cm9b02263_si_003.pdf (138.49 kB)
A Lead-Free Hybrid Iodide with Quantitative Response to X‑ray Radiation
journal contribution
posted on 2019-07-31, 12:08 authored by Kewen Tao, Yaobin Li, Chengmin Ji, Xitao Liu, Zhenyue Wu, Shiguo Han, Zhihua Sun, Junhua LuoSingle crystals of
lead halide hybrid perovskites (e. g., CH3NH3PbI3 and CsPbBr3) have
been developed as promising candidates for X-ray detection, owing
to their excellent attributes including low trap density, high X-ray
absorption cross section, and high carrier mobility. The toxicity
of lead, however, is a potential bottleneck that hinders their device
application toward green and sustainable competitors. Herein, we reported
a new lead-free bismuth-iodide hybrid of (H2MDAP)BiI5 (1, H2MDAP = N-methyl-1,3-diaminopropanium),
adopting one-dimensional (1D) metal-halogen frameworks, which behaves
as a potential alternative for X-ray detection. Large-size single
crystals of 1 with sizes up to 9 × 7 × 4 mm3 were successfully grown via top-seeded solution growth method.
The as-grown crystal exhibits notable semiconducting properties, including
a narrow bandgap of 1.83 eV, trap density of 3.6 × 1011 cm–3, carrier mobility of 1.42 cm2 V–1 s–1, and high X-ray absorption
coefficient. Consequently, the fabricated crystal-based X-ray photoconductor
enables the conversion of X-ray to electrical signals with a sensitivity
of ∼1.0 μC Gyair–1 cm–2. These results throw light on further exploration
on X-ray-sensitive materials based on the lead-free metal halogen
hybrids.