Controlling surface reactions of CdS nanocrystals: photoluminescence activation, photoetching and photostability under light irradiation
Controlling surface reactions of CdS nanocrystals: photoluminescence activation, photoetching and photostability under light irradiation
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DOI：
10.1088/0957-4484/18/46/465702
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发表时间：
2007-11
期刊：
影响因子：
3.5
通讯作者：
Keiichi Sato;S. Kojima;S. Hattori;T. Chiba;Keiko Ueda-Sarson;T. Torimoto;Y. Tachibana;S. Kuwabata
中科院分区：
文献类型：
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作者：
Keiichi Sato;S. Kojima;S. Hattori;T. Chiba;Keiko Ueda-Sarson;T. Torimoto;Y. Tachibana;S. Kuwabata
研究了CdS纳米晶在光照下的光致发光增强、光刻和光稳定性。强的光致发光纳米晶体时，得到的水溶液中，在pH = 11，在氧气的存在下，弱的光激发。在XPS测量的支持下，提出了以下光活化机制：由于在氧气存在下的缓慢光腐蚀，Cd 2+离子从CdS表面释放，并且在碱性条件下在CdS表面上形成Cd-OH键，去除表面陷阱态。确定了辐照光的波长和溶液的pH值作为纳米纤维表面改性的关键参数。对于稳定性测量，在非极性溶剂中用铵盐萃取纳米晶体。在非极性相的纳米晶体的光致发光量子产率达到约30%。所提取的纳米晶体即使在紫外光照射下也非常稳定，并且光致发光强度保持了几个月。
Photoluminescence enhancement, photoetching and photostability of CdS nanocrystals were investigated under light irradiation. Strongly photoluminescent nanocrystals were obtained when the nanocrystal was weakly photoexcited in an aqueous solution at pH = 11 in the presence of oxygen. With the support of XPS measurements, the following photoactivation mechanism is proposed: Cd2+ ions are released from the CdS surface owing to slow photocorrosion in the presence of oxygen, and Cd–OH bond formation occurs on the CdS surface under the alkaline conditions, removing the surface trap states. The wavelength of the irradiating light and the pH of the solution were determined as key parameters for nanocrystal surface modification. For the stability measurements the nanocrystals were extracted with an ammonium salt in a non-polar solvent. The photoluminescence quantum yield for the nanocrystals in the non-polar phase reached approximately 30%. The extracted nanocrystals were remarkably stable even under UV light irradiation, and the photoluminescence intensity was maintained for several months.