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Title: Large dielectric constant, high acceptor density, and deep electron traps in perovskite solar cell material CsGeI 3

Abstract

Here we report that many metal halides that contain cations with the ns 2 electronic configuration have recently been discovered as high-performance optoelectronic materials. In particular, solar cells based on lead halide perovskites have shown great promise as evidenced by the rapid increase of the power conversion efficiency. In this paper, we show density functional theory calculations of electronic structure and dielectric and defect properties of CsGeI 3 (a lead-free halide perovskite material). The potential of CsGeI 3 as a solar cell material is assessed based on its intrinsic properties. We find anomalously large Born effective charges and a large static dielectric constant dominated by lattice polarization, which should reduce carrier scattering, trapping, and recombination by screening charged defects and impurities. Defect calculations show that CsGeI 3 is a p-type semiconductor and its hole density can be modified by varying the chemical potentials of the constituent elements. Despite the reduction of long-range Coulomb attraction by strong screening, the iodine vacancy in CsGeI3 is found to be a deep electron trap due to the short-range potential, i.e., strong Ge–Ge covalent bonding, which should limit electron transport efficiency in p-type CsGeI 3. This is in contrast to the shallow iodine vacancies foundmore » in several Pb and Sn halide perovskites (e.g., CH 3NH 3PbI 3, CH 3NH 3SnI 3, and CsSnI 3). The low-hole-density CsGeI 3 may be a useful solar absorber material but the presence of the low-energy deep iodine vacancy may significantly reduce the open circuit voltage of the solar cell. Still, on the other hand, CsGeI 3 may be used as an efficient hole transport material in solar cells due to its small hole effective mass, the absence of low-energy deep hole traps, and the favorable band offset with solar absorber materials such as dye molecules and CH 3NH 3PbI 3.« less

Authors:
 [1];  [2];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division and Center for Radiation Detection Materials and Systems
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division and Center for Radiation Detection Materials and Systems; Beihang Univ., Beijing (China). School of Physics and Nuclear Energy Engineering
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1328304
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 4; Journal Issue: 36; Journal ID: ISSN 2050-7488
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Ming, Wenmei, Shi, Hongliang, and Du, Mao-Hua. Large dielectric constant, high acceptor density, and deep electron traps in perovskite solar cell material CsGeI3. United States: N. p., 2016. Web. doi:10.1039/C6TA04685A.
Ming, Wenmei, Shi, Hongliang, & Du, Mao-Hua. Large dielectric constant, high acceptor density, and deep electron traps in perovskite solar cell material CsGeI3. United States. doi:10.1039/C6TA04685A.
Ming, Wenmei, Shi, Hongliang, and Du, Mao-Hua. Fri . "Large dielectric constant, high acceptor density, and deep electron traps in perovskite solar cell material CsGeI3". United States. doi:10.1039/C6TA04685A. https://www.osti.gov/servlets/purl/1328304.
@article{osti_1328304,
title = {Large dielectric constant, high acceptor density, and deep electron traps in perovskite solar cell material CsGeI3},
author = {Ming, Wenmei and Shi, Hongliang and Du, Mao-Hua},
abstractNote = {Here we report that many metal halides that contain cations with the ns2 electronic configuration have recently been discovered as high-performance optoelectronic materials. In particular, solar cells based on lead halide perovskites have shown great promise as evidenced by the rapid increase of the power conversion efficiency. In this paper, we show density functional theory calculations of electronic structure and dielectric and defect properties of CsGeI3 (a lead-free halide perovskite material). The potential of CsGeI3 as a solar cell material is assessed based on its intrinsic properties. We find anomalously large Born effective charges and a large static dielectric constant dominated by lattice polarization, which should reduce carrier scattering, trapping, and recombination by screening charged defects and impurities. Defect calculations show that CsGeI3 is a p-type semiconductor and its hole density can be modified by varying the chemical potentials of the constituent elements. Despite the reduction of long-range Coulomb attraction by strong screening, the iodine vacancy in CsGeI3 is found to be a deep electron trap due to the short-range potential, i.e., strong Ge–Ge covalent bonding, which should limit electron transport efficiency in p-type CsGeI3. This is in contrast to the shallow iodine vacancies found in several Pb and Sn halide perovskites (e.g., CH3NH3PbI3, CH3NH3SnI3, and CsSnI3). The low-hole-density CsGeI3 may be a useful solar absorber material but the presence of the low-energy deep iodine vacancy may significantly reduce the open circuit voltage of the solar cell. Still, on the other hand, CsGeI3 may be used as an efficient hole transport material in solar cells due to its small hole effective mass, the absence of low-energy deep hole traps, and the favorable band offset with solar absorber materials such as dye molecules and CH3NH3PbI3.},
doi = {10.1039/C6TA04685A},
journal = {Journal of Materials Chemistry. A},
issn = {2050-7488},
number = 36,
volume = 4,
place = {United States},
year = {2016},
month = {1}
}

