POS5-0602
Benzobisoxazole-Based Semicrystalline Polymer Donors for High-Gain, Low-Noise Photomultiplication-Type Organic Photodetectors
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Sumin Lee (Hanyang University)
Co-Author(s)
Abstract
Photomultiplication-type organic photodetectors (PM-OPDs) provide high sensitivity under weak illumination but typically exhibit a trade-off between photocurrent gain and dark current suppression, which limits their detectivity in practical sensing applications. In this study, benzobisoxazole-based semicrystalline polymer donors with alkylated fused-ring π-spacers were newly synthesized and implemented as donor materials in PM-OPDs. The incorporation of these π-spacers into the polymer backbone promoted a pronounced face-on molecular orientation and enhanced hole transport, thereby increasing the external quantum efficiency (EQE) and responsivity (R) while maintaining a low dark current density (Jd) . Among the synthesized polymer donors, a PUTTB with a 6-undecyl thieno[3,2-b]thiophen-2-yl (UTT) π-spacer exhibited a higher absorption coefficient, a shallower HOMO level, and reduced bimolecular recombination, which collectively facilitated efficient photomultiplication gain generation and mitigate parasitic dark-current pathways. Consequently, PUTTB-based PM-OPDs achieved an EQE of 27,280 %, a R of 117 A/W, and a specific detectivity (D*) of 3.86 × 1013 Jones at − 30 V, surpassing devices employing a conventional thiophene-based π-spacer. In addition, transient and frequency-resolved measurements revealed improved charge trapping and release dynamics, leading to superior static and dynamic response. These findings establish a molecular design strategy for semicrystalline polymer donors that enables high-gain, low-noise PM-OPDs suitable for high-performance imaging and low-light sensing platforms.
