# Urea‐Formaldehyde Resin Confined Silicon Nanodots Composites: High‐Performance and Ultralong Persistent Luminescence for Dynamic AI Information Encryption

## TL;DR

This paper introduces a new material combining silicon nanodots and a resin matrix to achieve both high light efficiency and long-lasting glow, useful for AI-based data encryption.

## Contribution

A dual-functional matrix design that simultaneously achieves high phosphorescence quantum yield and ultralong afterglow in silicon nanodots.

## Key findings

- The material achieves a phosphorescence quantum yield of 81.04% and an afterglow lifetime of 3.44 seconds.
- The afterglow can be tuned to deep-red wavelengths (702 nm) through energy transfer.
- The material enables dynamic AI-assisted information encryption using tunable luminescent properties.

## Abstract

Persistent luminescence materials typically encounter an intrinsic trade‐off between high phosphorescence quantum yield (PhQY) and ultralong phosphorescence lifetime. To overcome this limitation, we propose a strategy that immobilizes silicon nanodots (SiNDs) within a dual‐functional composite matrix. The SiNDs efficiently generate abundant triplet excitons through intersystem crossing processes and simultaneously exhibit high PhQYs. Importantly, the urea‐paraformaldehyde‐derived matrix provides both the spatial confinement of molten urea and the extensive hydrogen‐bonding network of the urea‐formaldehyde resin. This synergistic configuration effectively immobilizes triplet excitons and suppresses nonradiative decay pathways. As a result, the material exhibits a remarkable PhQY of 81.04% together with an ultralong afterglow lifetime of 3.44 s. Furthermore, the energy transfer strategy further extends the persistent afterglow into the deep‐red region (702 nm). Leveraging the tunable afterglow colors and time‐resolved luminescent characteristics, an artificial intelligence‐assisted information encryption system was successfully developed. This work demonstrates that integrating SiNDs with a dual‐characteristic matrix provides a promising approach to concurrently achieving high PhQYs and ultralong lifetimes, thereby broadening the application scope of ultralong‐afterglow materials and guiding the rational design of next‐generation persistent luminescence materials.

Schematic illustration of SiNDs composite materials synthesis and its internal photophysical process mechanism. And an AI‐assisted dynamic information encryption process.