Preferred Growth Direction by PbS Nanoplatelets Preserves Perovskite Infrared Light Harvesting for Stable, Reproducible, and Efficient Solar Cells

• Published in: Advanced energy materials 2020-12, Vol.10 (46), p.n/a
• Main Authors: Sánchez‐Godoy, Humberto Emmanuel, Erazo, Eider Ansisar, Gualdrón‐Reyes, Andrés Fabián, Khan, Ali Hossain, Agouram, Said, Barea, Eva Maria, Rodriguez, Rubén Arturo, Zarazúa, Isaac, Ortiz, Pablo, Cortés, María Teresa, Muñoz‐Sanjosé, Vicente, Moreels, Iwan, Masi, Sofia, Mora‐Seró, Iván
• Format: Article
• Language: English
• Subjects: Control stability; Crystal growth; Crystal structure; Current efficiency; formamidinium; Grains; Infrared radiation; PbS nanoplatelets; perovskite stability; Perovskites; Phase stability; Photovoltaic cells; Reproducibility; Solar cells
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202002422

Formamidinium‐based perovskite solar cells (PSCs) present the maximum theoretical efficiency of the lead perovskite family. However, formamidinium perovskite exhibits significant degradation in air. The surface chemistry of PbS has been used to improve the formamidinium black phase stability. Here, the use of PbS nanoplatelets with (100) preferential crystal orientation is reported, to potentiate the repercussion on the crystal growth of perovskite grains and to improve the stability of the material and consequently of the solar cells. As a result, a vertical growth of perovskite grains, a stable current density of 23 mA cm−2, and a stable incident photon to current efficiency in the infrared region of the spectrum for 4 months is obtained, one of the best stability achievements for planar PSCs. Moreover, a better reproducibility than the control device, by optimizing the PbS concentration in the perovskite matrix, is achieved. These outcomes validate the synergistic use of PbS nanoplatelets to improve formamidinium long‐term stability and performance reproducibility, and pave the way for using metastable perovskite active phases preserving their light harvesting capability. PbS nanoplatelets (NPLs) used as an external additive with (100) preferential crystal orientation improve a formamidinium‐based perovskite material and solar cell stability. A stable current density of 23 mA cm−2 for 4 months is recorded along with an improved reproducibility, demonstrating the potential of the interaction between the (100) facets of the NPLs and the perovskite α‐phase.