Strategically tailoring ethylene glycol side chains with bridged-carbonyl ester in polythiophene-based organic electrochemical transistors for bioelectronics

Conjugated Radical Polymer-Based Organic Electrochemical Transistors for Biosensing Devices

“…40 Transient characteristics (I DS −time) were evaluated in an aqueous 0.1 M NaCl solution using a pulsed gate voltage (V GS ) of −0.6 V, with a pulse width of 6 × 10 −8 s and a pulse period of 1.4 × 10 −7 s, while V DS was maintained at −0.6 V (Figure 5). Thin films loaded with 25 wt % CRP show consistent "spike and recovery" behavior, 35,36,41 alongside excellent retention of "spike and recovery" current changes (ΔI), with the values remaining constant after 500 cycles (Figure 5a,b). Furthermore, it exhibits a superior ΔI of 1.26 μA, surpassing that of the pristine P3MEET by 1.5 times (ΔI of 0.84 μA).…”

“…This suggests that the 25 wt % blending exhibits lower current leakage and a smaller decline in total impedance compared to pristine P3MEET. 34,35 Furthermore, the 25 wt % blending shows a smoother valley in the magnitude plot (black curve) and a lower phase angle observed within the medium frequency range, indicating higher ionic permeability and transportability inside the active channel, compared to pristine P3MEET. 34 However, overloading CRP leads to inferior capacitive behavior and reduced ability for ionic dopant infiltration, as indicated by low Bode phase φ values at lower frequency ranges and high phase angles observed within medium frequency ranges (Figure S8).…”

“…Bode phase angle plots (dark-red curves) reveal that both pristine P3MEET and P3MEET blended with BTMP-EDOT at 25 wt % loadings exhibit pseudocapacitive behavior at lower frequencies (φ near −45°) and resistive behavior at higher frequencies (φ near 0°). 34,35 Notably, in the lower frequency range, the 25 wt % blending (φ near −45°) demonstrates superior capacitive behavior compared to pristine P3MEET (with φ near −40°). This suggests that the 25 wt % blending exhibits lower current leakage and a smaller decline in total impedance compared to pristine P3MEET.…”

“…The V Th and V GS correspond to the threshold voltage and gate voltage at maximum g m , respectively. 35,39 The incorporation of BTMP-EDOT CRP into the P3MEET active channel layer results in an increase in μC* from 1.27 F V −1 cm −1 s −1 (for pristine P3MEET) to 27.34 F V −1 cm −1 s −1 at 25 wt % CRP loading. However, a rapid decline in μC* is observed upon further increasing the loading of the radical polymer into the blend (Figure S9b,c).…”