Luminescent materials that emit light in the visible range or the near infrared range
Luminescent materials and the use of such materials in anti-counterfeiting, inventory, photovoltaic, and other applications are described herein. In one embodiment, a luminescent material has the formula: [A a B b X x X′ x′ X″ x″ ][dopants], wherein A is selected from at least one of elements of Group IA; B is selected from at least one of elements of Group VA, elements of Group IB, elements of Group IIB, elements of Group IIIB, elements of Group IVB, and elements of Group VB; X, X′, and X″ are independently selected from at least one of elements of Group VIIB; the dopants include electron acceptors and electron donors; a is in the range of 1 to 9; b is in the range of 1 to 5; and x, x′, and x″ have a sum in the range of 1 to 9. The luminescent material exhibits photoluminescence having: (a) a quantum efficiency of at least 20 percent; (b) a spectral width no greater than 100 nm at Full Width at Half Maximum; and (c) a peak emission wavelength in the near infrared range.
1. A luminescent material having the formula:
[A a B b X x X′ x′ X″ x″ ][dopants],
wherein
A is cesium;
B is tin;
X, X′, and X″ are independently selected from at least one of iodine and bromine;
the dopants are present in amounts less than 5 percent in terms of elemental composition and include electron acceptors and electron donors;
a is 1;
b is in the range of 1to 3; and
x,x′, and x″ have a sum that is 1+2b;
and wherein the luminescent material exhibits photoluminescence having: (a) a quantum efficiency of at least 20 percent; (b) a spectral width no greater than 100 nm at Full Width at Half Maximum; and (c) a peak emission wavelength in the near infrared range.
2. The luminescent material of claim 1 , wherein the electron acceptors include cations corresponding to tin.
3. The luminescent material of claim 1 , wherein the electron donors include anions corresponding to Y, and Y is selected from at least one of elements of Group VIB, elements of Group VIIB, nitrate, thiocyanate, hypochiorite, sulfate, orthophosphate, metaphosphate, oxalate, methanesulfonate, trifluoromethanesulfonate, and pyrophosphate.
4. The luminescent material of claim 1 , wherein the quantum efficiency is at least 30 percent.
5. The luminescent material of claim 1 , wherein the spectral width is no greater than 80 nm at Full Width at Half Maximum.
6. The luminescent material of claim 1 , wherein the peak emission wavelength is in the range of 700 nm to 800 nm.
7. The luminescent material of claim 1 , wherein the peak emission wavelength is in the range of 900 nm to 1 μm.
8. The luminescent material of claim 1 , wherein the luminescent material has a perovskite-based microstructure, and the dopants are dispersed within the perovskite-based microstructure.
9. A luminescent material having the formula:
[A a B b X x X′ x′ X″ x″ ][dopants],
wherein
A is selected from at least one of sodium, potassium, rubidium, and cesium;
B is tin;
X, X″, and X″ are independently selected from at least one of chlorine, bromine, and iodine;
the dopants are present in amounts less than 5 percent in terms of elemental composition and include electron acceptors and electron donors;
a is in the range of 1 to 9;
b is in the range of 1 to 5; and
x, x′, and x″ have a sum in the range of 1 to 9,
wherein a is 1, and the sum of x, x′, and x″ is 1+2b.
10. The luminescent material of claim 9 , wherein A is selected from at least one of rubidium and cesium, and X, X′, and X′ are independently selected from at least one of bromine and iodine.