Tuning Interfacial Properties by Spontaneously Generated Organic Interlayers in Top‐Contact‐Structured Organic Transistors

Abstract

Controlling the interfacial properties between the electrode and active layer in organic field‐effect transistors (OFETs) can significantly affect their contact properties, resulting in improvements in device performance. However, it is difficult to apply to top‐contact‐structured OFETs (one of the most useful device structures) because of serious damage to the organic active layer by exposing solvent. Here, a spontaneously controlled approach is explored for optimizing the interface between the top‐contacted source/drain electrode and the polymer active layer to improve the contact resistance (RC). To achieve this goal, a small amount of interface‐functionalizing species is blended with the p‐type polymer semiconductor and functionalized at the interface region at once through a thermal process. The RC values dramatically decrease after introduction of the interfacial functionalization to 15.9 kΩ cm, compared to the 113.4 kΩ cm for the pristine case. In addition, the average field‐effect mobilities of the OFET devices increase more than three times, to a maximum value of 0.25 cm2 V−1 s−1 compared to the pristine case (0.041 cm2 V−1 s−1), and the threshold voltages also converge to zero. This study overcomes all the shortcomings observed in the existing results related to controlling the interface of top‐contact OFETs by solving the discomfort of the interface optimization process.

Metal–Organic Framework as a Functional Analyte Channel of Organic-Transistor-Based Air Pollution Sensors

“…Because the P3HT/ZIF-8 hybrid thin films exhibited identical UV–vis absorption spectra (Figure S1), the increased hole mobility and OTFT performance are attributed to the electrical conductivity of the carbonized ZIF-8s rather than to structural development of P3HT crystals or charge-transfer doping of P3HT chains from carbonized ZIF-8s (Figure ). , The carbonized ZIF-8 clusters are conductive, , which can reduce the effective channel length between the source and drain electrodes (i.e., the charge bridge effect) . The reduced channel length can increase the nominal hole mobility evaluated from the transfer curves.…”

Improving Charge Injection at Gold/Conjugated Polymer Contacts by Polymer Insulator‐Assisted Annealing for Transistors

“…[ 22–25 ] Several methods have been proposed to reduce the contact resistance and improve charge injection at metal/organic interface, such as contact doping, introducing a charge injection layer, or forming an abrupt damage‐free metal/semiconductor interface by transferred electrodes. [ 2,5,24–30 ] However, these methods require additional and complicated processes, which increase the difficulty of device fabrication and some of them also damage organic films. [ 27 ] Actually, due to the dynamic impact of metal deposition process, the disordered metal/organic interface may be a thermodynamically non‐equilibrium state, which could be potentially reformed to construct a more ordered and stable structure spontaneously, thereby eliminating the adverse effects of metal deposition.…”

“…[22][23][24][25] Several methods have been proposed to reduce the contact resistance and improve charge injection at metal/organic interface, such as contact doping, introducing a charge injection layer, or forming an abrupt damage-free metal/semiconductor interface by transferred electrodes. [2,5,[24][25][26][27][28][29][30] However, these methods require additional and complicated processes, which increase the difficulty of device fabrication and some of them also…”

Exploration on Solvatochromic Sensing Probe of Phenol Blue for L‐Lactic Acid Detection: Effective Strategy to Obtain Reliable Capacitive Sensor

“…Organic active materials are gaining extensive attention in various fields of flexible wearable electronic devices, [1][2][3] including radio-frequency identification tags, [4,5] flexible displays, [6,7] and physical/chemical sensors owing to their advantages such as mechanical flexibility, [8][9][10] easy molecular design, [11][12][13] and solution processing. [14][15][16] Among various application fields, organic physical and chemical sensors are core elements of wearable devices for collecting information of biomechanical and physiological data to diagnose a human disease or monitoring exercise status. A representative indicator for monitoring health status is L-lactic acid (LA) concentration in blood or sweat.…”