Facilely Accessible Porous Conjugated Polymers toward High-Performance and Flexible Organic Electrochemical Transistors

Abstract

Porous morphologies have shown great potential in optimizing the capacitance and charge carrier transport for semiconducting polymers in organic electrochemical transistors (OECTs). Nevertheless, it remains arduous and time-consuming to obtain such desired microstructures due to the requirement of rigorous humidity control and templates/additives. Herein, three new glycolated conjugated polymers based on a fused-ring cyclopentadithiophene (CPDT) skeleton are developed, which feature readily obtained large-area porous thin films via spin-casting from binary solvent mixtures under ambient conditions. These polymers afford fascinating capacitances reaching a maximum of 353 F cm −3 , which is the highest value reported to date for p-type OECT materials. The optimal combination of volumetric capacitance and hole mobility in a representative polymer enables the fabrication of OECTs with a high μC* value up to 476 F cm −1 V −1 s −1 and a current retention of 98% upon 600 switching cycles. Moreover, the corresponding flexible OECTs exhibit exceptional mechanical stability at various bending radii down to 5 mm and under repetitive bending cycles. This work provides a simple yet effective binary solvent strategy to fabricate porous conjugated polymers for high-performance OECTs and flexible devices, which will further advance the development of organic mixed ionic−electronic conductors in OECT research fields and beyond.

High-Transconductance, Highly Elastic, Durable and Recyclable All-Polymer Electrochemical Transistors with 3D Micro-Engineered Interfaces

“…Notably, an impressive ON/OFF ratio that approached ~ 10 4 and a maximum G m of 2.3 mS were realized. These values were again comparable to those of a prior metal-electrode-based device [ 34 ]. Therefore, this gelatin-based electrolyte with patterned PEDOT:PSS/LiTFSI microelectrodes could provide a versatile soft platform for high-transconductance OECTs that would be compatible with a broad range of active channel materials.…”

“…S5c–e). Rather than limit our work to PEDOT:PSS-based materials, we also attached a thin poly(triethylene glycol cyclopenta[2,1-b:3,4-b′]dithiophene-monoethylene glycol bithiophene) (P3gCPDT-1gT2) [ 34 ] layer to the channel region and demonstrated operation of an enhancement-mode all-polymer OECT with high flexibility (Figs. 3 d and S5f).…”

“…Gelatin (GEL, ~ 240 g Bloom), glycerol (GLY, ≥ 99.5%), sodium citrate (Na 3 Cit, 98%) bis(trifluoromethane)sulfonimide lithium salt (LiTFSI, 99%), glucose oxidase, and glucose (96%) were purchased from Aladdin Chemical Reagent Co., Ltd. PEDOT:PSS (PH1000, 1.1–1.3 wt.% solid content) was purchased from Heraeus Co., Ltd. Polydimethylsiloxane (PDMS, Sylgard 184) was obtained from Dow Corning. Poly(triethylene glycol cyclopenta[2,1-b:3,4-b′]dithiophene-monoethylene glycol bithiophene) (P3gCPDT-1gT2) was synthesized according to literature [ 34 ].…”

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

“…Over the past few years, polar and hydrophilic oligo ethylene glycol (OEG) side chains modified conjugated polymers as the channel layers have been developed rapidly, [ 14–17 ] particularly for p‐type (hole transport) OECT devices with the μC* figure of merit up to ≈563 F V −1 cm −1 s −1 given by pgBTTT . [ 18–21 ] Whereas n‐type OECTs are yet much more immature than their p‐type counterparts owing to the lacking of rational n‐type design principles, although several types of n‐type polymeric structures have shown a figure of merit μC* more than 1 F V −1 cm −1 s −1 , [ 22–24 ] most of which presented unsatisfactory performance. [ 25,26 ] This unbalanced situation greatly precludes the development of the lower power consumption complementary circuits and hinders the diversity of bioelectronics applications where n‐type mixed conductors are demanded.…”

“…Over the past few years, polar and hydrophilic oligo ethylene glycol (OEG) side chains modified conjugated polymers as the channel layers have been developed rapidly, [14][15][16][17] particularly for p-type (hole transport) OECT devices with the μC* figure of merit up to ≈563 F V −1 cm −1 s −1 given by pgBTTT. [18][19][20][21] Whereas n-type OECTs are yet much more immature than…”