B-Site Co-Alloying with Germanium Improves the Efficiency and Stability of All-Inorganic Tin-Based Perovskite Nanocrystal Solar Cells

Maning Liu, Hannu Pasanen, Harri Ali-Löyttö, Arto Hiltunen, Kimmo Lahtonen, Syeda Qudsia, Jan-Henrik Smått, Mika Valden, Nikolai Tkachenko, Paola Vivo*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)
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Abstract

Colloidal lead-free perovskite nanocrystals have recently received extensive attention because of their facile synthesis, the outstanding size-tunable optoelectronic properties, and less or no toxicity in their commercial applications. Tin (Sn) has so far led to the most efficient lead-free solar cells, yet showing highly unstable characteristics in ambient conditions. Here, we propose the synthesis of all-inorganic mixture Sn-Ge perovskite nanocrystals, demonstrating the role of Ge 2+ in stabilizing Sn 2+ cation while enhancing the optical and photophysical properties. The partial replacement of Sn atoms by Ge atoms in the nanostructures effectively fills the high density of Sn vacancies, reducing the surface traps and leading to a longer excitonic lifetime and increased photoluminescence quantum yield. The resultant Sn-Ge nanocrystals-based devices show the highest efficiency of 4.9 %, enhanced by nearly 60 % compared to that of pure Sn nanocrystals-based devices.

Original languageEnglish
Pages (from-to)22117-22125
JournalAngewandte Chemie International Edition
Volume59
Issue number49
DOIs
Publication statusPublished - 2020
MoE publication typeA1 Journal article-refereed

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