An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition

Self‐assembling molecules (SAM) have been widely used in inverted perovskite solar cells (PSC) as a hole transfer layer due to nearly lossless charge transfer giving excellent device performance. However, the energy level alignment between SAM‐ and PSC‐related interfaces has not been systematically...

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Main Authors: Jielei Li, Shengwen Li, Bingchen He, Ruifeng Zheng, Yulin Wang, Shi Chen
Format: Article
Language:English
Published: Wiley-VCH 2025-05-01
Series:Advanced Energy & Sustainability Research
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Online Access:https://doi.org/10.1002/aesr.202400336
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author Jielei Li
Shengwen Li
Bingchen He
Ruifeng Zheng
Yulin Wang
Shi Chen
author_facet Jielei Li
Shengwen Li
Bingchen He
Ruifeng Zheng
Yulin Wang
Shi Chen
author_sort Jielei Li
collection DOAJ
description Self‐assembling molecules (SAM) have been widely used in inverted perovskite solar cells (PSC) as a hole transfer layer due to nearly lossless charge transfer giving excellent device performance. However, the energy level alignment between SAM‐ and PSC‐related interfaces has not been systematically studied. Herein, the 2PACz, a typical SAM with the largest dipole moment, is chosen as the model system and is studied by vacuum deposition. It is found that the energy level alignment is determined by the orientation of 2PACz molecules on a different substrate. The molecules are lying down on highly oriented pyrolytic graphite and giving nearly zero interface dipole. On solvent‐cleaned and plasma‐treated indium tin oxide (ITO) substrates, the SAM is vertically assembled with 0.22 and 0.13 eV work function increases, respectively. However, on sputtered ITO, SAM is assembled with upside down orientation, with 0.51 eV work function decrease. The change of orientation is due to strong interaction between oxygen vacancies in ITO substrate and carbazole head group of 2PACz. On perovskite film, SAM also shows a slightly upward orientation with additional passivation of free MA+ ions. Herein, it is confirmed that the energy level alignment of SAM plays an important role in hole extraction.
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spelling doaj-art-b5a1144d59bd4732b86d2c035b2e8c052025-08-20T03:11:22ZengWiley-VCHAdvanced Energy & Sustainability Research2699-94122025-05-0165n/an/a10.1002/aesr.202400336An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum DepositionJielei Li0Shengwen Li1Bingchen He2Ruifeng Zheng3Yulin Wang4Shi Chen5Institute of Applied Physics and Materials Engineering University of Macau Macau SAR 999078 P. R. ChinaInstitute of Applied Physics and Materials Engineering University of Macau Macau SAR 999078 P. R. ChinaInstitute of Applied Physics and Materials Engineering University of Macau Macau SAR 999078 P. R. ChinaInstitute of Applied Physics and Materials Engineering University of Macau Macau SAR 999078 P. R. ChinaInstitute of Applied Physics and Materials Engineering University of Macau Macau SAR 999078 P. R. ChinaInstitute of Applied Physics and Materials Engineering University of Macau Macau SAR 999078 P. R. ChinaSelf‐assembling molecules (SAM) have been widely used in inverted perovskite solar cells (PSC) as a hole transfer layer due to nearly lossless charge transfer giving excellent device performance. However, the energy level alignment between SAM‐ and PSC‐related interfaces has not been systematically studied. Herein, the 2PACz, a typical SAM with the largest dipole moment, is chosen as the model system and is studied by vacuum deposition. It is found that the energy level alignment is determined by the orientation of 2PACz molecules on a different substrate. The molecules are lying down on highly oriented pyrolytic graphite and giving nearly zero interface dipole. On solvent‐cleaned and plasma‐treated indium tin oxide (ITO) substrates, the SAM is vertically assembled with 0.22 and 0.13 eV work function increases, respectively. However, on sputtered ITO, SAM is assembled with upside down orientation, with 0.51 eV work function decrease. The change of orientation is due to strong interaction between oxygen vacancies in ITO substrate and carbazole head group of 2PACz. On perovskite film, SAM also shows a slightly upward orientation with additional passivation of free MA+ ions. Herein, it is confirmed that the energy level alignment of SAM plays an important role in hole extraction.https://doi.org/10.1002/aesr.202400336energy‐level alignmentmolecular orientationperovskite interfaceself‐assembly molecule
spellingShingle Jielei Li
Shengwen Li
Bingchen He
Ruifeng Zheng
Yulin Wang
Shi Chen
An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition
Advanced Energy & Sustainability Research
energy‐level alignment
molecular orientation
perovskite interface
self‐assembly molecule
title An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition
title_full An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition
title_fullStr An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition
title_full_unstemmed An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition
title_short An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition
title_sort energy level alignment study of 2pacz molecule on perovskite device related interfaces by vacuum deposition
topic energy‐level alignment
molecular orientation
perovskite interface
self‐assembly molecule
url https://doi.org/10.1002/aesr.202400336
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