期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2018
卷号：115
期号：26
页码：6632-6637
DOI：10.1073/pnas.1802064115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Optical upconversion that converts infrared light into visible light is of significant interest for broad applications in biomedicine, imaging, and displays. Conventional upconversion materials rely on nonlinear light-matter interactions, exhibit incidence-dependent efficiencies, and require high-power excitation. We report an infrared-to-visible upconversion strategy based on fully integrated microscale optoelectronic devices. These thin-film, ultraminiaturized devices realize near-infrared (∼810 nm) to visible [630 nm (red) or 590 nm (yellow)] upconversion that is linearly dependent on incoherent, low-power excitation, with a quantum yield of ∼1.5%. Additional features of this upconversion design include broadband absorption, wide-emission spectral tunability, and fast dynamics. Encapsulated, freestanding devices are transferred onto heterogeneous substrates and show desirable biocompatibilities within biological fluids and tissues. These microscale devices are implanted in behaving animals, with in vitro and in vivo experiments demonstrating their utility for optogenetic neuromodulation. This approach provides a versatile route to achieve upconversion throughout the entire visible spectral range at lower power and higher efficiency than has previously been possible.
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