Precisely Patterned Channels in a Vertical Organic Electrochemical Transistor with a Diazirine Photo‐Crosslinker

Abstract Organic electrochemical transistors (OECTs) rely on both efficient ionic doping/de‐doping process and carrier transport in the mixed ionic‐electronic channel under the modulation of gate bias. Moreover, channels that hold photopatterning capability are highly desired to minimize parasitic capacitance and simplify the fabrication process/cost. However, yielding photo‐patternable channels with both precise/robust patterning capability and controllable ionic‐electronic coupling is still challenging. Herein, double‐end trifluoromethyl diazirines (DtFDA) with different chain lengths are introduced in the OECT channel to act as both photo‐crosslinker and medium to regulate ionic‐electronic transport. Specifically, high‐resolution patterns with a minimum line width/gap of 2 μm are realized in p(g2T‐T) or Homo‐gDPP based channels by introducing DtFDA. Maximum transconductances of 68.6 mS and 81.6 mS, current on/off ratio of 10 6 and 10 7 (under a drain voltage of only ±0.1 V), are achieved in p‐ and n‐type vertical OECTs (vOECTs), respectively, along with current densities exceeding 1 kA cm −2 and good cycling stability of more than 100,000 cycles (2000 seconds). This work provides a new and facile strategy for the fabrication of vOECT channels with high resolution and high performance via the introduction of a simple and efficient crosslinker.