stretchable high-performance polymer semiconductor.