As an effective method to improve
the optical properties and stability
of perovskite matrix, doped halide perovskites have attracted extensive
attention in the field of optoelectronic applications. Herein, a series
of all inorganic lead-free Te4+-doped Cs2ZrCl6 vacancy-ordered perovskites were successfully synthesized
with different Te-doping concentrations by a solvothermal method,
and deliberate Te4+-doping results in green-yellow triplet
self-trapped exciton (STE) emission with a high photoluminescence
quantum yield (PLQY) of 49.0%. The efficient energy transfer was observed
from singlet to triplet emission. Further, the effects of A-site Rb
alloying on the optical properties and stability were investigated.
We found that A-site Rb alloying and C-site cohalogenation did not
change the luminescence properties of Te4+, but the addition
of a small amount of Rb+ can improve the PL intensity and
moisture stability. Our results provide physical insights into the nS2 Te4+-ion-doping-induced emissive
mechanism and shed light on improving the environmental stability
for further applications.
Lead-free lower-dimensional organic−inorganic metal halide materials have recently triggered intense research because of their excellent photophysical properties and chemical stability. Herein, we report a novel zero-dimensional (0D) organic−inorganic hybrid single crystal (TMA) 2 SbCl 5 •DMF (TMA = N(CH 3 ) 3 , DMF= HCON(CH 3 ) 2 ), which exhibits typical selftrapped exciton (STE) emission with an efficient yellow emission at 630 nm and high photoluminescence quantum yield (PLQY) of 67.2%. The dual STE emission is attributed to the singlet and triplet STEs in inorganic [SbCl 5 ] 2− , respectively. Further, an ab initio molecular dynamics simulation was performed to estimate the stability of crystal structure at room temperature. The calculated excited-state structure indicates that the deformation parameter (Δd) of the excited-state structure is larger than that of the ground state, illustrating the origin of a large Stokes shift. These results indicate that these new 0D lead-free organic−inorganic hybrid metal halides are promising luminescent materials for optoelectronic applications.
Environmental friendly metal hybrid halides show great promise for white light emitting diode (WLED) applications due to their unique optical properties. Herein, a lead-free blue-light excited red-emitting Mn2+-based hybrid halide...
Controlling the structure of halide perovskites through component engineering, and thus revealing the changes in luminescence properties caused by the conversion of crystal structure, is of great significance. Herein, we report a controllable synthetic strategy of threedimensional (3D) Cs 2 KInCl 6 and zero-dimensional (0D) (Cs/ K) 2 InCl 5 (H 2 O) halide perovskites by changing the Cs/K feed ratio. 3D Cs 2 KInCl 6 double perovskites are obtained at the Cs/K feed ratio of 1:1, while 0D (Cs/K) 2 InCl 5 (H 2 O) perovskites are formed at the Cs/K feed ratio of 2:1. Further, a reversible crystal structure transformation between 3D Cs 2 KInCl 6 double perovskites and 0D (Cs/K) 2 InCl 5 (H 2 O) perovskites can be achieved by subsequent addition of metal-salt precursors. In addition, the emission efficiency of two perovskite structures can be greatly boosted by breaking the forbidden transition through Sb doping, and as a result, a novel green/yellow reversible emission switch is generated. Meanwhile, the relationship between perovskite structure and luminescence mechanism has been systematically revealed. These environmentally stable halide perovskites have great potential to be applied in optoelectronic devices.
All-inorganic metal halide materials are eye-catching because of their interesting and excellent optoelectronic properties. In this report, a series of Mn 2+ -doped CscdBr 3 perovskite materials were synthesized by grinding in a mortar. The strong photoluminescence (PL) emission band at 650 nm and its PLQY reaches 54.42% after doping with modest Mn 2+ . The enhanced PL emission is the result of a weak ferromagnetic coupling of Mn−Mn pair to form a magnetic polaron and self-trapped exciton (STE), and the energy transfer from the d−d transition of a single Mn to STE and Mn−Mn pair level is very effective. The doping also enhances the nonlinear optical response of the material by their laser excitations. The photophysical mechanism of Mn-doped CsCdBr 3 has been discussed, and the specific conversion process from the bandedge to each charge state has been analyzed in detail. This kind of material may have significant applications in spintronic or optoelectronic devices.
The rich phase structures of perovskite derivatives have attracted extensive attention and can be applied in the fields of optoelectronics due to their high emission efficiency and tunable emission. Herein, we explored a phase-selective solution synthetic route to obtain different Cd-based perovskite derivatives. First, the pristine tetragonal Cs 7 Cd 3 Br 13 was obtained by a solvothermal method, and its photoluminescence quantum yield (PLQY) was boosted from 8.28% to 57.62% after appropriate Sb 3+ doping. Furthermore, halogen substitution was adopted to modify Sb:Cs 7 Cd 3 Br 13 and produced a series of Cd-based perovskite derivatives with different crystal structures and tunable emission from cyan to orange (517−625 nm). The mechanisms behind such experimental phenomena were further investigated and discussed on the basis of material characterization and theoretical computation. This study presented an effective strategy to synthesize bright Cd-based perovskite derivatives with different structures and modulated emission, and it also provided insights to understand the structure/emission modulation via halogen substitution.
Metal halide perovskites (MHPs) have attracted extensive attention due to their excellent optoelectronic properties. Among them, layered two-dimensional (2D) metal halide materials with special structures have attracted extensive attention due to their superior stability and optoelectronic properties. Here, we report the 2D Ruddlesden−Popper (RP) phase Cs 3 Cd 2 Cl 7 synthesized by a solvothermal method, and the photoluminescence quantum yields (PLQYs) of the pristine Cs 3 Cd 2 Cl 7 sample (PLQY ∼ 10%) can be increased to 68 ± 5% through appropriate Sb 3+ doping. This should be the highest PLQY of all reported allinorganic RP-phase Cd-based perovskites so far. Our results indicate that the highly efficient cyan emission can be attributed to the common self-trapped exciton (STE) emission of the triplet states of Cd 2+ and Sb 3+ induced by strong electron−phonon coupling, and Sb 3+ :Cs 3 Cd 2 Cl 7 has excellent structural and spectral stability. This new material should be a promising candidate for optoelectronic applications in the future.
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