Spectral luminescence parameters of CsPbCl₃nanocrystals dispersed in perovskite-like matrix

Abstract

Luminescence spectral and kinetic characteristics of CsPbCl3 nanocrystals, dispersed in perovskite-like CsSrCl3 matrix, have been studied under excitation by synchrotron radiation in the UV–visible spectral region (4 to 20 eV). Various time components in the decay kinetics of CsPbCl3 nanocrystals appear due to direct excitation of nanocrystals or reabsorption of the luminescence of other emitting centres. Shortening of the luminescence decay time of the CsPbCl3 nanocrystals with respect to that observed for a CsPbCl3 single crystal has been explained as evidence of quantum-size effect.

Extremely photo-luminescent microcrystalline CsPbX3 (X=Cl, Br) films obtained by amorphous-to-crystalline transformation

“…Such a direct comparison has not been made for any of heat-treated CsX:Pb [1][2][3][4][5][6][7][8][9][10][11][12][13], CsSrX 3 :Pb [14] and PbX 2 :Cs [12,15,16] (X ¼ Cl, Br) crystals studied so far, probably because of difficulties in the sample preparation technique--indeed, there occurs aggregation and/or dissociation of Pb 2þ ions during the heat treatment, as reported, for example, in [13]. The present films, prepared by crystallization from the amorphous phase, clearly show that the microcrystalline state exhibits much stronger exciton luminescence than the polycrystalline state.…”

“…In the last several years many interesting studies have been carried out on a new type of microcrystals, i.e., CsPbX 3 (X ¼ Cl, Br) microcrystals dispersed in crystal matrices, with the expectation of their possible application in fast scintillators and opto-electronic devices taking advantage of a very fast and strong free-exciton luminescence of the source compounds. The studies are based on the measurements of photoluminescence of the microcrystals thermally grown in Pb 2þ -doped CsX [1][2][3][4][5][6][7][8][9][10][11][12][13] or CsSrX 3 [14] crystals and Cs þ -doped PbX 2 [12,15,16] crystals, and deal with quantum size effects on excitons, such as confinement-induced blue shifts of exciton energy and confinement-induced changes in the decay kinetics of excitons, or aim at elucidation of growth kinetics of the microcrystals. The decay-kinetics studies reveal that the radiative decay time of the free excitons in the microcrystals is further shortened by the effect of confinement on the excitons, suggesting that the inherently strong free-exciton luminescence for CsPbX 3 can be further enhanced in intensity by the confinement effect.…”

“…Therefore, free-exciton spectroscopy is frequently conveniently used for characterizing microcrystals or quantum dots [21]. In fact, in all the existing works which deal with the CsPbX 3 (X ¼ Cl, Br) microcrystals dispersed in crystals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] or constituting films [17,18], the authors are successful in assessing the microcrystals solely by means of free-exciton spectroscopy. For example, the blue shift of free-exciton energy can be used to estimate the mean size of the microcrystals.…”

“…For example, the blue shift of free-exciton energy can be used to estimate the mean size of the microcrystals. Concerning the mean size of the microcrystals determined by free-exciton spectroscopy on a nm-scale, there has been no independent evidence from structural studies, such as by X-ray diffraction spectroscopy or by electron microscopy, both for the microcrystals dispersed in crystals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and for the microcrystals constituting films [17,18].…”

Luminescent Kinetic Characteristics of Cspbcl_3 Aggregates Dispersed in Rb_{1-X}cs_{x}cl (X=0.05-0.2) Matrices

“…The formation of nanocrystals has been confirmed by manifestation of the quantum size effect in their spectral luminescent characteristics [1][2][3][4]. High efficiency of the luminescent method of identifying the crystal type and nanocrystal sizes in the dielectric matrix has been analyzed in [5].…”