Electronic energy levels of RbCdBr₃ crystal

Abstract

The RbCdBr 3 crystal that consists of edge shared [CdBr 6 ] 4À octahedrons was grown by using the Bridgman growth technique and its electronic energy levels are investigated by measuring the excitation and the emission spectra. An energy level diagram for electronic energy levels of RbCdBr 3 -crystal is constructed by using the observed excitation spectra and symmetry considerations.

Highly Efficient and Ultralong Afterglow Emission with Anti‐Thermal Quenching from CsCdCl3 : Mn Perovskite Single Crystals

“…For D 3d symmetry, the possible absorption transition corresponds to [a 2u + e u ]!a 1g , while the PL transition is a 1g !e 1 . [25] For the observed PL, the exhibited broadband emission with large stokes shift is due to the localized charge distribution (proved by band structure calculation as discussed below) and carrier-phonon coupling, also known as STEs. The emission from C 3v or D 3d should originate from the triplet exciton, as the singlet exciton usually lies in the UV region with short PL lifetime (ns), [24,25] while the triplet exciton-based emission lies in the visible light region.…”

“…So the observed absorption should comprise of these transitions: [e+a 1 ]→a 1 and [e+a 1 ]→e, a 1 . For D 3 d symmetry, the possible absorption transition corresponds to [a 2u +e u ]→a 1g , while the PL transition is a 1g →e 1 [25] . For the observed PL, the exhibited broadband emission with large stokes shift is due to the localized charge distribution (proved by band structure calculation as discussed below) and carrier‐phonon coupling, also known as STEs.…”

“…Interestingly, we found that the CsCdCl 3 (hex) has two PL bands (band 2 and band 3) at low temperature while there is only one PL band in the cubic phase. This might be ascribed to the emission from [CdCl 6 ] 4 octahedrons with different symmetries in the two phases, as both C 3 v symmetry and D 3 d symmetry exist in CsCdCl 3 (hex), while only O h symmetry [CdCl 6 ] 4− octahedrons exist in CsCdCl 3 (cub) [24, 25] . In CsCdCl 3 (hex), for C 3 v symmetry, the transition between a 1 and e is allowed [24] .…”

“…For the observed PL, the exhibited broadband emission with large stokes shift is due to the localized charge distribution (proved by band structure calculation as discussed below) and carrier‐phonon coupling, also known as STEs. The emission from C 3 v or D 3 d should originate from the triplet exciton, as the singlet exciton usually lies in the UV region with short PL lifetime (ns), [24, 25] while the triplet exciton‐based emission lies in the visible light region. The triplet exciton‐based emission is further supported by the long PL lifetime (Figure S8).…”

Highly Efficient and Ultralong Afterglow Emission with Anti‐Thermal Quenching from CsCdCl3 : Mn Perovskite Single Crystals

“…This might be ascribed to the emission from [CdCl 6 ] 4 octahedrons with different symmetries in the two phases, as both C 3v symmetry and D 3d symmetry exist in CsCdCl 3 (hex), while only O h symmetry [CdCl 6 ] 4À octahedrons exist in CsCdCl 3 (cub). [24,25] In CsCdCl 3 (hex), for C 3v symmetry, the transition between a 1 and e is allowed. [24] So the observed absorption should comprise of these transitions: [e + a 1 ]!a 1 and [e + a 1 ]!e, a 1 .…”