April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)
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2024 MRS Spring Meeting & Exhibit
EN10.02.04

Ionic Self-Diffusion Approaches: Enhancing Stability and Efficiency in Perovskite Solar Cells through Ion Migration Suppression and Fermi Level Tuning

When and Where

Apr 22, 2024
4:30pm - 4:45pm
Room 347, Level 3, Summit

Presenter(s)

Co-Author(s)

Jihyun Kim1,Ji-Sang Park2,Gee Yeong Kim3,William Jo1

Ewha Womans University1,Sungkyunkwan University2,Korea Institute of Science and Technology3

Abstract

Jihyun Kim1,Ji-Sang Park2,Gee Yeong Kim3,William Jo1

Ewha Womans University1,Sungkyunkwan University2,Korea Institute of Science and Technology3
Lead halide perovskites have garnered attention as potential energy-harvesting materials for optoelectronic devices due to their remarkable photovoltaic properties. Among these, the FA cation demonstrates the most promising performance and attributes to the formamidinium lead triiodide (FAPbI<sub>3</sub>) perovskite, which has a narrow bandgap (E<sub>g</sub>) and great thermal stability. Despite FAPbI<sub>3</sub> perovskite displaying great stability as an absorber layer for perovskite solar cells, issues of device instability persist due to absorbed Pb<sup>2+</sup> or I<sup>&lt;span style="font-size:10.8333px"&gt;-&lt;/span&gt;</sup>at the oxide surface which induced the ion migration of iodine vacancies. This phenomenon generates the hysteresis loop and accelerates degradation rate in photovoltaic performance. In this study, we customized the charge-selective interfaces, revealing the induced adjustment of the Fermi level at the FAPI<sub>3</sub>/SnO<sub>2</sub> junction by ionic diffusion into the bulk. This adjustment enhances charge transport and mitigates ion migration. These findings were confirmed using computational simulations and ultraviolet photoelectron spectroscopy. To understand ion migration mechanism at the FAPbI<sub>3</sub>/SnO<sub>2</sub> interface, we analyze the normalized ionic and electronic conductance as functions of film thickness through D.C polarization measurements. The space charge zone of cation and anion-treated SnO<sub>2</sub> (NH<sub>4</sub><sup>+</sup>-SnO<sub>2</sub> and Cl<sup>-</sup>-SnO<sub>2</sub>) [1], [2] was found to exhibit reduced zones under induced light. Based on our findings, it is evident that interfaces modified with cationic and anionic treatments lead to a decrease in Pb<sup>2+</sup> and I<sup>&lt;span style="font-size:10.8333px"&gt;-&lt;/span&gt;</sup> absorption at the oxide surface. Additionally, these modifications enhance charge transport while significantly minimizing the occurrence of interfacial defects. As a result of this approach, the power conversion efficiency (PCE) increased to 24.38%, and the operational stability of perovskite solar cells (PSCs) was extended to 1600 hours.<br/><br/>[1] J. H. Kim, J. H. Park, Y. H. Kim, and W. Jo, “Improvement of Open-Circuit Voltage Deficit via Pre-treated NH<sub>4</sub><sup>+</sup> Ion Modification of Interface between SnO<sub>2</sub> and Perovskite Solar cells”, Small, 2204173 (2022)<br/><br/>[2] J. H. Kim, Y. S. Kim, H. R. Jung, and W. Jo, “Chlorine-passivation of the ozone-treated SnO<sub>2</sub> thin films: occurrence of oxygen vacancies for manipulation of conducting states and bipolarities in resistive switching”, Applied Surface Science 555, 149625 (2021)

Keywords

photoconductivity

Symposium Organizers

Ivan Mora-Sero, Universitat Jaume I
Michael Saliba, University of Stuttgart
Carolin Sutter-Fella, Lawrence Berkeley National Laboratory
Yuanyuan Zhou, Hong Kong University of Science and Technology

Symposium Support

Silver
Journal of Energy Chemistry

Session Chairs

Tim Kodalle
Yuanyuan Zhou

In this Session