Research progress on rare earth up-conversion and near-infrared II luminescence in biological applications

Rare earth luminescence has attracted widespread attention for several decades, among which near-infrared (NIR) light-related up-conversion luminescence and NIR-II luminescence are widely used in the biomedical field. The NIR-related luminescence is widely studied due to the excellent performance, such as good biocompatibility, deep tissue penetration depth, low self-fluorescence and minimal light damage to organisms. In this review, we mainly introduce the mechanism for rare earth up-conversion luminescence, NIR-II luminescence and conclude their advantages compared with traditional luminescence. These excellent priorities provide the basis for NIR-related luminescence bioimaging in vivo. Additionally, we hilglight the scheme for the sensitive detection of substances in organisms and various methods for biological therapy. In spite of the existing research, it is outlined that NIR-related luminescence has great potential to be applied in different aspects, expanding perspectives and future challenges of research in related fields. Based on the current scientific achievements, this review can provide reference for research in the areas mentioned above, expand the research direction and arouse a broad interest in different disciplines to pay attention to rare earth luminescence.