Luminescent materials that emit light in the visible range or the near infrared range

A method of forming a luminescent material, comprising:

• providing a first compound having the formula:
• AX, wherein A is cesium, and X is iodine;
• providing a second compound of B and Y, wherein B is tin, and Y is selected from at least one of oxygen, fluorine, chlorine, bromine, nitrate, thiocyanate, hypochlorite, sulfate, orthophosphate, metaphosphate, oxalate, methanesulfonate, trifluoromethanesulfonate, and pyrophosphate;
• depositing the first compound and the second compound on a substrate to form at least one film on the substrate;
• and
• heating the at least one film to a temperature sufficient to react the first compound and the second compound to form a luminescent material,
• wherein the luminescent material has the formula:
• [AaBbXx][dopants], wherein a is 1, b is in the range of 1 to 3, x is in the range of 3 to 7, and the dopants are derived from Y and are included in a non-zero amount less than 5 percent in terms of elemental composition.