Unravelling Kinetic Loss Mechanisms in All-Polymer Solar Cells

Shahidul Alam^a^,^b, Wejdan Althobaiti^b, Safakath Karuthedath^c, Christopher E. Petoukhoff^b, Amr Dahman^b, Khawla Alkhezaim^b, Oleksandr Matiash^b, José P. Jurado^b, Mariia Ferree^a, Ning Su^d, Jacob Blaskovits^e, Denis Andrienko^e, Vladimir Dyakonov^f, Andreas Sperlich^f, Vojtech Nádaždy^g, Tobin J. Marks^d, Antonio Facchetti^d^,^h, Frédéric Laquai^a^,^b

^aChair of Physical Chemistry and Spectroscopy of Energy Materials, Department of Chemistry, Ludwig Maximilians University Munich, Butenandtstraße 11 (E), D-81377 Munich, Germany

^bKing Abdullah University of Science and Technology (KAUST), KAUST Solar Platform (KSP), Physical Sciences and Engineering Division (PSE), Material Science and Engineering Program (MSE), Thuwal 23955-6900, Kingdom of Saudi Arabia

^cInstitute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055 China

^dDepartment of Chemistry, Center for Light Energy-Activated Redox Processes, and the Materials Re-search Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (USA)

^eMax Planck Institute for Polymer Research (MPIP), Ackermannweg 10, D-55128 Mainz, Germany

^fExperimental Physics 6, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany

^gInstitute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava, Slovak Republic

^hSchool of Materials Science and Engineering, Georgia Institute of Technology; Atlanta, GA 30332, USA

Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV26)

Uppsala, Sweden, 2026 May 18th - 20th

Organizers: Gerrit Boschloo, Ellen Moons, Feng Gao and Anders Hagfeldt

Oral, Shahidul Alam, presentation 117
DOI: https://doi.org/10.29363/nanoge.hopv.2026.117
Publication date: 11th March 2026

All-polymer solar cells offer potential advantages in mechanical robustness and morphological stability, yet they remain less efficient than state-of-the-art small-molecule non-fullerene acceptor–based organic solar cells. In this work, we investigate the efficiency-limiting processes in all-polymer bulk heterojunction devices based on the donor polymers PBDB-T and PBDB-T-2F (PM6) blended with the polymer acceptors PYN-BDT and PYN-BDTF. Owing to π-extended naphthalene units, the acceptor polymers exhibit strong absorption extending to approximately 900 nm. A combination of steady-state spectroscopy and time-resolved techniques—including transient absorption, time-resolved photoluminescence, photoluminescence-detected magnetic resonance, and time-delayed collection field measurements—enables a quantitative analysis of charge-generation and loss processes. Kinetic parameters and process yields derived from pulsed-laser spectroscopy reproduce the measured current–voltage characteristics, confirming the consistency of the approach. The results show that moderate fill factors arise from non-geminate recombination competing with charge extraction and from field-dependent charge generation, with the relative importance of these processes depending on the polymer acceptor. The methodology provides a general framework for quantifying loss mechanisms in bulk heterojunction organic solar cells.

nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.

MATSUS

Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.

International Conference on Hybrid and Organic Photovoltaics

International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.

Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics

The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.

International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics

The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.