High Quantum Yield Blue Emission from Lead-Free Inorganic Antimony Halide Perovskite Colloidal Quantum Dots

Abstract

Colloidal quantum dots (QDs) of lead halide perovskite have recently received great attention owing to their remarkable performances in optoelectronic applications. However, their wide applications are hindered from toxic lead element, which is not environment- and consumer-friendly. Herein, we utilized heterovalent substitution of divalent lead (Pb) with trivalent antimony (Sb) to synthesize stable and brightly luminescent CsSbBr QDs. The lead-free, full-inorganic QDs were fabricated by a modified ligand-assisted reprecipitation strategy. A photoluminescence quantum yield (PLQY) was determined to be 46% at 410 nm, which was superior to that of other reported halide perovskite QDs. The PL enhancement mechanism was unraveled by surface composition derived quantum-well band structure and their large exciton binding energy. The Br-rich surface and the observed 530 meV exciton binding energy were proposed to guarantee the efficient radiative recombination. In addition, we can also tune the inorganic perovskite QD (CsSbX) emission wavelength from 370 to 560 nm via anion exchange reactions. The developed full-inorganic lead-free Sb-perovskite QDs with high PLQY and stable emission promise great potential for efficient emission candidates.

Halide Perovskite Nanocrystals for Next‐Generation Optoelectronics

“…e) Tunable PL spectra for Cs 3 Sb 2 X 9 (X = Cl x Br y I 1− x − y ,0 ≤ x , y ≤ 1) nanocrystals prepared by the anion exchange from Cs 3 Sb 2 Br 9 nanocrystals. Reproduced with permission . Copyright 2017, American Chemical Society.…”

Light Generation in Lead Halide Perovskite Nanocrystals: LEDs, Color Converters, Lasers, and Other Applications

“…The significant progress that has been made for LHP‐NC‐based LEDs in terms of luminous efficiency has been offset by their unsatisfactory operational stability, leaving the potential of this cutting‐edge display technology uncertain. In principle, without directional ion migration driven by an applied electric field, LHP‐NCs that work as color converter under only optical excitation are significantly more stable, and all of the considerations concerning electrical features, e.g., charge carrier transport and injection, and related technical questions, e.g., film morphology and compatibility, can be neglected ( Table 2 ). Moreover, quasi‐2D LHP NCs, and especially the lead‐free halide double perovskite NCs that are difficult to use in LEDs, can be used appropriately in various applications under optical excitation.…”

“…In comparison to the role of emitters in LEDs, lead‐free double perovskite NCs, e.g., Cs 2 AgInCl 6 , exhibit superior performance as phosphor in white LED because of their broad band emission . With a high PLQY of 86% and a superior operation lifetime of over 10 000 h with continuous illumination by ultraviolet light in the ambient environment, such lead‐free double perovskite NCs could be used in general lighting.…”

Bleifreie Halogenid‐Perowskit‐Nanokristalle: Kristallstrukturen, Synthese, Stabilitäten und optische Eigenschaften

“…Im Gegensatz dazu wird MA 3 Bi 2 Cl 9 gebildet, indem jede dritte Bi‐Schicht entlang der (110)‐Richtung der ursprünglichen 3D‐Struktur entfernt wird; um den Ladungsausgleich aufrechtzuerhalten, müssen auch die (001)‐Ebenen geschnitten werden, wobei 2/3 der Bi‐Atome übrig bleiben, was zur endgültigen 1D‐Struktur führt. Ebenso weist die Kristallstruktur der Cs 3 Sb 2 Br 9 ‐NCs eine 2D‐Schichtstruktur auf, die mit ihrem Bulk‐Material konsistent ist, wie in Abbildung a dargestellt wird . A 3 Sb 2 I 9 (A=MA oder Cs) kristallisiert in der 0D‐Dimerphase, wobei allerdings die Einführung von Cl eine Phasenumwandlung von der 0D‐Dimerphase zur 2D‐Schichtphase induzieren kann (Abbildung b).…”