硫酸根离子对草酸-硫酸混合酸中制备的多孔阳极氧化铝光致发光特性的影响

采用电化学阳极氧化法,分别在草酸、硫酸及两者不同浓度比的混合酸中制备了AAO薄膜样品,并分别观察了在250,296 nm光激发下的光致发光(PL)特性。结果表明:草酸和混合酸中制备的AAO薄膜,在250~550 nm范围内的光致发光与不同存在或分布形式的草酸杂质形成的发光中心相关。硫酸根离子对混合酸中制备的AAO薄膜的PL特性有很大影响,随硫酸根离子浓度的增加发光峰位逐渐蓝移。分析了出现上述实验现象的原因。

The Effects of Sulfuric Ions on Photoluminescence of Porous Anodic Aluminum Oxide Membranes Prepared in Solution of Sulfuric and Oxalic Acid

Anodic aluminum oxide (AAO) samples have been prepared by using electrochemical anodizing technique in oxalic acid,sulfuric acid and oxalic/sulfuric mixture acid with different concentrations, respectively, of which photoluminescence (PL) properties are studied under an excitation of 250 and 296 nm, respectively. The measurement shows that the AAO film samples prepared in oxalic acid and the mixture electrolyte, respectively, have the PL bands in the wavelength range of 250~550 nm. The sulfuric ions have a strong effect on the PL bands, and with increasing sulfuric ions content, the PL peak positions of the AAO film samples have a gradually blueshift, which is from 410 nm to 345 nm and 410 nm to 385 nm with excitation of 250 nm and 296 nm, respectively. However, the PL intensities of the AAO film samples increase with increa-sing sulfuric acid content under the excitation of 250 nm and decrease under the excitation of 296 nm. The PL of AAO films would originate from the centers transformed from the oxalic impurities with different existing or distributing forms in AAO films. The reasons for the experimental phenomena are discussed.