Crystalline superfine particles capable of emitting light depending upon a
time-rate-of-change of a stress and controlled in grain size in the range
from 5 nm to 100 nm are complexed with another material such as resin.
The crystalline superfine particles are manufactured by using aggregates
of molecules, i.e. inverted micelles, which orient hydrophilic groups of
surfactant molecules inward and hydrophobic groups outward in a nonpolar
solvent and which contain metal ions of a metal for forming the
crystalline superfine particles dissolved in water inside the inverted
micelles. Alternatively, they are manufactured by using inverted micelles
enveloping precursor superfine particles, in which precursor superfine
particles are enveloped in water inside the inverted micelles. The
crystalline superfine particles are excellent in dispersibility in
another material to be complexed, enhanced in emission efficiency and
usable to make a transparent stress emission material. The complex
material obtained is used to manufacture artificial light-emitting hair
structures, artificial light-emitting skin, artificial light-emitting
bodies, artificial light-emitting fabrics, and others.