Interfacial negative capacitance in planar perovskite solar cells: An interpretation based on band theory

Journal Article · Thu Nov 15 00:00:00 EST 2018 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2018.07.015· OSTI ID:22805286

Feng, Yulin ^[1]; Bian, Jiming; Wang, Minhuan ^[1]; Wang, Shi; Zhang, Chunyang ^[2]; Dong, Qingshun ^[3]; Zhang, Bingye ^[1]; Shi, Yantao ^[2]

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1. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024 (China)
2. State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024 (China)
3. Department of Chemistry, Tsinghua University, Beijing (China)

Highlights: • PSCs with different ETL strategies were characterized by EIS measurement under various conditions. • The negative capacitance solely occurred in the moderate frequency region when special conditions are met. • A model based on semiconductor band theory was proposed to interpret the corresponding mechanism. • This achievement provide important insight into the physical mechanism behind the negative capacitance of PSCs. - Abstract: The negative capacitance is a peculiar phenomenon frequently observed in electrochemical impedance spectroscopy (EIS) measurement for perovskite solar cells (PSCs). However, the origin and mechanism of the negative capacitance in PSCs remains ambiguous. Here, planar PSCs with different electron transport layer (ETL) strategies (SnO{sub 2}, TiO{sub 2}, or without ETL) were characterized by EIS in a wide range of frequencies under various conditions. The negative capacitance solely occurred in the moderate frequency region as the perovskite layer directly contacted with the conductive SnO{sub 2}: F (FTO) substrate under illumination and open-circuit conditions. Based on semiconductor band theory, the origin of negative capacitance to the formation of an inversion layer in the perovskite/FTO interface induced by the interfacial energy band over-bent under illumination and open-circuit conditions. Our study provides important insight into the physical mechanism behind the negative capacitance of PSCs.

• OSTI ID: 22805286
• Journal Information: Materials Research Bulletin, Vol. 107; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BAND THEORY
CAPACITANCE
ELECTROCHEMISTRY
ELECTRON TRANSFER
ILLUMINANCE
PEROVSKITE
SEMICONDUCTOR MATERIALS
SOLAR CELLS
SPECTROSCOPY
TIN OXIDES
TITANIUM OXIDES