POS5-0802
Rational Design of High-Sensitivity Organic Photodetectors Using a Perylene Diimide Cathode Interlayer for Wireless Optical Communication
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Min Soo Kim (Chung-Ang University)
Co-Author(s)
Abstract
Organic photodetectors (OPDs) have attracted significant interest owing to their flexibility, lightweight characteristics, and solution-processability. However, undesired carrier injection and leakage currents at electrode interfaces often limit device sensitivity and operational stability. Therefore, cathode interlayer (CIL) engineering is essential for controlling interfacial energetics and improving OPD performance. In this study, a newly designed perylene diimide-based cathode interlayer, PDI3, is investigated and compared with the conventional PDINN interlayer. Owing to its rigid fluorene framework and bulky alkyl substituents, PDI3 enables controlled interfacial charge transfer and improved film formation. Ultraviolet photoelectron spectroscopy reveals that PDI3 induces a larger vacuum-level shift and increases the hole-injection barrier at the Ag cathode interface. Atomic force microscopy further demonstrates a smoother and more homogeneous morphology, indicating improved interfacial uniformity and reduced leakage pathways. As a result, PDI3-based OPDs exhibit a significantly reduced dark current density of 3.63 × 10⁻⁹ A cm⁻² while maintaining comparable photoresponse characteristics. In addition, enhanced shunt resistance and suppressed charge recombination contribute to improved device sensitivity and signal stability. The PDI3-modified device achieves a detectivity of 1.52 × 10¹³ Jones and demonstrates stable operation under optical pulse measurements and wireless optical communication tests. These findings highlight the importance of interfacial energetics and morphology control through rational cathode interlayer design and provide an effective strategy for developing highly sensitive organic photodetectors for future optical sensing and communication applications.
