biostudies-literatureJiang ZN/ANational Natural Science Foundation of ChinaNational Natural Science Foundation of China (National Science Foundation of China)827https://www.ebi.ac.uk/biostudies/studies/S-EPMC9929054biostudies-literatureUnknown14(1)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 Nd³⁺ and Ho³⁺ 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 (Er³⁺, Ho³⁺, Pr³⁺, and Tm³⁺). Transient spectra confirm the directional energy transfer from sensitizNature communicationsUltra-wideband-responsive photon conversion through co-sensitization in lanthanide nanocrystals.PMC992905481971704Li WJiang ZYang ZQiu HHe LChen XYu XfalseUltra-wideband-responsive photon conversion through co-sensitization in lanthanide nanocrystals.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 Nd³⁺ and Ho³⁺ 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 (Er³⁺, Ho³⁺, Pr³⁺, and Tm³⁺). Transient spectra confirm the directional energy transfer from sensitiz2023-01-01T00:00:00Z2023 Feb2025-04-18T13:37:51.783Z2025-04-04T11:16:32.92ZS-EPMC99290543678823910.1038/s41467-023-36510-3