High‐Capacity Upconversion Wavelength and Lifetime Binary Encoding for Multiplexed Biodetection

Abstract Optical multiplexing plays an important role in fields ranging from advanced biological assays to security. However, conventional codes based on fluorescent color and intensity are limited to spectral overlap and background interference. Herein, we present a new multiplexing concept by manipulating the luminescence emission color and decay lifetimes of upconversion nanoparticles (τ λ ‐UCNPs) separately for the first time through designing the core/multi‐shell structure and controlled energy relay method. This new color/lifetime binary strategy exhibits exponentially scalable encoding capacity (>10 5 ), three orders of magnitudes higher than that of conventional color/intensity way. The strategy enables the multiplexed detection of human papilloma virus (HPV) subtypes in patient samples and robust anti‐counterfeiting. This work opens new opportunities for optical multiplexing with luminescent materials.