In:
Advanced Materials, Wiley, Vol. 30, No. 46 ( 2018-11)
Abstract:
The sensitive detection of X‐rays embodies an important research area, being motivated by a common desire to minimize the radiation doses required for detection. Among metal halide perovskites, the double‐perovskite Cs 2 AgBiBr 6 system has emerged as a promising candidate for the detection of X‐rays, capable of high X‐ray stability and sensitivity (105 μC Gy −1 cm −2 ). Herein, the important photophysical pathways in single‐crystal Cs 2 AgBiBr 6 are detailed at both room (RT) and liquid‐nitrogen (LN 2 T) temperatures, with emphasis made toward understanding the carrier dynamics that influence X‐ray sensitivity. This study draws upon several optical probes and an RT excitation model is developed which is far from optimal, being plagued by a large trap density and fast free‐carrier recombination pathways. Substantially improved operating conditions are revealed at 77 K, with a long fundamental carrier lifetime ( 〉 1.5 µs) and a marked depopulation of parasitic recombination pathways. The temperature dependence of a single‐crystal Cs 2 AgBiBr 6 X‐ray detecting device is characterized and a strong and monotonic enhancement to the X‐ray sensitivity upon cooling is demonstrated, moving from 316 μC Gy −1 cm −2 at RT to 988 μC Gy −1 cm −2 near LN 2 T. It is concluded that even modest cooling—via a Peltier device—will facilitate a substantial enhancement in device performance, ultimately lowering the radiation doses required.
Type of Medium:
Online Resource
ISSN:
0935-9648
,
1521-4095
DOI:
10.1002/adma.201804450
Language:
English
Publisher:
Wiley
Publication Date:
2018
detail.hit.zdb_id:
1474949-X
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