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Cited by: 11 works
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Works referenced in this record:

Enhanced Born charges in III-VII, IV-VII 2 , and V-VII 3 compounds
journal, July 2010


Efficient carrier transport in halide perovskites: theoretical perspectives
journal, January 2014


Electron-hole diffusion lengths > 175 μm in solution-grown CH 3 NH 3 PbI 3 single crystals
journal, January 2015


Electron-Hole Diffusion Lengths Exceeding 1 Micrometer in an Organometal Trihalide Perovskite Absorber
journal, October 2013

  • Stranks, S. D.; Eperon, G. E.; Grancini, G.
  • Science, Vol. 342, Issue 6156, p. 341-344
  • DOI: 10.1126/science.1243982

Long-Range Balanced Electron- and Hole-Transport Lengths in Organic-Inorganic CH3NH3PbI3
journal, October 2013


High Charge Carrier Mobilities and Lifetimes in Organolead Trihalide Perovskites
journal, December 2013

  • Wehrenfennig, Christian; Eperon, Giles E.; Johnston, Michael B.
  • Advanced Materials, Vol. 26, Issue 10
  • DOI: 10.1002/adma.201305172

Thallium Bromide Nuclear Radiation Detector Development
journal, August 2009

  • Churilov, Alexei V.; Ciampi, Guido; Kim, Hadong
  • IEEE Transactions on Nuclear Science, Vol. 56, Issue 4
  • DOI: 10.1109/TNS.2009.2021424

TlBr and TlBrxI1−x crystals for γ-ray detectors
journal, April 2010


Thallium Chalcohalides for X-ray and γ-ray Detection
journal, July 2011

  • Johnsen, Simon; Liu, Zhifu; Peters, John A.
  • Journal of the American Chemical Society, Vol. 133, Issue 26
  • DOI: 10.1021/ja202540t

Photoconductivity in Tl 6 SI 4 : A Novel Semiconductor for Hard Radiation Detection
journal, July 2013

  • Nguyen, Sandy L.; Malliakas, Christos D.; Peters, John A.
  • Chemistry of Materials, Vol. 25, Issue 14
  • DOI: 10.1021/cm401406j

Crystal Growth of the Perovskite Semiconductor CsPbBr 3 : A New Material for High-Energy Radiation Detection
journal, June 2013

  • Stoumpos, Constantinos C.; Malliakas, Christos D.; Peters, John A.
  • Crystal Growth & Design, Vol. 13, Issue 7
  • DOI: 10.1021/cg400645t

High-Gain and Low-Driving-Voltage Photodetectors Based on Organolead Triiodide Perovskites
journal, January 2015


Ultrahigh Gain, Low Noise, Ultraviolet Photodetectors with Highly Aligned Organic Crystals
journal, November 2015


Sensitive X-ray detectors made of methylammonium lead tribromide perovskite single crystals
journal, March 2016


Goldschmidt’s Rules and Strontium Replacement in Lead Halogen Perovskite Solar Cells: Theory and Preliminary Experiments on CH 3 NH 3 SrI 3
journal, November 2015

