Abstract: An electro-optical device includes: (1) a first electrode layer; (2) a second electrode layer; and (3) a middle layer disposed between the first electrode layer and the second electrode layer. The middle layer includes a material having the formula: [AaBbXxX?x?X?x?], where A is selected from potassium, rubidium, and cesium; B is selected from germanium, tin, and lead; X, X?, and X? are independently selected from fluorine, chlorine, bromine, and iodine; a is in the range of 1 to 9; b is in the range of 1 to 5; a sum of x, x?, and x? is in the range of 1 to 9; and the material is at least one of n-doped and p-doped.

Abstract: An electro-optical device includes: (1) a first electrode layer; (2) a second electrode layer; and (3) a middle layer disposed between the first electrode layer and the second electrode layer. The middle layer includes a material having the formula: [AaBbXxX?x?X?x?], where A is selected from potassium, rubidium, and cesium; B is selected from germanium, tin, and lead; X, X?, and X? are independently selected from fluorine, chlorine, bromine, and iodine; a is in the range of 1 to 9; b is in the range of 1 to 5; a sum of x, x?, and x? is in the range of 1 to 9; and the material is at least one of n-doped and p-doped.

Abstract: Luminescent materials and the use of such materials in anti-counterfeiting, inventory, photovoltaic, and other applications are described herein. In one embodiment, a method of forming a luminescent material includes: (1) providing a source of A and X, wherein A is selected from at least one of elements of Group 1, and X is selected from at least one of elements of Group 17; (2) providing a source of B, wherein B is selected from at least one of elements of Group 14; (3) subjecting the source of A and X and the source of B to vacuum deposition to form a set of films adjacent to a substrate; and (4) heating the set of films to a temperature in the range of 120° C. to 350° C. to form a luminescent material adjacent to the substrate, wherein the luminescent material includes A, B, and X.

Abstract: Described herein are optical devices including resonant cavity structures. In one embodiment, an optical fiber includes: (1) an elongated core including an outer surface; (2) an inner reflector disposed adjacent to the outer surface of the core and extending substantially along a length of the core; (3) an outer reflector spaced apart from the inner reflector and extending substantially along the length of the core; and (4) an emission layer disposed between the outer reflector and the inner reflector and extending substantially along the length of the core, the emission layer configured to emit radiation that is guided within the optical fiber.

Abstract: Luminescent materials and the use of such materials in anti-counterfeiting, inventory, photovoltaic, and other applications are described herein. In one embodiment, a method of forming a luminescent material includes: (1) providing a source of A and X, wherein A is selected from at least one of elements of Group IA, and X is selected from at least one of elements of Group VIIB; (2) providing a source of B, wherein B is selected from at least one of elements of Group IVB; (3) subjecting the source of A and X and the source of B to vacuum deposition to form a set of films adjacent to a substrate; and (4) heating the set of films to a temperature in the range of 120° C. to 350° C. to form a luminescent material adjacent to the substrate, wherein the luminescent material includes A, B, and X.

Abstract: 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: [AaBbXxX?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.

Abstract: Apparatus, system, and method to authenticate and identify objects using nanoparticles are described herein. In one embodiment, a computer-readable storage medium includes executable code to: (1) derive an index based on an authentication image of a marking; (2) select a reference image of the marking based on the index; (3) compare the authentication image with the reference image to determine whether the authentication image matches the reference image; and (4) produce an indication of authenticity based on whether the authentication image matches the reference image.

Abstract: Described herein are techniques for authenticating and identifying objects using markings formed with correlated random patterns. In one embodiment, an object to be authenticated includes a substrate and a marking adjacent to the substrate. The marking includes a luminescent material distributed in accordance with a correlated random pattern, and the luminescent material exhibits photoluminescence having a quantum efficiency of at least 10 percent.