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High Stability and Temperature‐Dependent Photoluminescence of Orthorhombic CsPbI 3 Perovskite Nanoparticles
Author(s) -
Tang Bing,
Ruan Lin Ji,
Qin Changyun,
Shu Ang,
He Huimei,
Ma Ying
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202000498
Subject(s) - materials science , photoluminescence , orthorhombic crystal system , perovskite (structure) , thermal stability , nanocrystal , exciton , band gap , nanoparticle , optoelectronics , chemical physics , nanotechnology , chemical engineering , crystal structure , crystallography , condensed matter physics , chemistry , physics , engineering
High thermal stability of all‐inorganic perovskite nanocrystals (NCs) offers their potential application in various fields such as solar cells and light‐emitting diodes. However, the cubic cesium lead iodide (α‐CsPbI 3 ) with the most appropriate bandgap for light harvesting is thermodynamically unstable at room temperature and spontaneously transforms into the undesired orthorhombic δ‐CsPbI 3 . Here, a simple method is demonstrated to synthesize orthorhombic γ‐CsPbI 3 NCs using 3‐aminopropyl triethoxysilane molecules as capping ligands. The crystalline structure and morphology of these γ‐CsPbI 3 NCs hardly change after exposure to ethanol even though they are capped with fewer ligands. Their high stability is also demonstrated by retaining their photoluminescence (PL) intensity after heating/cooling cycles in the range of 295–375 K, in contrast to a quick destruction of α‐CsPbI 3 NCs under the same condition. More importantly, temperature‐dependent PL spectra reveal that the exciton/electron–phonon coupling and exciton recombination process of these γ‐CsPbI 3 NCs strongly depend on their particle sizes. This finding may enable versatile design of stable γ‐CsPbI 3 NCs with different sizes meeting diverse demands for various applications.