Abstract
Nonradiative electron-hole recombination is the bottleneck to efficient kesterite thin-film solar cells. We have performed a search for active point defect recombination centers using first-principles calculations. We show that the anion vacancy in Cu2ZnSnS4 (CZTS) is electrically benign without a donor level in the band gap. VS can still act as an efficient nonradiative site through the aid of an intermediate excited state involving electron capture by Sn. The bipolaron associated with Sn4+ to Sn2+ two-electron reduction stabilizes the neutral sulfur vacancy over the charged states; however, we demonstrate a mechanism whereby nonradiative recombination can occur via multiphonon emission. Our study highlights that defect-mediated recombination does not require a charge transition level deep in the band gap of a semiconductor. We further identify SnZn as the origin of persistent electron trapping/detrapping in kesterite photovoltaic devices, which is suppressed in the selenide compound.
| Original language | English |
|---|---|
| Pages (from-to) | 496-500 |
| Number of pages | 5 |
| Journal | ACS Energy Letters |
| Volume | 3 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2018 Feb 9 |
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All Science Journal Classification (ASJC) codes
- Chemistry (miscellaneous)
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Energy Engineering and Power Technology
- Materials Chemistry
Cite this
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Identification of Killer Defects in Kesterite Thin-Film Solar Cells. / Kim, Sunghyun; Park, Ji Sang; Walsh, Aron.
In: ACS Energy Letters, Vol. 3, No. 2, 09.02.2018, p. 496-500.Research output: Contribution to journal › Article
TY - JOUR
T1 - Identification of Killer Defects in Kesterite Thin-Film Solar Cells
AU - Kim, Sunghyun
AU - Park, Ji Sang
AU - Walsh, Aron
PY - 2018/2/9
Y1 - 2018/2/9
N2 - Nonradiative electron-hole recombination is the bottleneck to efficient kesterite thin-film solar cells. We have performed a search for active point defect recombination centers using first-principles calculations. We show that the anion vacancy in Cu2ZnSnS4 (CZTS) is electrically benign without a donor level in the band gap. VS can still act as an efficient nonradiative site through the aid of an intermediate excited state involving electron capture by Sn. The bipolaron associated with Sn4+ to Sn2+ two-electron reduction stabilizes the neutral sulfur vacancy over the charged states; however, we demonstrate a mechanism whereby nonradiative recombination can occur via multiphonon emission. Our study highlights that defect-mediated recombination does not require a charge transition level deep in the band gap of a semiconductor. We further identify SnZn as the origin of persistent electron trapping/detrapping in kesterite photovoltaic devices, which is suppressed in the selenide compound.
AB - Nonradiative electron-hole recombination is the bottleneck to efficient kesterite thin-film solar cells. We have performed a search for active point defect recombination centers using first-principles calculations. We show that the anion vacancy in Cu2ZnSnS4 (CZTS) is electrically benign without a donor level in the band gap. VS can still act as an efficient nonradiative site through the aid of an intermediate excited state involving electron capture by Sn. The bipolaron associated with Sn4+ to Sn2+ two-electron reduction stabilizes the neutral sulfur vacancy over the charged states; however, we demonstrate a mechanism whereby nonradiative recombination can occur via multiphonon emission. Our study highlights that defect-mediated recombination does not require a charge transition level deep in the band gap of a semiconductor. We further identify SnZn as the origin of persistent electron trapping/detrapping in kesterite photovoltaic devices, which is suppressed in the selenide compound.
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U2 - 10.1021/acsenergylett.7b01313
DO - 10.1021/acsenergylett.7b01313
M3 - Article
AN - SCOPUS:85041849567
VL - 3
SP - 496
EP - 500
JO - ACS Energy Letters
JF - ACS Energy Letters
SN - 2380-8195
IS - 2
ER -