金膜上CsPbBr3纳米晶超晶格增强双光子发射特性研究

Enhanced Two-photon Fluorescence of CsPbBr3 Nanocrystal Superlattice on Gold Films

摘要:

钙钛矿微纳结构双光子荧光在高分辨成像、光电转换等领域应用广泛,其中增强双光子荧光发射强度是提高器件性能的关键。与电介质基底相比,置于贵金属薄膜上的微纳结构由于等离激元的激发作用,能够有效增强线性及非线性光学响应。基于此,提出了在金膜上自组装CsPbBr₃纳米晶超晶格结构,与玻璃基底上样品相比,金膜上超晶格结构内部形成了更强的局域场增强。实验结果表明,其线性光致发光强度提高了约100%,而双光子发光强度得到了约16倍的显著提升。进一步通过改变泵浦光偏振方向可见,这种超晶格的双光子发射具有偏振依赖性,偏振角度在0°~360°范围内呈现四重对称性。研究结果表明,金膜上CsPbBr₃纳米晶超晶格是一种有效增强双光子发射的体系,这为构建高性能微纳非线性光子器件提供了新的可能性和优化思路。

Abstract:

Two-photon fluorescence emitted by micro/nanostructured perovskites has been widely applied in high-resolution imaging and photoelectric conversion. However, significantly enhancing the two-photon fluorescence emission intensity is essential for improving the performance of associated devices. Unlike dielectric substrates, the development of micro/nanostructures on precious metal films is effective for achieving enhanced linear and nonlinear optical responses owing to plasmon excitation. The results of this study showed that the optical response of superlattice structures grown on a gold film was stronger than that of samples grown on a glass substrate. Furthermore, experimental results showed that the linear photoluminescence intensity increased by approximately 100% and the two-photon luminescence intensity increased significantly by approximately 16 times. Furthermore, we confirmed a distinct polarization dependence of the two-photon emission of this superlattice by changing the polarization of the pump light, and that the polarization angle exhibited quadruple symmetry within the range of 0°~360°. These results indicated that growing a CsPbBr₃ nanocrystalline superlattice on a gold film is an effective strategy to achieve enhanced two-photon emission intensities. This study provides new possibilities and optimization ideas for constructing high-performance micro/nano-nonlinear photonic devices.