  • Jacobsson, T. Jesper; Pazoki, Meysam; Hagfeldt, Anders
  • The Journal of Physical Chemistry C, Vol. 119, Issue 46
  • DOI: 10.1021/acs.jpcc.5b06436

Effect of metal cation replacement on the electronic structure of metalorganic halide perovskites: Replacement of lead with alkaline-earth metals
journal, April 2016


Investigation of Bismuth Triiodide (BiI 3 ) for Photovoltaic Applications
journal, October 2015

  • Brandt, Riley E.; Kurchin, Rachel C.; Hoye, Robert L. Z.
  • The Journal of Physical Chemistry Letters, Vol. 6, Issue 21
  • DOI: 10.1021/acs.jpclett.5b02022

Bismuth chalcohalides and oxyhalides as optoelectronic materials
journal, March 2016


Thin-Film Preparation and Characterization of Cs 3 Sb 2 I 9 : A Lead-Free Layered Perovskite Semiconductor
journal, August 2015


CsSnI3 : Semiconductor or Metal? High Electrical Conductivity and Strong Near-Infrared Photoluminescence from a Single Material. High Hole Mobility and Phase-Transitions
journal, May 2012

  • Chung, In; Song, Jung-Hwan; Im, Jino
  • Journal of the American Chemical Society, Vol. 134, Issue 20, p. 8579-8587
  • DOI: 10.1021/ja301539s

All-solid-state dye-sensitized solar cells with high efficiency
journal, May 2012

  • Chung, In; Lee, Byunghong; He, Jiaqing
  • Nature, Vol. 485, Issue 7399, p. 486-489
  • DOI: 10.1038/nature11067

Lead-free solid-state organic–inorganic halide perovskite solar cells
journal, May 2014

  • Hao, Feng; Stoumpos, Constantinos C.; Cao, Duyen Hanh
  • Nature Photonics, Vol. 8, Issue 6
  • DOI: 10.1038/nphoton.2014.82

Lead-free organic–inorganic tin halide perovskites for photovoltaic applications
journal, January 2014

  • Noel, Nakita K.; Stranks, Samuel D.; Abate, Antonio
  • Energy Environ. Sci., Vol. 7, Issue 9
  • DOI: 10.1039/C4EE01076K

Lead-free germanium iodide perovskite materials for photovoltaic applications
journal, January 2015

  • Krishnamoorthy, Thirumal; Ding, Hong; Yan, Chen
  • Journal of Materials Chemistry A, Vol. 3, Issue 47
  • DOI: 10.1039/C5TA05741H

Overcoming Short-Circuit in Lead-Free CH 3 NH 3 SnI 3 Perovskite Solar Cells via Kinetically Controlled Gas–Solid Reaction Film Fabrication Process
journal, February 2016

  • Yokoyama, Takamichi; Cao, Duyen H.; Stoumpos, Constantinos C.
  • The Journal of Physical Chemistry Letters, Vol. 7, Issue 5
  • DOI: 10.1021/acs.jpclett.6b00118

Influence of Defects and Synthesis Conditions on the Photovoltaic Performance of Perovskite Semiconductor CsSnI 3
journal, October 2014

  • Xu, Peng; Chen, Shiyou; Xiang, Hong-Jun
  • Chemistry of Materials, Vol. 26, Issue 20
  • DOI: 10.1021/cm503122j

Semiconducting Tin and Lead Iodide Perovskites with Organic Cations: Phase Transitions, High Mobilities, and Near-Infrared Photoluminescent Properties
journal, July 2013

  • Stoumpos, Constantinos C.; Malliakas, Christos D.; Kanatzidis, Mercouri G.
  • Inorganic Chemistry, Vol. 52, Issue 15, p. 9019-9038
  • DOI: 10.1021/ic401215x

Hybrid Germanium Iodide Perovskite Semiconductors: Active Lone Pairs, Structural Distortions, Direct and Indirect Energy Gaps, and Strong Nonlinear Optical Properties
journal, May 2015

