A core-shell quantum dot comprising zinc, a core comprising a first semiconductor nanocrystal material; and a semiconductor nanocrystal shell disposed on the core, wherein the core-shell quantum dot does not comprise cadmium, and does comprise zinc, tellurium, selenium, and aluminum.

A core-shell quantum dot comprising zinc, a core comprising a first semiconductor nanocrystal material; and a semiconductor nanocrystal shell disposed on the core, wherein the core-shell quantum dot does not comprise cadmium, and does comprise zinc, tellurium, selenium, and aluminum.

A composition may include an aqueous base and at least one identifying additive. The at least one identifying additive may include an alkaline earth metal compound and a fluorescence activator. The at least one identifying additive may be configured such that the composition emits fluorescent light having an identifying characteristic different from a characteristic of a surface against which the identifying characteristic is viewed. A composition may include an aqueous base and at least one identifying additive including an alkaline earth metal compound and a fluorescence activator including at least one other inorganic element. The at least one identifying additive may be configured such that the composition emits fluorescent light having an identifying characteristic. A label or packaging for identifying at least one of an object and a source of the object may include a composition including at least one identifying additive associated with a surface associated with the label or packaging.

A composition may include an aqueous base and at least one identifying additive. The at least one identifying additive may include an alkaline earth metal compound and a fluorescence activator. The at least one identifying additive may be configured such that the composition emits fluorescent light having an identifying characteristic different from a characteristic of a surface against which the identifying characteristic is viewed. A composition may include an aqueous base and at least one identifying additive including an alkaline earth metal compound and a fluorescence activator including at least one other inorganic element. The at least one identifying additive may be configured such that the composition emits fluorescent light having an identifying characteristic. A label or packaging for identifying at least one of an object and a source of the object may include a composition including at least one identifying additive associated with a surface associated with the label or packaging.

A potassium hexafluoromanganate is represented by General Formula: K.sub.2MnF.sub.6, and a diffuse reflectance with respect to light having a wavelength of 310 nm is 20% or more.

A potassium hexafluoromanganate is represented by General Formula: K.sub.2MnF.sub.6, and a diffuse reflectance with respect to light having a wavelength of 310 nm is 20% or more.

A europium-doped β-sialon phosphor particle. When the element concentration of a Si atom on the surface portion of the particle that is obtained by analyzing a cross section of the phosphor particle by the energy dispersive X-ray analysis method is indicated by Ps [at %], and the element concentration of a Si atom near the center of the particle that is obtained by an analysis by the same method is indicated by Pc [at %], the Pc-Ps value is 3 at % or more.

A europium-doped β-sialon phosphor particle. When the element concentration of a Si atom on the surface portion of the particle that is obtained by analyzing a cross section of the phosphor particle by the energy dispersive X-ray analysis method is indicated by Ps [at %], and the element concentration of a Si atom near the center of the particle that is obtained by an analysis by the same method is indicated by Pc [at %], the Pc-Ps value is 3 at % or more.

Mechanoluminescent devices and articles, such as wearable articles, that include mechanoluminescent devices. The mechanoluminescent devices may have a lateral type architecture or a vertical type architecture. The mechanoluminescent devices may be sensors, including pressure sensors.

Mechanoluminescent devices and articles, such as wearable articles, that include mechanoluminescent devices. The mechanoluminescent devices may have a lateral type architecture or a vertical type architecture. The mechanoluminescent devices may be sensors, including pressure sensors.