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

  • Green hydrogen: MXenes shows talent as catalyst for oxygen evolution
    Science Highlight
    09.09.2024
    Green hydrogen: MXenes shows talent as catalyst for oxygen evolution
    The MXene class of materials has many talents. An international team led by HZB chemist Michelle Browne has now demonstrated that MXenes, properly functionalised, are excellent catalysts for the oxygen evolution reaction in electrolytic water splitting. They are more stable and efficient than the best metal oxide catalysts currently available. The team is now extensively characterising these MXene catalysts for water splitting at the Berlin X-ray source BESSY II and Soleil Synchrotron in France.
  • Langbeinites show talents as 3D quantum spin liquids
    Science Highlight
    23.08.2024
    Langbeinites show talents as 3D quantum spin liquids
    A 3D quantum spin liquid has been discovered in the vicinity of a member of the langbeinite family. The material's specific crystalline structure and the resulting magnetic interactions induce an unusual behaviour that can be traced back to an island of liquidity. An international team has made this discovery with experiments at the ISIS neutron source and theoretical modelling on a nickel-langbeinite sample.
  • Green hydrogen: ‘Artificial leaf’ becomes better under pressure
    Science Highlight
    31.07.2024
    Green hydrogen: ‘Artificial leaf’ becomes better under pressure
    Hydrogen can be produced via the electrolytic splitting of water. One option here is the use of photoelectrodes that convert sunlight into voltage for electrolysis in so called photoelectrochemical cells (PEC cells). A research team at HZB has now shown that the efficiency of PEC cells can be significantly increased under pressure.