Sun Tianying, Ai Fujin, Zhu Guangyu, Wang Feng
Department Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China.
City Universities of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.
Chem Asian J. 2018 Feb 16;13(4):373-385. doi: 10.1002/asia.201701660. Epub 2018 Jan 17.
Photon upconversion that is characterized by high-energy photon emission followed by lower-energy excitation has been conventionally studied in bulk materials for several decades. This unique nonlinear luminescence process has become a subject of great attention since 2000 when upconverted emission was demonstrated in nanostructured crystals. In comparison with their bulk counterparts, nanostructured materials provide more room for optical fine-tuning by allowing flexible compositional integration and structural engineering. Moreover, the high colloidal stability of nanoparticles coupled with high amenability to surface functionalization opens up a number of new applications for upconversion, especially in the fields of biology and life science. In this focus review, we discuss recent developments in upconversion materials through nanostructural design and review emerging biomedical applications that involve these nanostructured upconversion materials. We also attempt to highlight challenging problems of these nanomaterials that constrain further progress in utilizing upconversion processes.
几十年来，人们一直在常规地研究体材料中的光子上转换现象，其特征是先发射高能光子，然后是低能激发。自2000年在纳米结构晶体中证明上转换发射以来，这种独特的非线性发光过程已成为备受关注的课题。与体材料相比，纳米结构材料通过灵活的成分整合和结构工程，为光学微调提供了更多空间。此外，纳米颗粒的高胶体稳定性以及对表面功能化的高适应性，为上转换开辟了许多新的应用领域，尤其是在生物学和生命科学领域。在这篇重点综述中，我们讨论了通过纳米结构设计实现的上转换材料的最新进展，并综述了涉及这些纳米结构上转换材料的新兴生物医学应用。我们还试图强调这些纳米材料存在的具有挑战性的问题，这些问题限制了上转换过程在实际应用中的进一步发展。
