Ultra-wideband-responsive photon conversion through co-sensitization in lanthanide nanocrystals.

Jiang, Zhao; He, Liangrui; Yang, Zhiwen; Qiu, Huibin; Chen, Xiaoyuan; Yu, Xujiang; Li, Wanwan · Nat Commun · 2023

basic_science · Level V

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Abstract

Distinctive upconversion or downshifting of lanthanide nanocrystals holds promise for biomedical and photonic applications. However, either process requires high-energy lasers at discrete wavelengths for excitation. Here we demonstrate that co-sensitization can break this limitation with ultrawide excitation bands. We achieve co-sensitization by employing Nd<sup>3+</sup> and Ho<sup>3+</sup> as the co-sensitizers with complementary absorptions from the ultraviolet to infrared region. Symmetric penta-layer core-shell nanostructure enables tunable fluorescence in the visible and the second near-infrared window when incorporating different activators (Er<sup>3+</sup>, Ho<sup>3+</sup>, Pr<sup>3+</sup>, and Tm<sup>3+</sup>). Transient spectra confirm the directional energy transfer from sensitizers to activators through the bridge of Yb<sup>3+</sup>. We validate the features of the nanocrystals for low-powered white light-emitting diode-mediated whole-body angiography of mice with a signal-to-noise ratio of 12.3 and excitation-regulated encryption. This co-sensitization strategy paves a new way in lanthanide nanocrystals for multidirectional photon conversion manipulation and excitation-bandwidth-regulated fluorescence applications.