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Facile Synthesis of Colloidal Lead Halide Perovskite Nanoplatelets via Ligand-Assisted Reprecipitation
Published on: October 1, 2019
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Understanding the Surface Properties of Halide Exchanged Cesium Lead Halide Nanoparticles
Emily Grace Ripka1, Christina R Deschene1, John M Franck1
1Department of Chemistry , Syracuse University , Syracuse , New York 13244 , United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 23, 2018
Summary
Ligand additions during perovskite nanoparticle processing are crucial for maintaining surface passivation and photoluminescence quantum yield (QY). Careful control of ligands during purification and halide exchange is essential for stable, high-QY CsPbBr3 and mixed-halide nanoparticles.
Area of Science:
- Materials Science
- Nanotechnology
- Photophysics
Background:
- Cesium lead halide perovskite nanoparticles (NPs) are promising for optoelectronic applications due to their tunable properties.
- Surface passivation is critical for maintaining the photoluminescence quantum yield (QY) of perovskite NPs.
- Postsynthetic processing, including purification and halide exchange, can significantly alter NP surface properties.
Purpose of the Study:
- To characterize the surface properties of CsPbBr3 and CsPbBr3-xI_x perovskite NPs after postsynthetic processing.
- To investigate the relationship between NP composition, ligand binding, and photoluminescence quantum yield (QY).
- To understand the role of ligand additions during purification and halide exchange.
Main Methods:
- Diffusion Ordered Nuclear Magnetic Resonance (DOSY) spectroscopy to study NP-ligand interactions.
- Quantification of photoluminescence quantum yield (QY) as a function of halide and ligand exchange.
- Characterization of ligand density on NP surfaces with varying halide composition.
Main Results:
- Ligand binding strength and QY decrease with successive purification/exchange steps without proper acid-base ligand addition.
- Ligands are localized at the NP surface, passivating surface sites.
- Ligand density decreases with increasing CsPbI3 content in CsPbBr3-xI_x NPs, impacting QY.
Conclusions:
- Postsynthetic processing requires careful addition of ion-ligand moieties to maintain the properties of CsPbBr3 NPs.
- Surface ligand binding and photostability differ intrinsically between CsPbBr3 and mixed-halide CsPbBr3-xI_x NPs.
- Understanding these surface interactions is key to optimizing perovskite NP performance.
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