Proceedings of nanoGe International Conference on Perovskite Solar Cells, Photonics and Optoelectronics (NIPHO19)
DOI: https://doi.org/10.29363/nanoge.nipho.2019.059
Publication date: 21st November 2018
Tandem solar cells, which combine the materials perovskite and silicon, are promising candidates for power conversion efficiencies over 30%. To take full advantage of the tandem structure there must be an optimization of light management at the interfaces of the device. For silicon solar cells, KOH etched random pyramid structures are commonly used as light management texture. However, conventional pyramids cannot be applied on a silicon bottom cell in combination with spin coating as perovskite deposition method due to their structure size.
This research aims at developing tailor-made light management nano-structures for interfaces in perovskite-silicon tandem solar cells which are compatible with spin coating of perovskite while at the same time showing low reflection losses as well as good electronic properties.
In this work a hexagonal three dimensional sinusoidal nano-structure with a period of 750nm and an aspect ratio of approximately 0.5 was developed. The structure was produced by the replication process nanoimprint lithography and subsequently transferred into crystalline silicon via reactive ion etching.
The reflection analysis showed lower reflection losses of the sinusoidal texture compared to conventional pyramids for wavelengths longer than 700nm in a silicon-air setup. It has also been demonstrated that the low cost spin coating process could be applied to the deposition of perovskite layers on the sinusoidal texture in silicon due to its relatively shallow structure size. The analysis of the electronic material properties of the sinusoidal texture in silicon shows that promising material qualities are possible.
The authors would like to thank K. Jacob, C. Klimm, I. Rudolph, and M. Wittig for their assistance with sample preparation and characterization. K. Jäger is acknowledged for fruitful discussions.