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Title: Distinguishing bulk and surface recombination in CdTe thin films and solar cells using time-resolved terahertz and photoluminescence spectroscopies

Abstract

Understanding the nature of recombination and its dependence on defects and interfaces is essential for engineering materials and contacts for higher open circuit voltage (Voc) and power conversion efficiency in photovoltaic (PV) devices. Time-resolved photoluminescence (TRPL) has conventionally been used to evaluate recombination, but carrier redistribution often dominates the response at short times. In this work, we report on the quantification of carrier dynamics and recombination mechanisms by complementary use of both time-resolved terahertz spectroscopy (TRTS) and TRPL combined with numerical modeling of the continuity equations and Poisson’s equation. We have demonstrated this approach using CdTe thin films. A thin film stack with CdTe fabricated by vapor transport deposition and treated with CdCl2 exhibited a bulk lifetime of 1.7 ± 0.1 ns, negligible CdTe/CdS interface recombination velocity, and back surface recombination velocity of 6.3 ± 1.3 x104 cm/s. In contrast, a film stack without CdCl2 treatment had a bulk lifetime of only 68 ± 12 ps and a higher interface recombination velocity of 4 ± 2 x108 cm/s. By determining the locus and mechanisms of performance-limiting recombination, we can accelerate the development of thin-film PVs with higher Voc and efficiency. While the method has been demonstrated here using CdTe, itmore » is also applicable to perovskites, Cu(InGa)Se2, Cu2ZnSn(S,Se)4, and emerging technologies.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [1]
  1. Drexel Univ., Philadelphia, PA (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. Univ. of Delaware, Newark, DE (United States)
Publication Date:
Research Org.:
Drexel Univ., Philadelphia, PA (United States); National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
OSTI Identifier:
1828279
Alternate Identifier(s):
OSTI ID: 1828070; OSTI ID: 1834559
Report Number(s):
NREL/JA-5900-81617
Journal ID: ISSN 0021-8979; DE-EE0008986; TRN: US2216039
Grant/Contract Number:  
EE0008986; AC36-08GO28308
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 130; Journal Issue: 16; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; photovoltaics; solar cells; CdTe; recombination; time-resolved terahertz spectroscopy; time-resolved photoluminescence; semiconductors; terahertz spectroscopy; thin film devices

Citation Formats

Taheri, Mohammad M., Truong, Triet M., Li, Siming, Shafarman, William N., McCandless, Brian E., and Baxter, Jason B. Distinguishing bulk and surface recombination in CdTe thin films and solar cells using time-resolved terahertz and photoluminescence spectroscopies. United States: N. p., 2021. Web. doi:10.1063/5.0064730.
Taheri, Mohammad M., Truong, Triet M., Li, Siming, Shafarman, William N., McCandless, Brian E., & Baxter, Jason B. Distinguishing bulk and surface recombination in CdTe thin films and solar cells using time-resolved terahertz and photoluminescence spectroscopies. United States. https://doi.org/10.1063/5.0064730
Taheri, Mohammad M., Truong, Triet M., Li, Siming, Shafarman, William N., McCandless, Brian E., and Baxter, Jason B. Thu . "Distinguishing bulk and surface recombination in CdTe thin films and solar cells using time-resolved terahertz and photoluminescence spectroscopies". United States. https://doi.org/10.1063/5.0064730. https://www.osti.gov/servlets/purl/1828279.
@article{osti_1828279,
title = {Distinguishing bulk and surface recombination in CdTe thin films and solar cells using time-resolved terahertz and photoluminescence spectroscopies},
author = {Taheri, Mohammad M. and Truong, Triet M. and Li, Siming and Shafarman, William N. and McCandless, Brian E. and Baxter, Jason B.},
abstractNote = {Understanding the nature of recombination and its dependence on defects and interfaces is essential for engineering materials and contacts for higher open circuit voltage (Voc) and power conversion efficiency in photovoltaic (PV) devices. Time-resolved photoluminescence (TRPL) has conventionally been used to evaluate recombination, but carrier redistribution often dominates the response at short times. In this work, we report on the quantification of carrier dynamics and recombination mechanisms by complementary use of both time-resolved terahertz spectroscopy (TRTS) and TRPL combined with numerical modeling of the continuity equations and Poisson’s equation. We have demonstrated this approach using CdTe thin films. A thin film stack with CdTe fabricated by vapor transport deposition and treated with CdCl2 exhibited a bulk lifetime of 1.7 ± 0.1 ns, negligible CdTe/CdS interface recombination velocity, and back surface recombination velocity of 6.3 ± 1.3 x104 cm/s. In contrast, a film stack without CdCl2 treatment had a bulk lifetime of only 68 ± 12 ps and a higher interface recombination velocity of 4 ± 2 x108 cm/s. By determining the locus and mechanisms of performance-limiting recombination, we can accelerate the development of thin-film PVs with higher Voc and efficiency. While the method has been demonstrated here using CdTe, it is also applicable to perovskites, Cu(InGa)Se2, Cu2ZnSn(S,Se)4, and emerging technologies.},
doi = {10.1063/5.0064730},
journal = {Journal of Applied Physics},
number = 16,
volume = 130,
place = {United States},
year = {Thu Oct 28 00:00:00 EDT 2021},
month = {Thu Oct 28 00:00:00 EDT 2021}
}

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