α-Particle Detection and Charge Transport Characteristics in the A3M2I9 Defect Perovskites (A = Cs, Rb; M = Bi, Sb)
α-Particle Detection and Charge Transport Characteristics in the A3M2I9 Defect Perovskites (A = Cs, Rb; M = Bi, Sb)
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DOI：
10.1021/acsphotonics.8b00813
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发表时间：
2018-09-01
期刊：
影响因子：
7
通讯作者：
Wessels, Bruce W.
中科院分区：
文献类型：
--
作者：
McCall, Kyle M.;Liu, Zhifu;Wessels, Bruce W.
我们研究了缺陷钙钛矿A（3）M（2）I（9）（A = Cs，Rb; M = Bi，Sb）作为辐射探测材料。布里奇曼生长的A（3）M（2）I（9）单晶的相纯度通过高分辨率同步加速器X射线衍射得到证实，而密度泛函理论计算（DFT）显示出这些层状材料在面外方向上令人惊讶的色散带，空穴和电子的有效质量都很低。因此，四种A（3）M（2）I（9）缺陷钙钛矿中的每一种都显示出对用于空穴和电子电极配置的Am-241 α粒子照射的响应，这是类似于3D卤化物钙钛矿的显著双极响应。电子响应光谱用于估计这些材料中电子的迁移率-寿命积（mu tau）（e），Rb 3Bi 2 I9显示最低（mu tau）（e）值为1.7 x 10（-6）cm（2）V-1，Cs3 Bi 2 I9显示最高（mu tau）（e）值为5.4 x 10（-5）cm（2）V-1。α粒子产生的脉冲的上升时间用于估计A（3）M（2）I（9）缺陷钙钛矿的电子迁移率，其范围从Rb 3Sb 2 I9的0.32 cm（2）V（-1）s（-1）到Cs3 Bi 2 I9的4.3 cm（2）V（-1）s（-1）。对空穴响应光谱的类似分析得出了每种A（3）M（2）I（9）化合物的（mu tau）（h）值，Cs3 Bi 2 I9再次显示出最高的（mu tau）（h）值，为1.8 × 10（-5）cm（2）V-1，而Rb 3Bi 2 I9显示出最低的（mu tau）（h）值，为2.0 × 10（-6）cm（2）V-1。上升时间分析给出的空穴迁移率范围从Cs3 Bi 2 I9的1.7 cm（2），AT（-1）s（-1）到Cs3 Sb 2 I9的0.14 cm（2）V-1 s（-1）。将实验电子和空穴迁移率与从DFT计算获得的有效质量进行比较，发现了相当大的差异，这可能表明由于电子-声子相互作用导致的电荷载流子的自陷。A（3）M（2）I（9）缺陷钙钛矿的α粒子响应证明了它们作为半导体辐射探测器的潜力，其中Cs3 Bi 2 I9和Cs3 Sb 2 I9显示出最有希望的。
We have investigated the defect perovskites A(3)M(2)I(9) (A = Cs, Rb; M = Bi, Sb) as materials for radiation detection. The phase purity of Bridgman-grown A(3)M(2)I(9) single crystals was confirmed via high-resolution synchrotron X-ray diffraction, while density functional theory calculations (DFT) show surprisingly dispersive bands in the out-of-plane direction for these layered materials, with low effective masses for both holes and electrons. Accordingly, each of the four A(3)M(2)I(9) defect perovskites showed response to Am-241 alpha-particle irradiation for hole and electron electrode configurations, a remarkable ambipolar response that resembles the 3D halide perovskites. The electron response spectra were used to estimate the mobility-lifetime product (mu tau)(e) for electrons in these materials, with Rb3Bi2I9 showing the lowest (mu tau)(e) value of 1.7 x 10(-6) cm(2) V-1 and Cs3Bi2I9 the highest (mu tau)(e) of 5.4 x 10(-5) cm(2) V-1. The rise time of the alpha-particle-generated pulse was used to estimate the electron mobility, of the A(3)M(2)I(9) defect perovskites, which ranged from 0.32 cm(2) V(-1)s(-1) for Rb3Sb2I9 to 4.3 cm(2) V(-1)s(-1) in Cs3Bi2I9. Similar analysis of the hole response spectra yielded (mu tau)(h) values for each A(3)M(2)I(9) compound, with Cs3Bi2I9 again showing the highest (mu tau)(h) value of 1.8 x 10(-5) cm(2) V-1, while Rb3Bi2I9 showed the lowest (mu tau)(h) with 2.0 x 10(-6) cm(2) V-1. Rise time analysis gave hole mobilities ranging from 1.7 cm(2), AT(-1) s(-1) for Cs3Bi2I9 to 0.14 cm(2) V-1 s(-1) for Cs3Sb2I9. Comparing the experimental electron and hole mobilities to the effective masses obtained from DFT calculations revealed sizable discrepancies, possibly indicating self-trapping of charge carriers due to electron-phonon interactions. The alpha-particle response of the A(3)M(2)I(9) defect perovskites demonstrates their potential as semiconductor radiation detectors, with Cs3Bi2I9 and Cs3Sb2I9 showing the most promise.