溶胶-凝胶制备ZnO-SiO2复合膜的量子效应和上转换发光

采用溶胶-凝胶技术在玻璃衬底上制备了ZnO薄膜和ZnO-SiO₂复合膜.原子力显微镜照片显示ZnO薄膜具有球状纳米晶粒；可见光-紫外透射光谱表明ZnO-SiO₂复合膜在可见光区的透过率大约是85%，透过率从330 nm开始下降，到290 nm附近降为零.由于量子效应，吸收边出现明显的蓝移.在室温下用不同波长的光激发ZnO-SiO₂复合膜，光致发光谱显示ZnO-SiO₂复合膜对应于激子发射的290 nm附近的紫外发光峰与透射谱所显示的吸收边位置一致，没有出现斯托克斯红移.同时，ZnO-SiO₂复合膜出现了双光子和三光子吸收现象和上转换发光现象. 关键词： 2')" href="#">ZnO-SiO₂ 量子效应 双光子和三光子吸收 上转换发光

Quantum effect and up-conversion luminescence of ZnO-SiO2 composite films synthesized by sol-gel technique

ZnO thin films and ZnO SiO₂ composite films were deposited on glass substrates by sol gel method. Atomic force microscope images showed that ZnO nano particles havd spherical shape of relativly small size. The ultraviolet visible transmittance spectra showed that the transmittance of ZnO SiO₂ composite film is about 85% in visible range and the transmittance begins to drop at about 330 nm and reaches zero around 290 nm. Due to quantum effect, the absorption edge has an obvious blue shift. Photoluminescence spectra measurement indicated that ZnO SiO₂ composite film excited by a Xe lamp with different wavelength has a UV emission around 290 nm coming from combination of free excitons, which is in agreement with the ultraviolet visible transmittance measurement result. Meanwhile, two photon and three photon absorption and up conversion luminescence were observed in the ZnO SiO₂ composite film.