Melt-Processable and Thermally Driven Self-Healing Luminescent Cu(I) Hybrid Metal Halides

Despite the fascinating optical and electronic properties
of emerging
Cu(I) halides, their high melting points, irreversible decomposition,
and intrinsic instability have hindered optoelectronic applications.
Here, we designed novel Cu(I) halides, namely C12H28NCuCl2 and C20H48N2Cu4Cl6, with significantly lower melting points
(86 and 122 °C), enabling remarkable moldability. Intriguingly,
this investigation demonstrates that the aging and luminescence-quenching
phenomena observed in C12H28NCuCl2 and C20H48N2Cu4Cl6 crystals resulting from the air oxidation can be effectively
reversed through controlled heat treatment. The resulting C12H28NCuCl2 and C20H48N2Cu4Cl6 crystals exhibit broadband emission
with photoluminescence quantum yields of 74.78% and 46.52%, respectively.
Furthermore, C12H28NCuCl2 displays
bright radioluminescence, showing an internal X-ray to light conversion
efficiency of 36 506 photons/MeV under steady state X-ray illumination.
The inherent melt processability of these materials empowers their
transformation into diverse shapes suitable for practical applications.
Herein, a sizable C12H28NCuCl2 scintillator
screen (∼10 cm × 7 cm) was successfully prepared through
a melt-processing method, achieving X-ray imaging resolution of 9
line pairs per millimeter (9 lp/mm). This study demonstrates the potential
of melt-processable Cu(I) halides to be applied in various applications,
because of their unique properties, including facile processing, moldability,
and high X-ray luminescence.