Molecular Diffusion-Driven Graded Polymer Hole-Transport Layers Enabling Efficient and Durable Organic Photovoltaics
- 1Department of Electronic Engineering, Keimyung University, Daegu 42601, Republic of Korea
Abstract
High-performance and durable organic photovoltaics (OPVs) require interlayers that enable efficient carrier extraction and long-term stability while remaining compatible with scalable and printing-based processing. In this study, we demonstrate a molecular diffusion-driven graded polymer hole-transport layer (g-HTL) for efficient and thermally durable OPVs. The g-HTL is fabricated by water-transfer printing a thin PM6 layer onto a non-fullerene acceptor (NFA)-rich PM6:L8-BO active layer, followed by surface treatment with phosphomolybdic acid (PMA). The limited penetration of PMA produces a vertically graded p+–p–i configuration within the printed polymer layer, while preserving its laterally correlated surface morphology. OPVs incorporating a g-HTL achieve a power conversion efficiency of 17.18%, compared with 16.31% for conventional MoO3-based devices, owing to the improved carrier transport and collection. The printed PM6-based graded layer exhibits high morphological stability under thermal stress. Together with the thermally robust NFA-rich active layer, this morphologically stable g-HTL enables OPVs to retain nearly 90% of their initial efficiency after thermal aging at 85 °C for 15 days, compared with approximately 70% for MoO3-based devices. These results demonstrate that molecular diffusion engineering of printed polymer interlayers is an effective strategy for improving the efficiency and thermal durability of polymer-based photovoltaic devices.
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BibTeX
@article{baek2026molecular,
title = {{Molecular Diffusion-Driven Graded Polymer Hole-Transport Layers Enabling Efficient and Durable Organic Photovoltaics}},
author = {Seungpil Baek and Minwoo Nam},
journal = {Polymers},
year = {2026},
month = oct,
doi = {10.3390/polym18212636},
url = {https://www.mdpi.com/2073-4360/18/21/2636},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Molecular Diffusion-Driven Graded Polymer Hole-Transport Layers Enabling Efficient and Durable Organic Photovoltaics
AU - Seungpil Baek
AU - Minwoo Nam
PY - 2026
DA - 2026/10/24
JO - Polymers
DO - 10.3390/polym18212636
UR - https://www.mdpi.com/2073-4360/18/21/2636
AB - High-performance and durable organic photovoltaics (OPVs) require interlayers that enable efficient carrier extraction and long-term stability while remaining compatible with scalable and printing-based processing. In this study, we demonstrate a molecular diffusion-driven graded polymer hole-transport layer (g-HTL) for efficient and thermally durable OPVs. The g-HTL is fabricated by water-transfer printing a thin PM6 layer onto a non-fullerene acceptor (NFA)-rich PM6:L8-BO active layer, followed by surface treatment with phosphomolybdic acid (PMA). The limited penetration of PMA produces a vertically graded p+–p–i configuration within the printed polymer layer, while preserving its laterally correlated surface morphology. OPVs incorporating a g-HTL achieve a power conversion efficiency of 17.18%, compared with 16.31% for conventional MoO3-based devices, owing to the improved carrier transport and collection. The printed PM6-based graded layer exhibits high morphological stability under thermal stress. Together with the thermally robust NFA-rich active layer, this morphologically stable g-HTL enables OPVs to retain nearly 90% of their initial efficiency after thermal aging at 85 °C for 15 days, compared with approximately 70% for MoO3-based devices. These results demonstrate that molecular diffusion engineering of printed polymer interlayers is an effective strategy for improving the efficiency and thermal durability of polymer-based photovoltaic devices.
SN - 2073-4360
ER -