Surface modification of Al₂O₃ powders, prepared using reproducible sol-gel synthetic route with small colorless organic molecules, induces charge transfer complex formation and the appearance of absorption in the visible spectral region. Comprehensive microstructural characterization involving transmission electron microscopy, X-ray diffraction analysis, and nitrogen adsorption–desorption isotherms, revealed that γ-crystalline alumina powders consist of mesoporous particles in the size range from 0.1 to 0.3 μm, with specific surface area of 54.8 m²/g, and pore radius between 3 and 4 nm. The attachment of catecholate-type of ligands (catechol, caffeic acid, gallic acid, dopamine and 2,3-dihydroxy naphthalene), salicylate-type of ligands (salicylic acid and 5-amino salicylic acid), and ascorbic acid, to the surface such γ-Al₂O₃ particles leads to the formation of colored powders and activates their absorption in visible-light spectral region. To the best of our knowledge, similar transformation of an insulator (Al₂O₃), with the band gap energy of 8.7 eV, into a semiconductor-like hybrid material with tunable optical properties has not been reported in the literature before. The density functional theory (DFT) calculations with periodic boundary conditions were performed in order to estimate the energy gaps of various inorganic/organic hybrids. The calculated values compare well with the experimental data. The good agreement between the calculated and experimentally determined band gaps was found, thus demonstrating predictive ability of the theory when proper model is used.

使用可重现的溶胶-凝胶合成路线和小的无色有机分子进行制备的Al ₂ O ₃粉末的表面改性，会导致电荷转移络合物的形成以及在可见光谱区域的吸收现象。全面的微观结构表征，包括透射电子显微镜，X射线衍射分析和氮吸附-解吸等温线，发现γ晶氧化铝粉末由介孔颗粒组成，介孔颗粒的尺寸范围为0.1至0.3μm，比表面积为54.8 m ²/ g，孔半径在3-4 nm之间。邻苯二酚型配体（邻苯二酚，咖啡酸，没食子酸，多巴胺和2,3-二羟基萘），水杨酸酯型配体（水杨酸和5-氨基水杨酸）和抗坏血酸的附着这样的γ-Al ₂ ö ₃颗粒导致着色粉末的形成和激活可见光光谱区的吸收。据我们所知，绝缘子（Al ₂ O ₃），带隙能量为8.7 eV，进入具有可调光学特性的类半导体混合材料之前从未有文献报道过。为了估计各种无机/有机杂化物的能隙，进行了具有周期性边界条件的密度泛函理论（DFT）计算。计算值与实验数据很好地比较。在计算得出的带隙和实验确定的带隙之间找到了很好的一致性，从而证明了使用适当模型时该理论的预测能力。