Disordered Semiconductors

The semiconductor industry has long been dominated by inorganic materials, but organic semiconductors offer new possibilities with their customizable electronic properties, mechanical flexibility, and environmentally friendly nature. These materials enable applications beyond the reach of traditional semiconductors, paving the way for sustainable electronics and spintronics. However, major challenges in organic semiconductor technologies include their inherent disorder and stability, both of which constrain performance and scalability. Addressing these issues requires an interdisciplinary approach that combines advanced fabrication techniques with novel characterization methods.

This CReA focuses on bringing order to disordered organic semiconductors by leveraging epitaxial growth technique. Additionally, it will use advanced spectroscopic tools to gain deeper understanding into the remaining unresolved questions. Key objectives include:

• Developing epitaxial organic photoactive layers using molecular beam epitaxy (MBE) to control disorder-related limitations in organic solar cells.
• Device physics of organic and hybrid solar cells.
• Fundamental electrical, spectroscopic and structural studies of molecular electronic materials with numerical modelling and device studies, with the aim of optimizing the performance and stability of single junction and tandem solar cells based on molecular and hybrid materials.
• Probing dark spin states, to understand spin-transport, spin-generation and spin-detection at room temperature to explore their potential for spintronics.
• Advancing experimental and modeling tools to clarify the fundamental structure-property relationships in organic semiconductors.

We are interested in advancing scientific understanding of the charge and spin transport as well as the photophysics of organic semiconductors and low-temperature processible hybrid organic-inorganic semiconductors. By bridging the gap between organic and inorganic semiconductor research, this work opens new possibilities for high-performance optoelectronic and spintronic devices. The ability to fabricate highly ordered organic semiconductors could lead to more efficient solar cells, and novel hybrid materials. Furthermore, gaining insights into spin properties at room temperature brings us closer to practical spintronic applications. Ultimately, this research contributes to the development of transformative, sustainable technologies that address global challenges in energy (mitigation potential of solar photovoltaic technology) and information processing.

• Leibniz: Sinfonia
• EU MSCA: OPVStability
• Pushing the FF of Non-Fullerene Acceptors Based Solar Cells Above 80%: Relating Order to Reduced Recombination to Device Performance (Fabulous II)

2025

• Understanding the fill-factor limit of organic solar cells
  Authors: Huotian Zhang, Jun Yuan, Tong Wang, Nurlan Tokmoldin, Rokas Jasiunas, Yiting Liu, Manasi Pranav, Yuxuan Li, Xiaolei Zhang, Vidmantas Gulbinas, Safa Shoaee, Yingping Zou, Veaceslav Coropceanu, Artem A Bakulin, Dieter Neher, Thomas Kirchartz, Feng Gao
  Source: arXiv preprint arXiv.2507.22217
  DOI: https://doi.org/10.48550/arXiv.2507.22217
   
• Discerning Performance Bottlenecks of State‐of‐the‐Art Narrow Bandgap Organic Solar Cells
  Authors: Atul Shukla, Manasi Pranav, Guorui He, J Terence Blaskovits, Davide Mascione, Yonglin Cao, Yufei Gong, Drew B Riley, Julian A Steele, Eduardo Solano, Alexander Ehm, Mohammad Saeed Shadabroo, Ardalan Armin, Safa Shoaee, Dietrich RT Zahn, Yongfang Li, Lei Meng, Felix Lang, Denis Andrienko, Dieter Neher
  Source: Advanced Energy Materials, 2502398
  DOI: https://doi.org/10.1002/aenm.202502398
   
• Triplet Excitons Reconcile Charge Generation and Recombination in Low-Offset Organic Solar Cells: Efficiency Limits from a 5-State Model
  Authors: JL Langentepe-Kong, M Pranav, S Shoaee, D Neher
  Source: arXiv preprint arXiv:2505.15603
  DOI: https://doi.org/10.48550/arXiv.2505.15603
   
• Toward understanding the built-in field in perovskite solar cells through layer-by-layer surface photovoltage measurements
  Authors: Emilio Gutierrez-Partida, Marin Rusu, Fengshuo Zu, Meysam Raoufi, Jonas Diekmann, Nurlan Tokmoldin, Jonathan Warby, Dorothee Menzel, Felix Lang, Sahil Shah, Safa Shoaee, Lars Korte, Thomas Unold, Norbert Koch, Thomas Kirchartz, Dieter Neher, Martin Stolterfoht
  Source: ACS Appl. Mater. Interfaces 2025, 17, 7, 11176–11186
  DOI: https://doi.org/10.1021/acsami.4c14194

2024

• Contemporary Impedance Analyses of Archetypical PM6: Y6 Bulk‐Heterojunction Blend
  Authors: N. Tokmoldin, C. Deibel, D. Neher, S. Shoaee
  Source: Adv. Energy Mater., 14, 2401130 (2024)
  DOI: 10.1002/aenm.202401130
   
• Key factors behind the superior performance of polymer-based NFA blends
  Authors: E. Sağlamkaya, M. S. Shadabroo, N. Tokmoldin, T. M. Melody, B. Sun, O. Alqahtani, A. Patterson, B. A. Collins, D. Neher, S. Shoaee
  Source: Mater. Horiz., 11, 5304-5312 (2024)
  DOI: 10.1039/D4MH00747F

2023