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Elucidating the role of TiCl4post-treatment on percolation of TiO2electron transport layer in perovskite solar cells

Elucidating the role of TiCl4post-treatment on percolation of TiO2electron transport layer in perovskite solar cells
Elucidating the role of TiCl4post-treatment on percolation of TiO2electron transport layer in perovskite solar cells

The ideal electron transport layer of a high performance perovskite solar cell should have good optical transparency, high electron mobility, and an energy level alignment well-matched with the perovskite material. In this work, we investigate the role of TiCl4 post-treatment of the mesoporous TiO2 electron transport layer by varying the concentration of TiCl4 and characterizing optical and electrical properties, charge carrier dynamics, and photovoltaic performance of mesoscopic CH3NH3PbI3 solar cells. It is found that the TiCl4 treatment provides an additional interconnection between the TiO2 particles, leading to better percolation as evident from high resolution cross-section images and chemical maps. This enhances effective electron mobility in the material as well as significantly reduces average sub-bandgap absorption due to defects and electronic disorder determined by photothermal deflection spectroscopy. Moreover, improvement of interfacial contact due to a smoother surface contributes to more efficient charge extraction and suppressed charge recombination and reduced hysteresis. As a result, the optimized device based on TiCl4 post-treated mesoporous TiO2 achieved the highest conversion efficiency of 17.4% compared with 14.1% for the device with pristine mesoporous TiO2.

TiCl4 post-treated mesoporous TiO2 electron transport layer, photovoltaic performance, perovskite solar cells
0022-3727
Amalathas, Amalraj Peter
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Landová, Lucie
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Huminiuc, Teodor
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Horák, Lukáš
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Conrad, Brianna
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Polcar, Tomas
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Holovský, Jakub
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Amalathas, Amalraj Peter
daa84adb-540a-4144-b1df-c570a6bf8a56
Landová, Lucie
5a8c555c-7c68-4cfa-8561-b3884d52c97e
Huminiuc, Teodor
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Horák, Lukáš
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Conrad, Brianna
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Polcar, Tomas
c669b663-3ba9-4e7b-9f97-8ef5655ac6d2
Holovský, Jakub
3d008a74-9e0e-4cc3-bf89-7a799b4db4ae

Amalathas, Amalraj Peter, Landová, Lucie, Huminiuc, Teodor, Horák, Lukáš, Conrad, Brianna, Polcar, Tomas and Holovský, Jakub (2020) Elucidating the role of TiCl4post-treatment on percolation of TiO2electron transport layer in perovskite solar cells. Journal of Physics D: Applied Physics, 53 (38), [385501]. (doi:10.1088/1361-6463/ab938c).

Record type: Article

Abstract

The ideal electron transport layer of a high performance perovskite solar cell should have good optical transparency, high electron mobility, and an energy level alignment well-matched with the perovskite material. In this work, we investigate the role of TiCl4 post-treatment of the mesoporous TiO2 electron transport layer by varying the concentration of TiCl4 and characterizing optical and electrical properties, charge carrier dynamics, and photovoltaic performance of mesoscopic CH3NH3PbI3 solar cells. It is found that the TiCl4 treatment provides an additional interconnection between the TiO2 particles, leading to better percolation as evident from high resolution cross-section images and chemical maps. This enhances effective electron mobility in the material as well as significantly reduces average sub-bandgap absorption due to defects and electronic disorder determined by photothermal deflection spectroscopy. Moreover, improvement of interfacial contact due to a smoother surface contributes to more efficient charge extraction and suppressed charge recombination and reduced hysteresis. As a result, the optimized device based on TiCl4 post-treated mesoporous TiO2 achieved the highest conversion efficiency of 17.4% compared with 14.1% for the device with pristine mesoporous TiO2.

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Elucidating the role of TiCl(4)post-treatment - Accepted Manuscript
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Accepted/In Press date: 15 May 2020
Published date: 16 September 2020
Keywords: TiCl4 post-treated mesoporous TiO2 electron transport layer, photovoltaic performance, perovskite solar cells

Identifiers

Local EPrints ID: 444767
URI: http://eprints.soton.ac.uk/id/eprint/444767
ISSN: 0022-3727
PURE UUID: eff0cd8f-1fbf-4fc2-b23e-4fbfb85815f7
ORCID for Tomas Polcar: ORCID iD orcid.org/0000-0002-0863-6287

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Date deposited: 04 Nov 2020 17:31
Last modified: 28 Apr 2022 05:37

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Contributors

Author: Amalraj Peter Amalathas
Author: Lucie Landová
Author: Teodor Huminiuc
Author: Lukáš Horák
Author: Brianna Conrad
Author: Tomas Polcar ORCID iD
Author: Jakub Holovský

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