Lead-halide perovskites are attractive optical materials since they combine strong excitonic response, fast emission, and facile solution processing [1]. These features also make them promising scintillators, namely materials that convert high-energy radiation into detectable optical signals for radiation detection, medical imaging, and related photonic technologies. In such systems, both light yield and temporal response are critical, yet they are usually constrained by the intrinsic radiative and non-radiative pathways of the emitting medium. Nanophotonic approaches offer a route to overcome these limitations by modifying how the optical environment interacts with excited states generated under ionizing radiation.

In scintillators, nanophotonic concepts have so far been explored mainly in the weak-coupling regime, where the optical environment modifies the local density of optical states and accelerates radiative recombination through the Purcell effect [2-4]. In this regime, emission can be made faster and brighter, but the emitter and the optical mode remain distinct. A more advanced regime is strong light-matter coupling, in which coherent interaction between excitonic and plasmonic states leads to the formation of hybrid light-matter states with new spectral and dynamical properties [5-7]. Here, we show that perovskite nanoplasmonic scintillators can evolve continuously from Purcell-enhanced emission to strong light-matter coupling.

Our first platform is based on CsPbBr₃ nanocrystals embedded in a transparent PDMS matrix and coupled to plasmonic Ag nanoparticles. These composites behave as Purcell-engineered bulk scintillators, demonstrating that nanoplasmonic rate engineering is not restricted to ultrathin films. In 5 mm-thick composites, we observed up to a 4.2-fold decay-rate enhancement and a 2.1-fold increase in light yield under ²⁴¹Am γ-excitation [3]. This result is important because it shows that plasmonically modified scintillation can be scaled to bulk architectures relevant to practical radiation-detection formats, rather than remaining limited to near-surface or thin-layer configurations.

We then move beyond the weak-coupling regime and demonstrate exciton-plasmon strong coupling in bulk CsPbBr₃ nanoplatelet composites embedded with Ag nanocubes. By tuning nanocube dimensions and temperature, we achieve resonance alignment between excitonic and plasmonic modes and observe Rabi splitting, mode anticrossing, and polaritonic dispersion in angle-resolved photoluminescence. The normalized coupling ratios reach  g/ω_x = ( 0.32 ± 0.01 ) in photoluminescence and ( 0.36 ± 0.01 ) in radioluminescence [5]. These results show that hybrid light-matter states can be formed directly in a bulk scintillating composite under conditions relevant to ionizing-radiation excitation, opening a route toward bulk polaritonic scintillators.

To complement the experiments, we develop a quantum-optical framework for near-infrared nanoplasmonic scintillators [8]. The near-infrared is particularly relevant because lower-band-gap scintillators can, in principle, generate more electron-hole pairs per unit of deposited energy, while conductive platforms such as ITO and graphene can support narrower, lower-loss optical modes than conventional noble-metal antennas [9,10]. Our calculations show that strong-coupling signatures are jointly governed by emitter dephasing and antenna linewidth, with narrow-band emitters and spectrally narrow antennas providing the most favorable conditions. This defines a strategy for scintillators spanning the visible and near-infrared and shows that the concept is not restricted to a single emission window.

Overall, these results establish perovskite nanoplasmonic scintillators as a materials platform in which emission can be engineered across coupling regimes, from rate-enhanced scintillation to polaritonic hybridization. Such behavior may be of future interest for radiation detection, imaging, nuclear batteries, and memory-related radiation-encoding concepts.