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Ultrafast Charge Delocalization Dynamics of Ambient Stable CsPbBr 3 Nanocrystals Encapsulated in Polystyrene Fiber
Author(s) -
Babu K. Justice,
Kaur Gurpreet,
Biswal Liza,
De Goutam,
Ghosh Hirendra N.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202003254
Subject(s) - materials science , delocalized electron , polystyrene , x ray photoelectron spectroscopy , nanofiber , perovskite (structure) , nanotechnology , chemical engineering , chemistry , composite material , crystallography , polymer , organic chemistry , engineering
CsPbBr 3 nanocrystals (NCs) encapsulated in a transparent polystyrene (PS) fiber matrix (CsPbBr 3 @PS) have been synthesized to protect the NCs. The ultrafast charge delocalization dynamics of the embedded NCs have been demonstrated, and the results are compared with the pristine CsPbBr 3 in toluene. The electrospinning method was employed for the preparation of CsPbBr 3 @PS fibers by using a polystyrene solution doped with pre‐synthesized CsPbBr 3 and characterized by XRD, HRTEM, and X‐ray photoelectron spectroscopy (XPS). Energy level diagrams of CsPbBr 3 and PS suggest that CsPbBr 3 @PS fibers make a type I core–shell structure. The carrier cooling for CsPbBr 3 @PS fibers is found to be much slower than pure CsPbBr 3 NCs. This observation suggests that photoexcited electrons from CsPbBr 3 NCs get delocalized from the conduction band of the perovskite to lowest unoccupied molecular orbital (LUMO) of the PS fiber matrix. The CsPbBr 3 @PS fibers possess remarkable stability under ambient conditions as well as in water over months. The clear understanding of charge carrier relaxation dynamics of CsPbBr 3 confined in PS fibers could help to design robust optoelectronic devices.