The present invention firstly relates to a security feature for a security or value document. The security feature comprises a zinc sulfide lurninophore in the form of particles. The zinc sulfide lurninophore has the general chemical formula ZnS: Cu.sub.x, M.sub.y, X.sub.z; here, M represents one or more elements from a group comprising the chemical elements Co, In and Ni; X represents one or more elements from a group comprising the halides F, Cl, Br and I; and the following applies: 0 < x < 0.002 and 0 ≤ y < 0.00015 and 0 ≤ z < 0.00050. The particles each have cubic phase portions and hexagonal phase portions. When excited by an electrical field, the zinc sulfide luminophore emits a first radiation in the range of the light spectrum between 580 nm and 780 nm. When excited by heating the luminophore to a temperature between 100° C. and 150° C., the zinc sulfide luminophore emits a second radiation in the light spectrum. Furthermore, the invention relates to a security and value document, which may for example be a bank note or a passport, an identity card, a driving license or a postage stamp. The invention also relates to a method for detecting and/or verifying the security feature according to the invention.

An electronic device including first to third light emitting regions and a dummy region is provided. The electronic device includes a base layer, and a display element layer including a pixel defining film on the base layer, light emitting elements divided by the pixel defining film, and a reduction preventing layer containing a reduction preventing agent, and the light emitting elements each include an electron transport region containing a metal oxide. The electronic device may have improved electron transport function of the electron transport region by the reduction preventing agent contained in the reduction preventing layer, thereby improving the luminous efficiency.

A composition can include a copper containing nanocrystal.

A quantum dot according to the present application includes a surface including polar planes accounting for an area percentage of 70% or more, or a surface including non-polar planes accounting for an area percentage of 70% or more.

A composition can include a copper containing nanocrystal.

A security feature is presented for a security or value document. The security feature comprises a zinc sulfide luminophore in the form of particles. The zinc sulfide luminophore has the general chemical formula ZnS:Cu.sub.x, M.sub.y, X.sub.z; here, M represents one or more elements from a group comprising the chemical elements Co, In and Ni; X represents one or more elements from a group comprising the halides F, Cl, Br and I; and the following applies: 0<x<0.002 and 0::; y<0.00015 and 0::; z<0.00050. The particles each have cubic phase portions and hexagonal phase portions. When excited by an electrical field, the zinc sulfide luminophore emits a first radiation in the range of the light spectrum between 580 nm and 780 nm. When excited by heating the luminophore to a temperature between 100 C. and 150 C., the zinc sulfide luminophore emits a second radiation in the light spectrum.

A composition can include a copper containing nanocrystal.