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The photoluminescence (PL) spectra of C60 single crystals grown under double temperature gradient (DTG) and single temperature gradient (STG) techniques were investigated at room temperature. The results show that the PL emission intensity increases first and then decreases with increasing illuminated power density for the C60 single crystals grown by both DTG and STG techniques. Furthermore, one main peak with a shoulder peak can be clearly distinguished at low illumination, while only one main peak without the shoulder peak can be seen at high illumination. The main peak undergoes a continuous blue shift and broadening with the increase of illuminated power density. The difference of PL emission energy at the same illumination density of DTG and STG samples may correlated with the degree of both the orientational disorder of C60 molecule and lattice perfectness. The Laue diffraction patterns show that the DTG sample has stronger strains and poorer crystalline quality than the STG sample.

α-LiIO3 single crystals were grown by the aqueous solution method in a Chinese scientific return-satellite. The morphology of the crystals grown in space are similar to that of earth-grown crystals. It is found that the growth rates of the positive and negative sides of the space-grown crystals are almost the same. The perfection of both crystals grown in space and on earth was examined.