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B‐Site Co‐Alloying with Germanium Improves the Efficiency and Stability of All‐Inorganic Tin‐Based Perovskite Nanocrystal Solar Cells
Author(s) -
Liu Maning,
Pasanen Hannu,
AliLöytty Harri,
Hiltunen Arto,
Lahtonen Kimmo,
Qudsia Syeda,
Smått JanHenrik,
Valden Mika,
Tkachenko Nikolai V.,
Vivo Paola
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202008724
Subject(s) - nanocrystal , tin , materials science , germanium , perovskite (structure) , photoluminescence , nanotechnology , quantum yield , quantum dot , nanostructure , chemical engineering , optoelectronics , silicon , metallurgy , optics , physics , engineering , fluorescence
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.