Researchers from Kaunas University of Technology developed a novel approach for selective layer formation in perovskite solar cells
Perovskite-based solar cells are emerging photovoltaics devices that are been compared for efficiency with well-established solar technologies used in solar panels. Now a team of researchers from Kaunas University of Technology (KTU) and Helmholtz Zentrum Berlin (HZB) developed a new approach to form selective contact layers that can be compatible for depositing perovskite layers on various substrates. According to the researchers, the new approach facilitates mass production of perovskite solar cells.
Spin-coating and vapor deposition are the two main methods that are currently used for the formation of layers in perovskite solar cells. Spin-coating includes dripping of liquid solution on spinning surfaces and during this process large quantities of the material is wasted. Vapor deposition relies on high temperatures and complex vacuum technologies and not all molecules are suitable for evaporating. The KTU team synthesized a molecule that assembles itself into a monolayer that can evenly cover any oxide surface such as textured surfaces of the silicon solar cells that are used in tandem architectures. According to Ernestas Kasparavicius, PhD student at KTU Faculty of Chemical Technology, the formation of the monolayer through dipping the surface into the solution makes the method cheaper than current alternatives. He also stated that the synthesis of the compound is a shorter process as compared to that of the polymer that is usually used in production of perovskite solar cells.
To test the synthesized material, the team successfully used this new material as a hole transporting layer in perovskite solar cells. The team found that extremely low material consumption is achieved using self-assembling monolayer technique. Moreover, the element’s power conversion efficiency was around 18 %, which according to the researchers is exceptionally high for a new technology. Additives are not needed to improve the performance of the cells when self-assembling monolayer is used as a hole transporting layer in perovskite cells. This in turn improves the life span of the elements. The research was published in the journal Advanced Energy Materials on November 15, 2018.