  • Stoumpos, Constantinos C.; Frazer, Laszlo; Clark, Daniel J.
  • Journal of the American Chemical Society, Vol. 137, Issue 21
  • DOI: 10.1021/jacs.5b01025

The emergence of perovskite solar cells
journal, July 2014

  • Green, Martin A.; Ho-Baillie, Anita; Snaith, Henry J.
  • Nature Photonics, Vol. 8, Issue 7, p. 506-514
  • DOI: 10.1038/nphoton.2014.134

Unusual defect physics in CH 3 NH 3 PbI 3 perovskite solar cell absorber
journal, February 2014

  • Yin, Wan-Jian; Shi, Tingting; Yan, Yanfa
  • Applied Physics Letters, Vol. 104, Issue 6
  • DOI: 10.1063/1.4864778

Shallow halogen vacancies in halide optoelectronic materials
journal, November 2014


Generalized Gradient Approximation Made Simple
journal, October 1996

  • Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
  • Physical Review Letters, Vol. 77, Issue 18, p. 3865-3868
  • DOI: 10.1103/PhysRevLett.77.3865

Band Offsets at Semiconductor-Oxide Interfaces from Hybrid Density-Functional Calculations
journal, September 2008


Alignment of defect levels and band edges through hybrid functionals: Effect of screening in the exchange term
journal, May 2010


Assessing the accuracy of hybrid functionals in the determination of defect levels: Application to the As antisite in GaAs
journal, August 2011


Assessment of correction methods for the band-gap problem and for finite-size effects in supercell defect calculations: Case studies for ZnO and GaAs
journal, December 2008


Kristallstrukturen und Phasentransformationen von Caesiumtrihalogenogermanaten(II) CsGeX3 (X = Cl, Br, I)
journal, February 1987

  • Thiele, Gerhard; Rotter, Heinz Wilhelm; Schmidt, Klaus Dieter
  • Zeitschrift f�r anorganische und allgemeine Chemie, Vol. 545, Issue 2
  • DOI: 10.1002/zaac.19875450217

Projector augmented-wave method
journal, December 1994


Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996


From ultrasoft pseudopotentials to the projector augmented-wave method
journal, January 1999


Electronic structure and defect properties of Tl 6 SeI 4 : Density functional calculations
journal, October 2012


Native defects in Tl 6 SI 4 : Density functional calculations
journal, May 2015

  • Shi, Hongliang; Du, Mao-Hua
  • Journal of Applied Physics, Vol. 117, Issue 17
  • DOI: 10.1063/1.4917532

Fast Diffusion of Native Defects and Impurities in Perovskite Solar Cell Material CH 3 NH 3 PbI 3
journal, June 2016


Dielectric study of CH3NH3PbX3 (X = Cl, Br, I)
journal, July 1992

  • Onoda-Yamamuro, Noriko; Matsuo, Takasuke; Suga, Hiroshi
  • Journal of Physics and Chemistry of Solids, Vol. 53, Issue 7
  • DOI: 10.1016/0022-3697(92)90121-S

Electro-optics of perovskite solar cells
journal, December 2014

  • Lin, Qianqian; Armin, Ardalan; Nagiri, Ravi Chandra Raju
  • Nature Photonics, Vol. 9, Issue 2
  • DOI: 10.1038/nphoton.2014.284

Analysis of Multivalley and Multibandgap Absorption and Enhancement of Free Carriers Related to Exciton Screening in Hybrid Perovskites
journal, May 2014

  • Even, Jacky; Pedesseau, Laurent; Katan, Claudine
  • The Journal of Physical Chemistry C, Vol. 118, Issue 22
  • DOI: 10.1021/jp503337a

First-principles study of native defects in TlBr: Carrier trapping, compensation, and polarization phemomenon
journal, September 2010


    Works referencing / citing this record:

    Lead‐Free Tin‐Based Perovskite Solar Cells: Strategies Toward High Performance
    journal, May 2019