Strain-engineered upconversion nanoparticles for power-tunable dynamic information encryption

Abstract

Strain-engineered upconversion nanoparticles with controlled Yb3+ doping exhibit power-tunable luminescence through lattice-strain–induced phase transitions. The strain modulation enables stepwise emission activation under varied excitation powers, achieving sequential information display. This single-wavelength excitation, power-gated approach provides a simple yet robust platform for dynamic and secure optical encryption.