NOVELTY - A nanocrystal particle comprises at least one semiconductor material and at least one halogen element, where the nanocrystal particle has a core-shell structure including a core comprising a first semiconductor nanocrystal; and a shell surrounding the core and comprising a crystalline or amorphous material, and where the halogen element is present as being doped in it or as a metal halide.    USE - The nanocrystal particle is useful in the manufacture of a device, where the device is a light emitting diode, an organic light emitting diode, a sensor, a solar cell, an imaging sensor, or a liquid crystal display (claimed).    ADVANTAGE - The nanocrystal particle has enhanced light emitting properties, such as a high quantum yield.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a process for synthesizing a nanocrystal particle, which involves: obtaining a first mixture including a first precursor, a ligand compound, and a solvent; optionally heating the first mixture; contacting a source of a halogen element, a second precursor, and optionally a first nanocrystal with the first mixture, which is optionally heated, to obtain a second mixture; and heating the second mixture to a reaction temperature to react the first precursor and the second precursor to obtain a nanocrystal particle comprising a semiconductor material and the halogen;    (2) a device which comprises the nanocrystal particle; and    (3) a nanoparticle comprising at least one semiconductor material and at least one halogen element, where the nanocrystal particle has a core-shell structure including a core comprising a first semiconductor nanocrystal, and a shell surrounding the core and comprising a crystalline or amorphous material, where the halogen element is present as being doped in it or as a metal halide, and where the first semiconductor nanocrystal comprises a metal selected from a Group II metal, a Group III metal, a Group IV metal, and a combination, and where the crystalline or amorphous material of the shell comprises a metal which is different from the metal included in the first semiconductor nanocrystal of the core and which is selected from a Group I metal, a Group II metal, a Group III metal, a Group IV metal, and a combination.