Speaker
Description
Wavelength-shifting photon detection systems (PDS) are critical components in noble-liquid detectors for high-energy physics and dark-matter searches. The vacuum ultraviolet (VUV) scintillation from liquid argon (LAr, ~128 nm) and liquid xenon (LXe, ~175 nm) must be shifted to longer wavelengths to enable efficient detection with state-of-the-art photodetectors such as photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs). Organic wavelength shifters, most notably 1,1,4,4-tetraphenyl butadiene (TPB), suffer from photodegradation, self-absorption, and long-term reliability issues, motivating hybrid alternatives. Colloidal quantum-dot approaches (e.g., CsPbBr₃) have shown promise but face challenges with re-absorption from small Stokes shifts, environmental/binder compatibility, and cryogenic robustness.
In this study, we demonstrate Mn-doped phenethylammonium lead bromide (Mn:PEA₂PbBr₄) two dimensional perovskite thin films as highly efficient wavelength shifters. The key mechanism is host to dopant energy transfer: whereas undoped PEA₂PbBr₄ exhibits a small Stokes shift and therefore re-absorbs part of its own emission, Mn²⁺ incorporation converts this loss channel into a benefit by funneling re-absorbed energy to Mn centers and re-emitting at longer wavelength. The resulting large effective Stokes shift suppresses self-absorption, improves out-coupling, relaxes thickness constraints, and aligns the output with the peak quantum efficiency region of PMTs/SiPMs.
We fabricate uniform, large-area films by low-cost, scalable solution processing (spin and bar coating) on UV grade quartz substrates, enabling meter-scale PDS manufacturing without vacuum tooling. Solution processing further allows precise control of thickness and dopant loading, conformal coverage on complex geometries, and straightforward re-work/encapsulation when needed. We report absorption, transmittance and photoluminescence (PL) characterization and demonstrate stable operation at cryogenic temperatures relevant to LAr/LXe, with repeated cool-down and warm-up cycles confirming mechanical integrity (no visible cracking/delamination) and preserved emission.
These results establish Mn-doped 2D perovskite thin films as a process-friendly, cryo-compatible, and spectrally optimized wavelength-shifting platform, offering a clear pathway to scalable, meter-class PDS and broader wavelength-shifting applications in next generation noble-liquid detectors.
This project is funded by the European Union - Next Generation EU thorugh grant MUR PRIN 2022KJZSYB, CUP J53D23001780006.
| Speaker Confirmation | Yes |
|---|
