Balanced Intra- and Interchain Exciton Delocalization Enables Efficient All-Polymer Solar Cells
Abstract
Polymerized Y-type nonfullerene acceptors (PY-NFAs) have shown great promise for efficient and stable organic solar cells (OSCs), yet their excited-state dynamics and structure-photophysics-performance relationships remain unclear. Here, we investigate a series of PY-NFAs and distinguish between intrachain excitons (intra-Ex) and interchain excitons (inter-Ex) formed in the solid state using cryogenic transient absorption (TA) spectroscopy at 100 K. We identify the emergence of trapped intra-Ex in the PY-NFA films from approximately 100 ps onwards after photoexcitation. By comparing this low-temperature TA signal among different PY-NFA films, we uncover a strong correlation between the trapped intra-Ex signature and the performance of these PY-NFAs in donor-acceptor blend OSC devices. This correlation indicates that the low-temperature TA response provides a quantitative measure of structural disorder in the PY-NFA aggregates and in the corresponding donor-acceptor blends. Correlating these spectroscopic results with molecular packing and morphological data, we reveal that high-performance PY-NFAs simultaneously exhibit (1) extended backbone conjugation and large intrachain exciton bandwidths and (2) uniform, oriented interchain packing despite moderately increased - stacking distances. These findings provide new design rules for PY-NFAs and offer deeper insight into how structural disorder and exciton dynamics govern OSC performance.
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BibTeX
@article{guo2026balanced,
title = {{Balanced Intra- and Interchain Exciton Delocalization Enables Efficient All-Polymer Solar Cells}},
author = {Yu Guo and Yuang Fu and Xianzhao Liu and Youcai Liang and Fei Huang and Xinhui Lu and Philip C.Y. Chow},
journal = {PRX Energy},
year = {2026},
month = jun,
doi = {10.1103/fls9-jc34},
url = {https://hal.science/hal-05793505v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Balanced Intra- and Interchain Exciton Delocalization Enables Efficient All-Polymer Solar Cells
AU - Yu Guo
AU - Yuang Fu
AU - Xianzhao Liu
AU - Youcai Liang
AU - Fei Huang
AU - Xinhui Lu
AU - Philip C.Y. Chow
PY - 2026
DA - 2026/06/08
JO - PRX Energy
DO - 10.1103/fls9-jc34
UR - https://hal.science/hal-05793505v1
AB - Polymerized Y-type nonfullerene acceptors (PY-NFAs) have shown great promise for efficient and stable organic solar cells (OSCs), yet their excited-state dynamics and structure-photophysics-performance relationships remain unclear. Here, we investigate a series of PY-NFAs and distinguish between intrachain excitons (intra-Ex) and interchain excitons (inter-Ex) formed in the solid state using cryogenic transient absorption (TA) spectroscopy at 100 K. We identify the emergence of trapped intra-Ex in the PY-NFA films from approximately 100 ps onwards after photoexcitation. By comparing this low-temperature TA signal among different PY-NFA films, we uncover a strong correlation between the trapped intra-Ex signature and the performance of these PY-NFAs in donor-acceptor blend OSC devices. This correlation indicates that the low-temperature TA response provides a quantitative measure of structural disorder in the PY-NFA aggregates and in the corresponding donor-acceptor blends. Correlating these spectroscopic results with molecular packing and morphological data, we reveal that high-performance PY-NFAs simultaneously exhibit (1) extended backbone conjugation and large intrachain exciton bandwidths and (2) uniform, oriented interchain packing despite moderately increased - stacking distances. These findings provide new design rules for PY-NFAs and offer deeper insight into how structural disorder and exciton dynamics govern OSC performance.
SN - 2768-5608
ER -