Bi-Based Perovskite Materials for High-Sensitivity Gamma Ray Detection

Introduction

Bismuth-based perovskite materials have emerged as promising candidates for gamma ray detection due to their high atomic number, tunable optoelectronic properties, high bandgap, and cost-effective synthesis. This study investigates the structural, optical, and radiation detection properties of a (CH₃NH₃)₃Bi₂Cl₉ (MABiCl) perovskite material in pelletized form.

Methods

Synthesis of the lead-free Bi-based perovskite MABiCl material as a light absorber was performed by mixing a 3:2 M ratio of CH₃NH₃Cl and BiCl₃ at 50^◦C in DMF. The solution was stirred for half an hour, resulting in a white foggy solution. In total, 20 ml ethyl alcohol was added to achieve a white precipitate. The solution was filtered and dried under a constant temperature of 60^◦C under vacuum conditions to obtain MABiCl powder.

Results

X-ray diffraction (XRD) analysis confirms the formation of a highly crystalline perovskite structure with well-defined peaks, indicating phase purity. UV-Vis spectroscopy reveals a bandgap of 2.4 eV, which is suitable for efficient charge carrier generation under gamma ray exposure. Temperature-dependent electrical study, conducted at both high and low temperatures, demonstrate the material’s thermal stability and consistent performance across a wide temperature range, making it viable for diverse operational environments. Current versus time measurements under gamma ray irradiation from various sources (Co⁶⁰, Cs¹³⁷, Na²⁴) exhibit a rapid and reproducible photo response, with high sensitivity and low noise, indicating effective charge collection and detection efficiency. The material’s response to gamma rays shows a linear correlation between current output and radiation dose, highlighting its potential for quantitative detection applications.

Conclusion

These findings suggest that the Bi-based perovskite material possesses favourable properties for gamma ray detection, including structural robustness, suitable optical characteristics, and reliable radiation response. Further optimization of material composition and device fabrication could enhance detection efficiency and scalability, paving the way for practical applications in medical imaging, nuclear security, and radiation monitoring.