Quantum-splitting oxide-based phosphors, method of producing, and rules for designing the same

A method of making a quantum-splitting phosphor, said method comprising the steps of:

• (1) selecting a desired final composition of said phosphor such that said phosphor is activated by at least praseodymium and manganese ions;
• (2) mixing together oxygen-containing compounds of praseodymium and manganese and materials selected from the group consisting of oxygen-containing compounds of strontium, calcium, aluminum, boron, gadolinium, lanthanum, and magnesium in quantities so as to achieve said desired final composition of said phosphor;
• (3) forming a substantially homogeneous mixture of said oxygen-containing compounds;
• and (4) firing said substantially homogeneous mixture in a non-oxidizing atmosphere at a temperature and for a time sufficient to result in said desired final composition and to maintain substantially all of said praseodymium ions in a 3+ valence state and said manganese ions in a 2+ valence state.

A method for designing quantum-splitting phosphors in which a host lattice is activated by at least Pr3+ and Mn2+ ions, said method comprising:

• ensuring that Pr3+ is incorporated in said host such that a 4f5d band of said Pr3+ is located above a 1S0 state of said Pr3+;
• ensuring that said 4f5d band and said 1S0 state are positioned below a conduction band of said host where said Pr3+ is incorporated in a lattice having a band gap greater than about 5 eV;
• ensuring that a site symmetry of said host lattice for said Pr3+ has been chosen having an effective crystal field strength and an effective Pr3+-to-host lattice bond distance;
• and
• selecting a sufficient amount of Mn2+ to incorporate in said host lattice to convert a part of radiation emitted by Pr3+ in a UV range to visible light.

A light source comprising an evacuated housing;

• a VUV radiation source located within said housing;
• and a phosphor located within said housing and adapted to be excited by said VUV radiation source;
• said phosphor comprising an oxide-based quantum-splitting phosphor which comprises an oxide of an element selected from the group consisting of aluminum and boron, at least one positive counterion selected from the group consisting of strontium, calcium, lanthanum, and magnesium;
• said oxide being doped with Pr3+ and Mn2+ ions;
• said phosphor exhibiting a quantum-splitting behavior when irradiated by said VUV radiation.