Molecules that self-assemble into monolayers for efficient perovskite solar cells

The molecule organises itself on the electrode surface until a dense, uniform monolayer is formed.

The molecule organises itself on the electrode surface until a dense, uniform monolayer is formed. © Saule Magomedoviene / HZB

“Self‐Assembled Hole Transporting Monolayer for Highly Efficient Perovskite Solar Cells”. Cover of current issue of Advanced Energy Materials.

“Self‐Assembled Hole Transporting Monolayer for Highly Efficient Perovskite Solar Cells”. Cover of current issue of Advanced Energy Materials. © Wiley/VCH

A team at the HZB has discovered a new method for producing efficient contact layers in perovskite solar cells. It is based on molecules that organise themselves into a monolayer. The study was published in Advanced Energy Materials and appeared on the front cover of the journal.

In recent years, solar cells based on metal halide perovskites have achieved an exceptional increase in efficiency. These materials promise cost-effective and flexible solar cells, and can be combined with conventional PV materials such as silicon to form particularly efficient tandem solar cells. An important step towards mass production is the development of efficient electrical contact layers that would allow deposition of perovskite layers on various substrates.

Molecules form monolayer

Now the HZB Young Investigator Group headed by physicist Dr. Steve Albrecht, in collaboration with former DAAD exchange student Artiom Magomedov from Kaunas University of Technology (KTU) in Lithuania, has synthesized a novel molecule that self-assembles into a monolayer (SAM). The team successfully used this new material as a hole-conducting layer in perovskite solar cells. The molecule is carbazole-based and bonds to the oxide of the transparent electrode via a phosphonic acid anchoring group. Due to the anchoring fragment, this molecule organises itself on the electrode surface until a dense, uniform monolayer is formed. The ultra-thin layer exhibits no optical losses and, thanks to its self-organising property, could conformally cover any surface – including textured silicon in tandem solar-cell architectures.

Adaption possible

Extremely low material consumption is achieved with this technique, and the chemical structure of the SAMs can be adapted to the desired application. Thus, SAMs could also serve as a model system for future investigations of the properties of perovskite interfaces and growth.

New generation to be developed at HySPRINT Lab

The work took place at the HySPRINT laboratory of the HZB where Albrecht's group is now conducting research on a new generation of self-assembling molecules, which already enable solar cells with efficiencies of over 21 %.

Patent application filed

Since this approach to perovskite solar cells has never been considered before and can potentially play a role in industrial processes, the HZB and KTU teams have filed a patent application on the molecule and its use. As the scientific interest for this new contact material class is enormous, the journal has displayed an illustration from the paper on the front cover of the current issue.

Published in Advanced Energy Materials 2018: “Self‐Assembled Hole Transporting Monolayer for Highly Efficient Perovskite Solar Cells”. Artiom Magomedov, Amran Al‐Ashouri, Ernestas Kasparavičius, Simona Strazdaite, Gediminas Niaura, Marko Jošt, Tadas Malinauskas, Steve Albrecht and Vytautas Getautis.

Doi: 10.1002/aenm.201870139

Autor: Amran Al Ashouri, PhD student and shared first author of the publication

  • Copy link

You might also be interested in

  • Rutger Schlatmann re-elected as ETIP PV Chair
    News
    24.10.2024
    Rutger Schlatmann re-elected as ETIP PV Chair
    The European Technology and Innovation Platform for Photovoltaics (ETIP PV) was created by the European Commission in order to promote photovoltaic technologies and industries in Europe. Now, the ETIP PV Steering Committee elected a new Chair, as well as two Vice-Chairs for the term 2024 – 2026. Rutger Schlatmann, head of the division Solar Energy at the HZB, and professor at HTW Berlin, was re-elected as the ETIP PV Chair.
  • Perovskite solar cells: TEAM PV develops reproducibility and comparability
    News
    22.10.2024
    Perovskite solar cells: TEAM PV develops reproducibility and comparability
    Ten teams at Helmholtz-Zentrum Berlin are building a long-term international alliance to converge practices and develop reproducibility and comparability in perovskite materials. The TEAM PV project is funded by the Federal Ministry of Education and Research (BMBF), Germany.
  • Photovoltaic living lab reaches the 100 Megawatt-hour mark
    News
    27.09.2024
    Photovoltaic living lab reaches the 100 Megawatt-hour mark
    About three years ago, the living laboratory at HZB went into operation. Since then, the photovoltaic facade has been generating electricity from sunlight. On September 27, 2024, it reached the milestone of 100 megawatt-hours.