Direct Visualization of Carrier Motion in DPP-TTT/C₃N₅ Blended Organic Thin-Film Transistors by Optical Second-Harmonic Generation

The study of how charge carriers move within organic materials is attracting significant attention for its relevance to a variety of applications in the field of electronics such as in the development of organic thin-film transistors, organic light-emitting devices, and organic photoconductors. There is growing excitement among researchers to exploit the unique characteristics of organic materials to push the boundaries of technology in organic electronics and optoelectronics. This research provides an in-depth examination of charge transport dynamics in an innovative DPP-TTT/C 3 N 5 blend-based organic field-effect transistor (OFET), employing time-resolved second harmonic generation (TR-SHG) as the main method of investigation. The integration of C 3 N 5 -conducting nanoflakes into the DPP-TTT polymer matrix marks a significant advancement in the design of organic semiconductors aimed at enhancing charge mobility and overall device performance. Through the application of TR-SHG, a noninvasive optical technique that probes the electric field-induced changes within the material, we have been able to directly visualize and quantify the dynamic behavior of charge carriers within the OFET structure. Our findings reveal that the inclusion of C 3 N 5 nanoflakes not only improves the structural ordering within the DPP-TTT matrix but also significantly enhances the charge carrier mobility and fills the trap state using C 3 N 5 Nanosheets. This enhancement is attributed to the establishment of more efficient pathways for charge transport, reducing trap states, facilitated by the ordered lamellar packing induced by C 3 N 5 integration. The TR-SHG technique, with its unique ability to capture the motion of charge carriers in real time, has provided invaluable insights into the mechanisms underlying the improved performance of the DPP-TTT/C 3 N 5 blend-based OFETs. This study not only demonstrates the potential of TR-SHG as a powerful tool for investigating the dynamic aspects of charge transport in organic semiconductors but also highlights the promising future of DPP-TTT/C 3 N 5 blends in the development of high-performance organic electronic devices.