Scientists realize perovskite-based phase heterojunction solar cells

• Over the past few decades, engineers as well as material scientists have produced progressively innovative as well as effective solar innovations. Some of these innovations are based upon photovoltaics with a supposed heterojunction framework, which involves the combination of two materials with distinct optoelectronic homes.

Researchers at Technische Universität Dresden have recently realized a different type of solar cells, referred to as phase heterojunction (PHJ) solar cells. These cells, presented in a paper released in Nature Energy, were fabricated making use of two polymorphs (i.e., structural types) of the same product, the perovskite CsPbI3, rather than 2 completely various semiconductors.

" The awareness of a PHJ requires the ability to fabricate 2 various phases of the exact same perovskite structure on top of each other," Yana Vaynzof, lead author of the paper, told TechXplore. "While the manufacture of- phase CsPbI3 perovskite by solution-processing is well established in the literature, we required to create a technique to deposit a- phase perovskite without liquifying the underlying- phase layer, so we decided to use thermal evaporation for this purpose."

In one of their previous research studies, Vaynzof and her team designed a strategy to evaporate- phase CsPbI3 perovskites by heating them. This approach proved to be crucial for the experimental awareness of their new PHJ solar cells.

" PHJs exploit the fact that the specific arrangement of atoms/molecules in crystalline products (i.e., the product's phase) may bring about the emergence of various properties," Vaynzof described. "This is undoubtedly the situation with as well as- phase CsPbI3 perovskites, since phase leads to a larger bandgap than the phase. Based upon their different residential or commercial properties, interfacing both phases in a heterojunction can be used to develop an useful energised landscape for the photogenerated charges in the photovoltaic tool, and by doing so enhance the photovoltaic performance."

To create their PHJ solar cell, Vaynzof and her trainees had to deposit the two material phases so that they were one on top of the other. This was accomplished making use of a series of corresponding deposition techniques.

" We selected to deposit all-time low- phase by solution-processing, as well as the top- phase by thermal evaporation, which guaranteed the formation of a sharp interface between both layers and works with processing at fairly low temperature levels," Vaynzof claimed. "Ours is the initial demo of the phase heterojunction as a novel concept for photovoltaics."

The recent job by this team of scientists can open fascinating possibilities for the creation of new PHJ photovoltaic or pv innovations, which differ substantially from those readily available today. As numerous semiconductor materials exhibit polymorphism (i.e., the ability to exist in different crystalline phases), the same approach utilized to create this PHJ solar cell could be related to various other perovskites and other semiconducting materials with various homes.

In their next researches, Vaynzof and her team will proceed working on cutting-edge solar power services. As an example, they currently intend to create strategies that would enable them to control the phases of perovskite products, as this could boost their PHJ solar cell design further.

" These strategies will permit us to explore various phase heterojunction configurations for different perovskite make-ups and integrate them right into various photovoltaic or pv tool designs," Vaynzof included. "Importantly, we aim to utilize only thermal evaporation as the deposition method in order to enable the manufacture of multi-layered structures without the constraints that arise from using solvents in solution handling. Taking into consideration that thermal evaporation is an extremely scalable, industrially relevant method, this will certainly assist in the future assimilation of phase heterojunction into industrial applications."