A study of the effects of a thermally evaporated nanoscale CsBr layer on the optoelectronic properties and stability of formamidinium-rich perovskite solar cells
Richard K. Koech,
Reisya Ichwani,
Julia L. Martin,
Deborah O. Oyewole,
Omolara V. Oyelade,
Yusuf A. Olanrewaju,
Dahiru M. Sanni,
Sharafadeen A. Adeniji,
Ronald L. Grimm,
Abdulhakeem Bello,
Oluwaseun K. Oyewole,
Esidor Ntsoenzok,
Winston O. Soboyejo
Affiliations
Richard K. Koech
Department of Materials Science and Engineering, African University of Science and Technology, P.M.B. 681, Garki-Abuja, Federal Capital Territory, Nigeria
Reisya Ichwani
Department of Mechanical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA
Julia L. Martin
Department of Chemistry and Biochemistry, Life Science and Engineering Center, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA
Deborah O. Oyewole
Department of Mechanical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA
Omolara V. Oyelade
Department of Theoretical and Applied Physics, African University of Science and Technology, P.M.B. 681, Garki-Abuja, Federal Capital Territory, Nigeria
Yusuf A. Olanrewaju
Department of Materials Science and Engineering, African University of Science and Technology, P.M.B. 681, Garki-Abuja, Federal Capital Territory, Nigeria
Dahiru M. Sanni
Department of Theoretical and Applied Physics, African University of Science and Technology, P.M.B. 681, Garki-Abuja, Federal Capital Territory, Nigeria
Sharafadeen A. Adeniji
Department of Theoretical and Applied Physics, African University of Science and Technology, P.M.B. 681, Garki-Abuja, Federal Capital Territory, Nigeria
Ronald L. Grimm
Department of Chemistry and Biochemistry, Life Science and Engineering Center, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA
Abdulhakeem Bello
Department of Materials Science and Engineering, African University of Science and Technology, P.M.B. 681, Garki-Abuja, Federal Capital Territory, Nigeria
Oluwaseun K. Oyewole
Department of Mechanical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA
Esidor Ntsoenzok
CEMHTI-CNRS Site Cyclotron, 3A rue de la férollerie, 45071 Orléans, France
Winston O. Soboyejo
Department of Mechanical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA
Incorporation of cesium (Cs) into the perovskite layer has become a good strategy to boost the stability and power conversion efficiency (PCE) of perovskite solar cells (PSCs). However, a suitable and scalable method of Cs incorporation in a perovskite film that does not cause a significant increase in the optical bandgap is needed. In this paper, we introduce a thin layer of CsBr into a formamidinium (FA)-rich mixed halide perovskite film using the thermal evaporation technique. The effects of the thickness of the CsBr layer on the microstructural, structural, and optoelectronic properties and surface chemical states of the perovskite film are then studied. The results indicate that the CsBr layer thickness is able to tune the microstructural and optoelectronic properties of the perovskite film. Planar PSCs fabricated with different thicknesses of CsBr layers in the perovskite absorber exhibited different photovoltaic performance characteristics. The CsBr-modified PSC device with a 50 nm layer of CsBr in the perovskite layer showed a better PCE of 16.19% ± 0.17%, which was about 15% higher than that of the control device, and was able to retain nearly 70% of its initial PCE value after 120 days of storage in an unencapsulated state.
