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Materials for Highly Efficient Tandem Solar Cells

Technology Overview

Increasing the efficiency of solar cells is the subject of research by many scientific groups around the world. This can be achieved by using tandem technology, where two (or more) light-absorbing layers are used, and thus the losses are reduced.

Realisation of the highly efficient tandems requires simple and robust interconnection layer, which should bridge two different technologies, and thus, be compatible with both of them. This role goes to the hole-transporting material, where typically organic materials are used.

This technology presents simple organic molecules synthesised by the research team, which self-assemble into a molecular-thick electrode layer, providing a simple way to realise highly efficient tandem solar cells with perovskite absorber layer. The efficiency of tandem Si/perovskite solar cells developed by the international team is 29.15%. This is a world record for this type of element. The technology was created and developed in collaboration with a German energy materials research institute.

Technology Features, Specifications and Advantages

This technology relates to uniformly formed hole-conducting material layers on transparent conductive oxides (TCOs) with a minimised layer thickness. The material is designed to self-assemble on different surfaces. Formed layer is also tolerant against perovskite processing and able to conformally cover rough or textures surfaces, such as CIGS or textured silicon bottom cells.

The patented self-organising materials consist of the hole-transporting fragment, which is connected through the linker to the anchoring group. Such design ensures combination of the suitable electrical properties with the high affinity to the substrates. Variety of different techniques can be used for the layer formation, including dip-coating, spin-coating, blade-coating, etc.

This technology also features significantly reduced material consumption, minimal parasitic absorption, and avoidance of additional doping procedures.

Potential Applications

This technology enables formation and fabrication of the highly efficient tandem solar cells, which would further reduce costs of the solar electricity. The materials are compatible with different bottom cells, such as CIGS, Si, tin-lead perovskites. Furthermore, the scope of the materials is not limited to the tandem devices, but could be used instead of conventional organic hole-transporting materials for different electronic technologies (e.g. OLED, OFET, photoreceptors, etc.)

Customer Benefit

The technology enables highly efficient tandem perovskite solar cells.

  • It enables good coverage on any oxide surfaces, even rough surfaces of CIGS solar cells, or textured Si solar cells.
  • It is also suitable for large-area coating.
  • Materials are synthesised using simple methods, making them economically attractive.
  • The materials are simple and reliable, making them easy to apply in industry.
Contact Person

Odeta Brigaitytė


Kaunas University of Technology

Technology Category

  • Chemicals
  • Coatings/Paints, Composites
  • Electronics
  • Energy
  • Solar
  • Materials

Technology Readiness Level


Solar cells, organic molecules, solar energy, chemistry