Smart phosphor with neuromorphic behaviors enabling full-photoluminescent Write and Read for all-optical physical reservoir computing

Abstract

The unprecedented growth in information across diverse media drives an urgent need for multifunctional materials and devices beyond conventional electrical paradigms. This work explores all-optical information processing based on photoluminescence functions using smart phosphor. The developed composite phosphor of mixed-halide perovskite embedded macroporous Y₂O₃:Eu³⁺ exhibits adaptive photoluminescence variations with neuromorphic characteristics. Theoretical simulations reveal interface-mediated halogen migration processes with progressively evolving energy barriers, underpinning the neuron-like photoluminescence property variations. The system enables full photoluminescence-based Write and Read functionalities for all-optical neuromorphic computing, achieving 4-bit binary sequence discrimination as physical reservoirs. It further demonstrates potential in photoluminescence-based fingerprint authentication with 94.4% accuracy. This work advances smart phosphor as an alternative approach to neuromorphic computing with optical-stimuli and optical-output. It also opens avenues for designing function-oriented phosphor materials with tailored properties for information science and artificial intelligence applications.

Fig. 1. PL-based Write and Read mechanisms of MHPe@MYE.

a Schematic of a biological synapse. Created in BioRender. Lao, X. (2025) https://BioRender.com/syuovcp. b Schematic illustration of the MHPe@MYE porous structure. Created in BioRender. Lao, X. (2025) https://BioRender.com/at18ev9. c PL properties variation of MHPe@MYE showing PL properties changes during Write and Read operations, with tagged points (1–5) corresponding to specific PL states. d Schematic illustrations of the microscopic mechanisms at points 1–5 in (c). e Time-resolved PL intensity mapping of MHPe@MYE upon continuous 360 nm laser excitation. The tagged area by blue and pink dash line represents PL signal from MHPe and MYE, respectively. (Color bar: blue to red represents 1000 to 30020 in arb. units). f Inert PL dynamics of MHPe@MYE under Read excitation. g PL dynamics featuring both Read and Write processes.

Fig. 2. Theoretical insights into the adaptive halogen migration behaviors of MHPe@MYE.

a Electronic band structure of perfect CPB, perfect CPBC, and v-CPBC. The green, red, and blue regions indicate the projected contributions from Pb-, Br-, and Cl-orbitals, respectively. The dot line cycles the emergent shallow defect level. b Illustrative scheme of the adsorption site of Br/Cl on Y₂O₃ surface and c the corresponding $\gamma$. d CCD diagram of Br- and Cl-adsorption on Y₂O₃ surface, where red and blue region indicates electron accumulation and depletion, respectively. e Schematic illustration of Br migration pathway from MYE-surface adsorption and interface to subsurface and inner CPBC (or CPB) lattice. f The NEB energy landscape of the migration processes in CPBC and CPB.

Fig. 3. Neuromorphic behaviors in the PL variation process of MHPe@MYE.

a PL dynamics of MHPe (upper) featuring Write PL variation and Read dark recovery process, and the PL dynamics of Eu³⁺ in MYE (lower) during the same process using programmed 365 nm LED as excitation light spikes. b Stimuli-dependent synaptic behaviors of MHPe@MYE under different spike parameters of λ_em, λ_ex, I_ex, and f. Error bars are s.d. from four measurements. cx-dependent LTM features of MHPe@MYE, error bars represent s.d. of five measurements. Inset shows the definitions of N_n, N_t, N_x, I_t, and I_x in the PL dynamics (e.g., x = 30 s). d Fitting curve of PPF indices of MHPe@MYE with s.d. error bars from four measurements. e PL dynamics during formation of STP and LTP. Inset shows the reproducibility of STP (blue) and LTP (red) at the early stages of PL dynamics. f PL dynamics during the decay of STP and LTP, and the corresponding fitting curves. Inset displays s.d. statistical analyses of the fitted time constants across eight measurements.

Fig. 4. Potential application of MHPe@MYE as all-optical physical reservoir.

a Schematic representation of 4-bit binary code 1011 encoding through Write and Read light pulse waveforms. b Characteristic Read PL dynamics of MHPe@MYE of 16 binary sequences, with SMP locations indicated in the inset. c Representations of 1100, 0110, 1110, and 1111 Write waveforms used as binary sequences. d Statistical quantification of PL readout distributions at SMP1 and SMP2 of all 16 binary sequences, demonstrating code-specific PL signatures with small s.d. error margins from eight measurements. e 2D feature space projection of dual-feature PL readouts based on eight measurements, showing effective separation of all 4-bit sequence. f Schematic illustrations of SOCOFing fingerprint data acquisition and preprocessing from UV camera imaging, and light pulse conversion to full-PL-based information processing through the MHPe@MYE physical reservoir. Scheme was created in BioRender. Lao, X. (2025) https://BioRender.com/qgctjin. g Software-based offline ANN training of the processed results for distinguishing authentic and counterfeit fingerprints. h Training records of Dev1 and Dev2.