Abstract Here we report the production of high purity and crystallinity organic electronic material of NPB (N,N′-Di-[(1-naphthyl)-N,N′-diphenyl]-1,1′-biphenyl-4,4′-diamine (C44H32N2) through solution recrystallization within imidazolium based ionic liquids. When low purity NPB was recrystallized at 170 °C within C8MIM[TFSI], its purity was drastically improved from 82% to 99.92%. These recrystallized NPB crystals showed 0.040° FWHM (Full Width Half Maximum) of X-ray (1 1 1) diffraction peak. Such small FWHM angle indicates single-crystal like crystallinity. Initial NPB powder was dissolved at 100 °C and recrystallized at temperature above 110 °C. At higher temperature of 170 °C, a small number of bigger crystals were formed compared to those at 110 °C. This can be well explained by the classical nucleation and growth theory. Therefore, solution recrystallization process using ionic liquid might be promising for mass production of organic electronic materials by replacing the widely-used sublimation purification method.

中文翻译：

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基于咪唑鎓离子液体的 NPB 纯化和晶体生长

摘要 这里我们报道了 NPB (N,N'-Di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4' -二胺(C44H32N2)在咪唑基离子液体中通过溶液重结晶。当低纯度NPB在C8MIM[TFSI]中在170°C下重结晶时，其纯度从82%急剧提高到99.92%。这些重结晶的NPB晶体显示0.040°FWHM X 射线 (1 1 1) 衍射峰的 (Full Width half Maximum)。如此小的 FWHM 角表明类似单晶的结晶度。初始 NPB 粉末在 100 °C 下溶解并在高于 110 °C 的温度下重结晶。在更高的温度下在 170 °C 时，与 110 °C 时相比，形成了少量较大的晶体。这可以用经典的成核和生长理论很好地解释。因此，使用离子液体的溶液重结晶过程可能取代广泛使用的升华纯化方法，有望用于有机电子材料的大规模生产。