新型光学微腔中CdSe@ZnS胶体量子点溶液光致荧光特性研究

Photoluminescence character of CdSe@ZnS colloidal quantum dots in new-type optical microcavity

通过共形生长薄膜的方法在图形衬底上设计和制备一种新型的光学微腔结构,可以同时实现对光子的限制和对量子点溶液的空间限制.应用这种微腔结构,研究CdSe@ZnS胶体量子点溶液在微腔光子限制作用下的光致荧光特性.通过实验研究分析,发现在微腔光子限制作用下,CdSe@ZnS胶体量子点溶液的荧光强度随着浓度的减小反而逐步增强,与常规容器中的量子点溶液随浓度发光强度变化规律相反;对于小尺寸的光学微腔而言,量子点溶液的发光峰位随浓度增大而出现了蓝移,与常规容器中的量子点溶液发光峰位随浓度变化规律有区别.这些差异体现了微腔作用下量子点溶液光致荧光的不同机制.设计的新型光学微腔产生的限制作用,对于量子点的发光机制产生了重要的影响.

A new‐type optical microcavity structure with distributed Bragg reflectors （DBRs）was fabricated .The DBRs were grown by conformal deposition method of silicon nitride and silicon oxide multilayers alternatively on patterned substrates .The optical microcavity could both realize the photon confinement and the space limitation of the quantum dots solution .The photoluminescence（PL）behavior of CdSe@ ZnS colloidal quantum dots in aqueous solution was studied in the optical microcavities .It could be observed that the PL intensity of the CdSe@ ZnS colloidal quantum dots in solution decreased with the concentration increasing in the new‐type optical microcavity .＆amp;nbsp;However ,in the common container ,the PL intensity of the CdSe@ ZnS colloidal quantum dots in aqueous solution in‐creased with the concentration increasing .When the diameter of the new‐type optical microcavity is small enough , the emission peak wavelength will blue shift with increasing quantum dots concentration .This is different from the shift behavior of the emission peak wavelength in the common container .It can be deduced that ,such different phenomena of the PL of the quantum dots in microcavity is due to the cavity confinement effect of the new‐type optical microcavities ,which deeply influences the PL mechanism of the CdSe@ ZnS colloidal quantum dots inside them .