Oxygen-Independent Photoactivation of Kinetically Trapped Persistent Room-Temperature Phosphorescence State for Smart Cold-Chain Monitoring

• • Afterglow duration exceeds 70 s by naked eye, enabling practical visual readout without instrumentation; this threshold is critical for field-deployable cold-chain indicators where rapid, equipment-free verification is required. • • Activated RTP state persists ~5 h at 25°C versus ~72 h at 4°C, a 14.4-fold kinetic difference; this temperature-dependent lifetime provides a cumulative thermal exposure metric, essential for monitoring perishable goods during transport. • • Relative RTP intensity loss >84.2% after 3 h at 25°C compared to 4°C, establishing a quantitative threshold for irreversible temperature abuse detection; such sensitivity allows early intervention in cold-chain logistics. • • Photoactivation occurs under both aerobic and anaerobic conditions, eliminating oxygen sensitivity that plagues conventional RTP turn-on mechanisms; this robustness ensures reliable performance in sealed packaging where oxygen levels vary.