Electronic, Optical, Phonon, Polaron, Carrier Transport and Scintillation Properties of Cesium Hafnium Halides Cs2HfX6,(X

极化子 材料科学 声子 有效质量(弹簧-质量系统) 带隙 凝聚态物理 电子 物理 核物理学 量子力学
作者
Mohamed E. El Sayed,Ahmed Samir,S. Naji,Mohammad N. Murshed,H. Zaari,Mohammad Al-shami
出处
期刊:Chinese Journal of Physics [Elsevier]
标识
DOI:10.1016/j.cjph.2023.09.021
摘要

In this work, we investigated the electronic, optical, phonon, polaron, and transport properties of cesium hafnium halides Cs2HfX6, X=Cl, Br and I and estimated their upper light yield. Using First-principles calculations combined the exchange-correlation energy of the Generalized Gradient Approximation GGA with the modified Becke–Johnson exchange potential (mBJ) and the spin-orbit coupling (SOC), these materials demonstrated discrete valence and conduction bands with low band dispersion and direct band gap decreasing as Cs2HfCl6 (5.48 eV)→ Cs2HfBr6 (4.18eV)→ Cs2HfI6 (2.72 eV). These obtained values are very close to the available experimental ones. Likewise, the band edge curvature of both valence band maximum (VBM) and conduction band minimum (CBM) reflects the heavier effective mass of electron at CBM Cs2HfCl6(7.58m0),Cs2HfBr6(5.94m0),Cs2HfI6(3.92m0) compared to that of the hole at VBM Cs2HfCl6(6.12m0),Cs2HfBr6(3.72m0),Cs2HfI6(2.34m0). Moreover, these materials exhibited a high transmittance rate, in their emission range, about: 93.57 % for Cs2HfCl6 91.25% for Cs2HfBr6 and 88.1% for Cs2HfI6, which is adequate to minimize the scintillated photons loss. The phonon dispersion and the normal modes for Γ point were calculated and discussed. Only three longitudinal optical phonon modes were identified active and their contribution to the ionic dielectric constant was calculated. Having First-principles results, polaron properties, the temperature dependence of polaron mobility, and relaxation time were calculated. These materials showed moderate electron (hole)-phonon couplings αe=6.72(αh=6.04) for Cs2HfCl6,αe=8.26(αh=6.54) for Cs2HfBr6 and αe=6.16(αh=4.76) for Cs2HfI6 compared to other polar materials leading to large polaron mass, high scattering rate, small relaxation time, and low electron (hole) room-temperature mobility 0.14cm2V−1s−1 (0.23 cm2V−1s−1) for Cs2HfCl6 0.14cm2V−1s−1 (0.45 cm2V−1s−1) for Cs2HfBr6 and 0.62cm2V−1s−1 (1.81 cm2V−1s−1) for Cs2HfI6which has only a positive role via the increase of the recombination yield. While such low mobility definitely limited their use in solar cell applications. Moreover, the upper light yield of these materials was estimated for the polaron and simple phenomenological models by taking the needed material inputs to these models from First-principles calculations. The results of latter one were 58,290 photon/MeV for Cs2HfCl6 76,685photon/MeV for Cs2HfBr6 and 118,000photon/MeV for Cs2HfI6 compared to the maximum experimental values 54,000 photon/MeV for Cs2HfCl6 61,500photon/MeV for Cs2HfBr6 and 70,000photon/MeV for Cs2HfI6. These computational findings may add strong evidence for suggesting experimental improvement of the crystal growth conditions and explain the remarkable scintillation properties of these materials as new and efficient gamma- and X-rays scintillators.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
大幅提高文件上传限制,最高150M (2024-4-1)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
ccccc1998发布了新的文献求助10
刚刚
刚刚
1秒前
2秒前
iuv发布了新的文献求助10
2秒前
aaaa完成签到,获得积分10
3秒前
zhangqin完成签到,获得积分10
4秒前
苏满天发布了新的文献求助30
6秒前
6秒前
zhangqin发布了新的文献求助10
7秒前
8秒前
Singularity应助圆圆采纳,获得10
8秒前
鹿不可完成签到,获得积分10
8秒前
椿翊给椿翊的求助进行了留言
9秒前
ding应助天真芷云采纳,获得10
10秒前
11秒前
Grace发布了新的文献求助10
12秒前
Admin发布了新的文献求助10
13秒前
16秒前
18秒前
欢呼冬瓜完成签到 ,获得积分10
18秒前
不安青牛应助Admin采纳,获得10
20秒前
20秒前
haikuotian发布了新的文献求助10
21秒前
善学以致用应助xsq86采纳,获得10
22秒前
22秒前
24秒前
24秒前
天真芷云发布了新的文献求助10
27秒前
jie发布了新的文献求助10
27秒前
8R60d8应助科研通管家采纳,获得10
27秒前
orixero应助科研通管家采纳,获得10
27秒前
嗯哼应助科研通管家采纳,获得20
27秒前
8R60d8应助科研通管家采纳,获得10
27秒前
8R60d8应助科研通管家采纳,获得10
27秒前
嗯哼应助科研通管家采纳,获得20
27秒前
8R60d8应助科研通管家采纳,获得10
27秒前
嗯哼应助科研通管家采纳,获得20
27秒前
完美世界应助科研通管家采纳,获得10
27秒前
汉堡包应助科研通管家采纳,获得10
27秒前
高分求助中
Evolution 10000
ISSN 2159-8274 EISSN 2159-8290 1000
Becoming: An Introduction to Jung's Concept of Individuation 600
Ore genesis in the Zambian Copperbelt with particular reference to the northern sector of the Chambishi basin 500
A new species of Coccus (Homoptera: Coccoidea) from Malawi 500
A new species of Velataspis (Hemiptera Coccoidea Diaspididae) from tea in Assam 500
PraxisRatgeber: Mantiden: Faszinierende Lauerjäger 500
热门求助领域 (近24小时)
化学 医学 生物 材料科学 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 基因 遗传学 催化作用 物理化学 免疫学 量子力学 细胞生物学
热门帖子
关注 科研通微信公众号,转发送积分 3161703
求助须知:如何正确求助?哪些是违规求助? 2812994
关于积分的说明 7898049
捐赠科研通 2471906
什么是DOI,文献DOI怎么找? 1316269
科研通“疑难数据库(出版商)”最低求助积分说明 631278
版权声明 602129