Improving Ideality of P-Type Organic Field-Effect Transistors via Preventing Undesired Minority Carrier Injection

摘要

Electron injection plays a crucial role in arousing the double-slope characteristics for p-type organic field-effect transistors (OFETs) with narrow-bandgap organic semiconductors (OSCs). This issue will not only result in the misrepresentation of OFET performance but also may cause device instability, hence impeding their further development in real-world applications. A facile and highly efficient approach is developed to circumvent this issue by implementing modification on the electrode/organic semiconductor interface. An ultrathin layer of wide-bandgap OSC with suitable energy levels is introduced to block the undesirable electron injection. By this means, typical double-slope behaviors and bias stress stability in the p-type OFETs can be significantly improved. Using 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene-based OFETs the double-slope behaviors of as-fabricated devices are effectively converted to near-ideal behaviors after modification, leading to a dramatic improvement of average reliability from 65.11% to 91.76%. Furthermore, the positive drift of transfer curves under prolonged bias stress is also successfully suppressed. This strategy demonstrates good universality and can provide a new guideline for the fabrication of OFETs with ideal behaviors.