1：Experimental Design and Method Selection:

Designed four types of NaYF4-based UCNP with different core-shell architectures (AC, AC-IS, IC-TS, IC-TYS) co-doped with Yb3+ and Tm3+ ions. Used ligand exchange to attach DBD-6 dye to UCNP surface. Employed steady-state and time-resolved luminescence measurements to study RET.

2：Sample Selection and Data Sources:

Synthesized UCNP using Therminol?66 protocol. DBD-6 dye was synthesized and characterized. Samples were prepared in cyclohexane.

3：List of Experimental Equipment and Materials:

Equipment includes pulsed Nd:YAG laser with OPO system, intensified CCD camera coupled to spectrograph, UV/Vis spectrometer, TEM, XRD instrument. Materials include rare earth chlorides, oleic acid, ammonium fluoride, cyclohexane, MOPS buffer, ethanol, sodium hydroxide, Therminol?66, and chemicals for DBD-6 synthesis.

4：Experimental Procedures and Operational Workflow:

UCNP synthesis involved heating metal chlorides with OA and Therminol?66, adding sodium oleate and NH4F, heating to 320°C, purification. Core-shell synthesis involved adding shell precursor. Ligand exchange by incubating UCNP with DBD-6 in cyclohexane. Luminescence measurements at 976 nm excitation, recording spectra and decay kinetics. UV/Vis absorption measurements for dye characterization. TEM and XRD for structural analysis.

5：Data Analysis Methods:

Used biexponential fitting for decay kinetics, calculated RET efficiency using lifetime changes, spectral overlap integrals, and F?rster distances. Statistical analysis of band ratios and decay times.