A crystal material represented by a general formula (1):
(Gd.sub.1-x-y-zLa.sub.xME.sub.yRE.sub.z).sub.2MM.sub.2O.sub.7   (1),
where ME is at least one selected from Y, Yb, Sc, and Lu; RE is Ce or Pr; MM is at least one selected from Si and Ge; and ranges of x, y, and z are represented by the following (i): (i) 0.0≦x+y+z<1.0, 0.05≦x+z<1.0, 0.0≦y<1.0, and 0.0001≦z<0.05 (where, when RE is Ce, y=0 is an exception).

The present invention relates to a phosphor, a method for preparing the phosphor, an optoelectronic component, and a method for producing the optoelectronic component. The phosphor has the following general formula: La.sub.3(1x)Ga.sub.1yGe.sub.5(1z)O.sub.16: 3xA.sup.3+, yCr.sup.3+, 5zB.sup.4+, where x, y, and z do not equal to 0 simultaneously; A represents at least one of Gd and Yb; B represents at least one of Sn, Nb, and Ta. For the phosphor, its emission spectrum is within a red visible light region and a near-infrared region when excited by blue visible light, purple visible light or ultraviolet light; and it has a wide reflection spectrum and a high radiant flux. Therefore, it can be used in optoelectronic components such as LEDs to meet requirements of current medical testing, food composition analysis, security cameras, iris/facial recognition, virtual reality, gaming notebook and light detection and ranging applications.