POS5-0832
Over 20.6% Efficiency Organic Photovoltaics Enabled by Co-Assembled Monolayer Interface Engineering
Topic
S5. Polymers for Electronics and Photonics
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Changhun Yu (KAIST)
Co-Author(s)
Abstract
Intrinsically high-efficiency organic photovoltaics (OPVs) are emerging as next-generation energy harvesters, where optimizing the hole transport layer (HTL) via phosphonic acid-based self-assembled monolayers (SAMs) is crucial to minimize interfacial energy barriers. However, conventional single-component SAMs frequently suffer from molecular aggregation, severe pinhole formation and phase separation, introducing localized energetic disorders that degrade both charge extraction and active layer morphology. Achieving simultaneous morphological uniformity and precise work function modulation has remained a significant challenge with conventional single-component SAMs. In this study, we introduce a co-SAM strategy by co-depositing Br-2PACz with a molecular modulator (BPA), which synergistically achieves both requirements within a single interfacial architecture. The incorporation of BPA promotes a homogeneous Br-2PACz arrangement, effectively filling pinholes and eliminating localized charge traps, which in turn facilitates efficient charge transport and induces a preferred face-on orientation in the active layer, yielding a state-of-the-art PCE of 20.61%. These findings demonstrate that co-SAM engineering is a practical and effective HTL strategy, offering a straightforward path toward further advancing OPV efficiencies.
