Terminations Determine Energy-Level Alignment of Perovskite Buried Interfaces

Yang Li; Junnan Guo; Jihua Tan; Ping Man; Shiang Li; Zixin Zeng; Thuc Hue Ly; Sai-Wing Tsang; Xinhui Lu; Weikang Wu; Chun-Sing Lee; Zhiqiang Guan

doi:10.1002/adma.202506747

Terminations Determine Energy-Level Alignment of Perovskite Buried Interfaces

Yang Li (Co-first Author), Junnan Guo (Co-first Author), Jihua Tan, Ping Man, Shiang Li, Zixin Zeng, Thuc Hue Ly, Sai-Wing Tsang, Xinhui Lu, Weikang Wu^*, Chun-Sing Lee^*, Zhiqiang Guan^*

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

Abstract

The “substrate-effect”, where the semiconduction type of perovskite changes according to that of the substrate is a widely-reported, but so far not fully understood phenomenon in the field of perovskite. The main challenge lies in the difficulty of probing and comprehending the electronic properties of perovskite buried interfaces. Here, through broadly investigating 20 buried interfaces formed between different perovskites and organic hole or electron transport materials (HTMs or ETMs), it is revealed that the substrate-effect originates from the distinct energy-level alignments at HTM or ETM substrates. Experimental and theoretical studies reveal that this difference stems from varying proportions of two perovskite terminations, which are determined by the interaction between substrates and perovskite crystals. With such mechanism, the semiconduction type of perovskite by controlling the proportion of surface terminations is successfully tuned. These findings provide new insights into optimizing device performance through termination engineering. © 2025 Wiley-VCH GmbH.

Original language	English
Article number	e06747
Number of pages	11
Journal	Advanced Materials
Volume	37
Issue number	40
Online published	21 Jul 2025
DOIs	https://doi.org/10.1002/adma.202506747
Publication status	Published - 9 Oct 2025

Funding

Y.L. and J.G. contributed equally to this work. This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. CityU 11303923). W.W. thanks support from Shandong Provincial Natural Science Foundation (Grant No. ZR2023QA012).

Research Keywords

buried interface
energy-level alignment
perovskite
termination
ultraviolet photoelectron spectroscopy

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title = "Terminations Determine Energy-Level Alignment of Perovskite Buried Interfaces",

abstract = "The “substrate-effect”, where the semiconduction type of perovskite changes according to that of the substrate is a widely-reported, but so far not fully understood phenomenon in the field of perovskite. The main challenge lies in the difficulty of probing and comprehending the electronic properties of perovskite buried interfaces. Here, through broadly investigating 20 buried interfaces formed between different perovskites and organic hole or electron transport materials (HTMs or ETMs), it is revealed that the substrate-effect originates from the distinct energy-level alignments at HTM or ETM substrates. Experimental and theoretical studies reveal that this difference stems from varying proportions of two perovskite terminations, which are determined by the interaction between substrates and perovskite crystals. With such mechanism, the semiconduction type of perovskite by controlling the proportion of surface terminations is successfully tuned. These findings provide new insights into optimizing device performance through termination engineering. {\textcopyright} 2025 Wiley-VCH GmbH.",

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author = "Yang Li and Junnan Guo and Jihua Tan and Ping Man and Shiang Li and Zixin Zeng and Ly, {Thuc Hue} and Sai-Wing Tsang and Xinhui Lu and Weikang Wu and Chun-Sing Lee and Zhiqiang Guan",

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AU - Li, Yang

AU - Guo, Junnan

AU - Tan, Jihua

AU - Man, Ping

AU - Li, Shiang

AU - Zeng, Zixin

AU - Ly, Thuc Hue

AU - Tsang, Sai-Wing

AU - Lu, Xinhui

AU - Wu, Weikang

AU - Lee, Chun-Sing

AU - Guan, Zhiqiang

PY - 2025/10/9

Y1 - 2025/10/9

N2 - The “substrate-effect”, where the semiconduction type of perovskite changes according to that of the substrate is a widely-reported, but so far not fully understood phenomenon in the field of perovskite. The main challenge lies in the difficulty of probing and comprehending the electronic properties of perovskite buried interfaces. Here, through broadly investigating 20 buried interfaces formed between different perovskites and organic hole or electron transport materials (HTMs or ETMs), it is revealed that the substrate-effect originates from the distinct energy-level alignments at HTM or ETM substrates. Experimental and theoretical studies reveal that this difference stems from varying proportions of two perovskite terminations, which are determined by the interaction between substrates and perovskite crystals. With such mechanism, the semiconduction type of perovskite by controlling the proportion of surface terminations is successfully tuned. These findings provide new insights into optimizing device performance through termination engineering. © 2025 Wiley-VCH GmbH.

AB - The “substrate-effect”, where the semiconduction type of perovskite changes according to that of the substrate is a widely-reported, but so far not fully understood phenomenon in the field of perovskite. The main challenge lies in the difficulty of probing and comprehending the electronic properties of perovskite buried interfaces. Here, through broadly investigating 20 buried interfaces formed between different perovskites and organic hole or electron transport materials (HTMs or ETMs), it is revealed that the substrate-effect originates from the distinct energy-level alignments at HTM or ETM substrates. Experimental and theoretical studies reveal that this difference stems from varying proportions of two perovskite terminations, which are determined by the interaction between substrates and perovskite crystals. With such mechanism, the semiconduction type of perovskite by controlling the proportion of surface terminations is successfully tuned. These findings provide new insights into optimizing device performance through termination engineering. © 2025 Wiley-VCH GmbH.

KW - buried interface

KW - energy-level alignment

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KW - ultraviolet photoelectron spectroscopy

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DO - 10.1002/adma.202506747

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JO - Advanced Materials

JF - Advanced Materials

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Terminations Determine Energy-Level Alignment of Perovskite Buried Interfaces

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GRF: Investigation on Electronic Structures of Charge-Transporting Layer/Perovskite Interfaces Using in-situ Ultraviolet Photoemission Spectroscopy

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Terminations Determine Energy-Level Alignment of Perovskite Buried Interfaces

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GRF: Investigation on Electronic Structures of Charge-Transporting Layer/Perovskite Interfaces Using in-situ Ultraviolet Photoemission Spectroscopy

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