Annealing of tris(8-hydroxyquinoline) gallium (Gaq₃) film at various temperatures in dry N₂ atmosphere has shown the existences of four different phases of molecular aggregations before the burning out of the film at about 310 °C. The first three phases, up to 235 °C, are amorphous molecular aggregations, while the fourth one at 255 °C is a crystalline structure, very likely α-polymorph. The photoluminescence (PL) intensity was increased to about five times greater than that of the pristine film at 235 °C, while the PL peak was blue shifted consistently. Although a small contribution of Rayleigh scattering cannot be excluded at high temperatures when crystallites appear, the PL blueshift was mainly attributed to the nanostructured molecular aggregations followed by enhanced PL intensity. These new findings can be a common characteristic of organometallic complexes at varied annealing temperatures. The presented results open a new route of fabricating highly emissive thin films of amorphous nanostructure, which are specifically important for organic light emitting diode (OLED) based displays.

三（8-羟基喹啉）镓（Gaq ₃）薄膜在不同温度下于干燥N _2中的退火大气表明在约310°C的温度下烧掉薄膜之前，存在四个不同阶段的分子聚集。前三个相（最高235°C）是非晶态分子聚集体，而第四个相在255°C下则是晶体结构，很可能是α-多晶型物。在235°C时，光致发光（PL）强度增加到比原始膜大5倍左右，而PL峰则呈蓝移。尽管在出现微晶时无法在高温下排除瑞利散射的一小部分贡献，但PL蓝移主要归因于纳米结构分子聚集，其后是PL强度增强。这些新发现可能是有机金属配合物在不同退火温度下的共同特征。