A doped-type metal sulfide phosphor nanoparticle dispersion, comprising a
doped-type metal sulfide phosphor nanoparticle dispersed in water and/or
a hydrophilic solvent,wherein the doped-type metal sulfide phosphor
nanoparticle comprises a surface that is modified with a surface
modifier, the surface modifier being a compound represented by formula
[I]: HS-L-W Formula [I] wherein L represents a divalent linking group;
and W represents COOM or NH.sub.2, in which M represents a hydrogen atom,
an alkali metal atom, or NX.sub.4, in which X represents a hydrogen atom
or an alkyl group.