Correction to: Activators Confined Upconversion Nanoprobe with Near-Unity Förster Resonance Energy Transfer Efficiency for Ultrasensitive Detection (ACS Appl. Mater. Interfaces (2022) 14:17 (19826-19835) DOI: 10.1021/acsami.2c00604)

For additional information about our published article, we analyzed the detailed test procedure of the upconversion luminescence decay curves presented in Figure 5e. We also reprepared the NaYbF4@NaYF₄:Yb³⁺,Er³⁺@SiO₂@NR nanoprobe and measured the luminescence decay curves to prove the authenticity and validity of the nanoprobe's FRET detection capacity. This will help readers understand the lifetime data calculated from luminescence decay curves and avoid misunderstandings. This supplemental information does not affect the final results and conclusions of the paper. Upconversion Luminescence Decay Curves Measurement. The primary technique used in luminescence lifetime measurements is time-correlated single-photon counting (TCSPC). This approach employs a narrowly pulsed laser as the excitation source and records the time taken for a single fluorescence photon emitted by the sample to reach the detector. By repeating this process numerous times, sufficient statistical data are collected to reconstruct the luminescence decay profile. The resulting data are then fitted to obtain the luminescence lifetime value. In the luminescence lifetime measurements reported in our published article, due to the laboratory constraints at the time, we utilized a self-constructed test platform to acquire the luminescence decay curves of the probe. Specifically, an external pulse generator (GWINSTEK AFG-200) was used to modulate a continuous-wave 980 nm laser into a pulsed excitation source. The emitted luminescence from the probe sample was then detected by a single photon counting module (DCS200PC, Zolix Instruments), and the resulting decay curves were recorded. These curves were analyzed by fitting to an exponential decay model to determine the luminescence lifetime values. The measured lifetime data in Figure 5e of our published article were acquired by incrementally adding a NO2 − solution to the same nanoprobe sample. For the reason that the noise points of the curves in Figure 5e of our published article are similar, we deduce that the similarity in decay curve noise points was attributed to potential debugging inconsistencies among devices used in the luminescence lifetime test. A detailed examination of raw data reveals that despite the similar analogous noise features the distribution of data points exhibited discernible divergence upon close inspection. We regret the confusion arising from the luminescence lifetime data presented in Figure 5e of our published article. To validate the authenticity and reliability of these data, we have reprepared the NaYbF4@NaYF₄:Yb³⁺,Er³⁺@SiO₂@NR nanoprobe on February 21, 2025. The luminescence lifetimes of the nanoprobe were characterized using a steady-state and transient spectrofluorometer (FLS 1000, Edinburgh Instruments Ltd.) with an external 980 nm semiconductor laser excitation source (Changchun New Industries Optoelectronics Tech. Co. Ltd.), which represents a widely adopted lifetimetesting platform in high-impact academic publications. (Nature Communications, 2022, 13(1), 5927; Nature Photonics, 2024, 18(5), 440−449). The transmission electron microscopy (TEM) image of the reprepared NaYbF₄@NaYF₄:Yb³⁺,Er³⁺@SiO₂ @NR nanoprobe is shown in Figure C1a, showing an average diameter of 32 nm. Figure C1b presents the luminescence decay curves of NaYbF₄@NaYF₄:Yb³⁺,Er³⁺ and NaYbF₄@NaYF₄:Yb³⁺,Er³⁺@SiO₂@NR nanoparticles recorded at 545 nm. A significant reduction in the lifetime of the 4S3/2 state of Er3+ from 953 to 110 μs was observed, corresponding to a Förster resonance energy transfer (FRET) efficiency of 88.5% calculated using the equation E = 1 DA D , where τDA and τD represent the lifetime of the donor in the presence and absence of the acceptor, respectively. Additionally, Figure C2 illustrates the response of the 4S3/2 state of Er3+ lifetime to varying NO2 − concentration. The lifetime values increase from 110 to 650 s as the NO2 − concentration is elevated from 0 to 60 μg/mL, confirming the efficient FRET sensing process. (Figure presented).