Synthetic Nuances to Maximize n-Type Organic Electrochemical Transistor and Thermoelectric Performance in Fused Lactam Polymers

Abstract

A series of fully fused n-type mixed conduction lactam polymers p(g 7 NC n N) , systematically increasing the alkyl side chain content, are synthesized via an inexpensive, nontoxic, precious-metal-free aldol polycondensation. Employing these polymers as channel materials in organic electrochemical transistors (OECTs) affords state-of-the-art n-type performance with p(g 7 NC 10 N) recording an OECT electron mobility of 1.20 × 10 –2 cm 2 V –1 s –1 and a μ C * figure of merit of 1.83 F cm –1 V –1 s –1 . In parallel to high OECT performance, upon solution doping with (4-(1,3-dimethyl-2,3-dihydro-1 H -benzoimidazol-2-yl)phenyl)dimethylamine (N-DMBI), the highest thermoelectric performance is observed for p(g 7 NC 4 N) , with a maximum electrical conductivity of 7.67 S cm –1 and a power factor of 10.4 μW m –1 K –2 . These results are among the highest reported for n-type polymers. Importantly, while this series of fused polylactam organic mixed ionic–electronic conductors (OMIECs) highlights that synthetic molecular design strategies to bolster OECT performance can be translated to also achieve high organic thermoelectric (OTE) performance, a nuanced synthetic approach must be used to optimize performance. Herein, we outline the performance metrics and provide new insights into the molecular design guidelines for the next generation of high-performance n-type materials for mixed conduction applications, presenting for the first time the results of a single polymer series within both OECT and OTE applications.

Highly Efficient Mixed Conduction in N‐type Fused Small Molecule Semiconductors

“…In addition, the reduced π‐stack d ‐spacing did not bring about the improvement of carrier mobility, in this case, we postulate that π‐stacking is not the key factor affecting the carrier mobility in the NB system, but the 3D charge transport caused by the dual orientation of edge‐on and face‐on plays an important role. In the previous NB‐based polymers, [ 40,66 ] the carrier mobility of the polymers with mixed orientation is higher than that of the polymers with an edge‐on orientation, which is consistent with our results. Notably, different from the charge transport in OFETs, where closer π–π stacking facilities the electron charge transport, [ 29 ] while the charge conduction in OECTs is dominated by the bulk doping as well as ions transport.…”

Switching p-type to high-performance n-type organic electrochemical transistors via doped state engineering

“…Device configuration: W/L = 100/10 μm. Comparison of the h μC * and μ , and i τ on and μ values of P(gTDPP2FT) with other reported n-type OECT materials 25 , 27 – 30 , 38 , 45 . …”

“…The μC* and μ of P(gTDPP2FT) are both record values, and the response times are among the shortest in n-type OECT materials (Fig. 3h, I and Table S3 ) 25 , 27 – 30 , 38 , 45 .

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“…This “lowering LUMO” strategy effectively enhances electron mobility and has promoted the fast development of n-type OFETs 16 – 24 . Inspired by this strategy, in the last 3 years, several strong electron-deficient n-type building blocks have been designed and used for OECTs, including naphthalene diimide (NDI) 9 , 11 , 25 , benzodifurandione-based oligo( p -phenylene vinylene) (BDOPV) 26 , bithiophene imide (BTI) 27 , 28 , pyrazine-flanked diketopyrrolopyrrole (PzDPP) 11 , 7,7′-diazaisoindigo (AIG) 29 , and some ladder-type polymers 15 , 30 . The μC * of the n-type OECT materials have been greatly enhanced from less than 0.1 F cm −1 V −1 s −1 to over 10 F cm −1 V −1 s −1 9 , 28 .…”

High Performance Gold Nanorods@DNA Self-Assembled Drug-Loading System for Cancer Thermo-Chemotherapy in the Second Near-Infrared Optical Window

“…However, one major obstacle, to date, is the limited choice of contrast agents in this spectral range. Common PTAs, including organic dyes [ 14 , 15 ], carbon nanomaterials [ 16 , 17 ], inorganic semiconductor materials [ 18 , 19 ], and precious metal materials [ 20 , 21 ], in this window are largely uncharacterized for their cytotoxicity. Among them, AuNPs, a precious metal material, have received widespread attention based on their outstanding physical and chemical properties, good biocompatibility, and excellent local surface plasmon resonance (LSPR) properties.…”