CsCu₂I₃ is an interesting new small band gap scintillator:

• It is nonhygroscopic and nontoxic, melts congruently, and has an extremely low afterglow, a density of 5.01 g/cm³, and an effective atomic number of 50.6.
• The mean emission at 560 nm (yellow) matches detection with an avalanche photo diode.
• A light yield of 36'000 photons/MeV and energy resolution of 4.82% were obtained.
• The scintillation proportionality is on par with that of SrI₂:Eu²⁺.
• CsCu₂I₃ shows self-trapped exciton emission at room temperature.
• The large Stokes shift of this emission ensures that this material is not sensitive to self-absorption.

This work was carried out in the groups of Prof. Dr. Pieter Dorenbos (TU Delft) and PD Dr. Karl Krämer (DCBP, Universität Bern).

References:

• J. J. van Blaaderen, L. A. van den Brekel, K. W. Krämer, P. Dorenbos;
  "Scintillation and Optical Characterization of CsCu₂I₃ Single Crystals from 10 to 400 K"
  Chem. Mater., 2023, 35(22), 9623-9631; doi:10.1021/acs.chemmater.3c01810.