POS5-1226
Optimizing Hole-Transport Interfaces in Infrared Photodetectors Using Phosphonic Acid-Modified Conjugated Polymers
Topic
S5. Polymers for Electronics and Photonics
When and Where
Oct 1, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Jinkee HONG
Ki Su KIM
Presenter(s)
Ji Hyeon Lee (Gwangju Institute of Science and Technology; Korea Institute of Science and Technology)
Co-Author(s)
Abstract
Conjugated polymers (CPs) hold great potential as hole-transporting layers (HTLs) in advanced optoelectronics. However, traditional CPs with alkyl side chains often exhibit poor interfacial interactions, causing increased charge recombination. To overcome this, we developed a CP-based HTL covalently modified with phosphonic acid groups (PA15). This material was synthesized by copolymerizing a phosphonate ester monomer followed by hydrolysis. When tested in near-infrared organic photodetectors (λ=808 nm) and short-wave infrared lead sulfide colloidal quantum dot photodetectors (λ=1550 nm), the PA15-based devices delivered specific detectivities (D*) of 1.15×1013 and 7.72 ×1012 cm Hz0.5 W-1, respectively—orders of magnitude higher than control devices. Structural studies revealed that while phosphonate esters disrupt beneficial face-on stacking, converting them to phosphonic acid mitigates this issue. Furthermore, the phosphonic acid groups promote strong interlayer bonding (via P–OH) and intermolecular coupling (via a P–O–π effect). This dual improvement significantly boosts hole extraction and transport, highlighting this molecular tuning approach as a highly effective strategy for next-generation HTLs.
