All-inorganic copper-halide perovskites for large-Stokes shift and ten-nanosecond-emission scintillators

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2024-02, Vol.12 (7), p.2398-249
• Main Authors: Haposan, Tobias, Arramel, Arramel, Maulida, Pramitha Yuniar Diah, Hartati, Sri, Afkauni, Afif Akmal, Mahyuddin, Muhammad Haris, Zhang, Lei, Kowal, Dominik, Witkowski, Marcin Eugeniusz, Drozdowski, Konrad Jacek, Makowski, Michal, Drozdowski, Winicjusz, Diguna, Lina Jaya, Birowosuto, Muhammad Danang
• Format: Article
• Language: English
• Subjects: Afterglows; Copper; Decay rate; Emission; Lead free; Optoelectronics; Perovskites; Room temperature; Scintillation; Scintillation counters
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d3tc03977c

The recent surge of interest in low-dimensional lead-free copper halide perovskites (CHPs) has driven significant progress in optoelectronics and scintillating materials. However, the development of green-based synthetic routes for CHPs, aimed at creating fast-decaying scintillators with ultrasensitive X-ray detection, remains elusive. In this study, we utilize a mechanochemical method to obtain 1D CHP (CsCu 2 I 3 ) and 0D CHPs (Cs 3 Cu 2 X 5 (X = I, Br)) focusing on the mixing of I and Br anions with different molar ratios (I : Br = 4 : 1 and 3 : 2). CsCu 2 I 3 and Cs 3 Cu 2 I 5 exhibit a substantial large Stokes shift (SS) of 1.75 ± 0.02 eV and 1.57 ± 0.05 eV with the former displaying the absence of afterglow, whereas the latter has a deep trap of ∼500 meV, complicating the scintillation mechanism and resulting in a slower decay component. The CsCu 2 I 3 scintillation decay time is primarily characterized by a fast component ( τ 1 ) of 9.30 ± 0.01 ns, accounting for contribution ( C 1 ) of 43% from the total emission. This fast decay component of ∼10 ns has not been previously reported in the family of CHPs. Similarly, τ 1 of 10.9 ± 0.6 ns is obtained in Cs 3 Cu 2 I 5 , but when compared to its counterpart, C 1 is only 3%. Upon increasing the Br substitution in Cs 3 Cu 2 I 5 , we observe that the traps become shallower, with energies ranging from 208 ± 21 to 121 ± 18 meV, along with an appreciable trap concentration of ∼10 4 . The C 1 of τ 1 also increases with higher Br concentration, reaching a maximum value of 29%. Unfortunately, this increased contribution in decay times is accompanied by a decrease in light yields (Cs 3 Cu 2 I 5 has 16.5 ph per keV at room temperature (RT)) as thermal quenching processes predominate throughout the entire series of CHPs at RT. Our work provides valuable insights into the tunable structure-property relationship through the I : Br composition ratio of CHPs, hence advancing scintillation performance by rational design towards timing applications. Demonstration of how rational design affects self-trapped emission characteristics and scintillation properties in mechanochemically synthesised caesium copper halide perovskites.