Title: Junction Quality of SnO₂-Based Perovskite Solar Cells Investigated by Nanometer-Scale Electrical Potential Profiling

Abstract

Electron-selective layers (ESLs) and hole-selective layers (HSLs) are critical in high-efficiency organic-inorganic lead halide perovskite (PS) solar cells for charge-carrier transport, separation, and collection. We developed a procedure to assess the quality of the ESL/PS junction by measuring potential distribution on cross-section of SnO₂-based perovskite solar cells using Kelvin probe force microscopy. Using the potential profiling, we compared three types of cells made of different ESLs but otherwise having identical device structure: cells with PS deposited directly on bare fluorine-doped SnO₂ (FTO)-coated glass; cells with an intrinsic SnO₂ thin layer on the top of FTO as an effective ESL; and cells with the SnO2 ESL and adding a self-assembled monolayer (SAM) of fullerene. The results reveal two major potential drops or electric fields at the ESL/PS and PS/HSL interfaces. The electric-field ratio between the ESL/PS and PS/HSL interfaces increased in devices as follows: FTO < SnO₂-ESL < SnO₂+SAM; this sequence explains the improvements of fill factor (FF) and open-circuit voltage (V_oc). The improvement of FF from the FTO to SnO₂-ESL cells may result from the reduction in voltage lose at the PS/HSL back interface and the improvement of V_oc from the prevention of hole recombination at the ESL/PS front interface.more » The further improvements with adding a SAM is caused by the defect passivation at the ESL/PS interface, and hence, improvement of the junction quality. Furthermore, these nanoelectrical findings suggest possibilities for improving the device performance by further optimizing the SnO2-based ESL material quality and the ESL/PS interface.« less

Authors:

Xiao, Chuanxiao ^[1]; Wang, Changlei ^[2]; Ke, Weijun  ^[2];

• Search DOE PAGES for author "Ke, Weijun"
• Search DOE PAGES for ORCID "0000-0003-2600-5419"

Gorman, Brian P. ^[3]; Ye, Jichun ^[4]; Jiang, Chun -Sheng  ^[5];

• Search DOE PAGES for author "Jiang, Chun -Sheng"
• Search DOE PAGES for ORCID "0000-0003-0230-7500"

Yan, Yanfa  ^[2];

• Search DOE PAGES for author "Yan, Yanfa"
• Search DOE PAGES for ORCID "0000-0003-3977-5789"

Al-Jassim, Mowafak M. ^[5]

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+ Show Author Affiliations

1. National Renewable Energy Lab. (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)
2. The Univ. of Toledo, Toledo, OH (United States)
3. Colorado School of Mines, Golden, CO (United States)
4. Chinese Academy of Science, Zhejiang Province (China)
5. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:

Fri Oct 13 00:00:00 EDT 2017

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1404880

Report Number(s):

NREL/JA-5K00-67770
Journal ID: ISSN 1944-8244

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Volume: 9; Journal Issue: 44; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Kelvin probe force microscopy; junction quality; perovskite solar cell; electron-selective layer; interface; nanometer-scale; potential profile