Enhanced Device Performance with Passivation of the TiO2 Surface Using a Carboxylic Acid Fullerene Monolayer for a SnPb Perovskite Solar Cell with a Normal Planar Structure

Kengo Hamada; Ryo Tanaka; Muhammad Akmal Kamarudin; Qing Shen; Satoshi Iikubo; Takashi Minemoto; Kenji Yoshino; Taro Toyoda; Tingli Ma; Dong-Won Kang; Shuzi Hayase

doi:10.1021/acsami.0c01411

Enhanced Device Performance with Passivation of the TiO₂ Surface Using a Carboxylic Acid Fullerene Monolayer for a SnPb Perovskite Solar Cell with a Normal Planar Structure

ACS Appl Mater Interfaces. 2020 Apr 15;12(15):17776-17782. doi: 10.1021/acsami.0c01411. Epub 2020 Apr 4.

Authors

Kengo Hamada^{1

2}, Ryo Tanaka¹, Muhammad Akmal Kamarudin², Qing Shen², Satoshi Iikubo¹, Takashi Minemoto³, Kenji Yoshino⁴, Taro Toyoda², Tingli Ma¹, Dong-Won Kang⁵, Shuzi Hayase^{1

2}

Affiliations

¹ Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu-shi, Fukuoka-ken 808-0196, Japan.
² Faculty of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan.
³ Department of Electrical and Electronic Engineering, Faculty of Science and Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan.
⁴ Department of Electrical and Electronic Engineering, Miyazaki University, 1-1 Gakuen Kibanadai Nishi, Miyazaki 889-2192 Japan.
⁵ School of Energy Systems Engineering, Chung-Ang University, Seoul 06974, South Korea.

PMID: 32204584
DOI: 10.1021/acsami.0c01411

Abstract

Research on tin-lead (SnPb) perovskite solar cells (PSCs) has gained popularity in recent years because of their low band gap, which could be applied to tandem solar cells. However, most of the work is based on inverted PSCs using PEDOT:PSS as the hole-transport layer as normal-structure PSCs show lower efficiency. In this work, the reason behind the low efficiency of normal-structure SnPb PSCs is elucidated and surface passivation has been tested as a method to overcome the problem. In the case of normal PSCs, at the interface between the titania layer and SnPb perovskite, there are many carrier traps observed originating from Ti-O-Sn bonds. In order to avoid the direct contact between titania and the SnPb perovskite layer, the titania surface is passivated with carboxylic acid C₆₀ resulting in an efficiency increase from 5.14 to 7.91%. This will provide a direction of enhancing the efficiency of the normal-structure SnPb PSCs through heterojunction engineering.

Keywords: interface; lead; passivation; perovskite solar cells; tin; titania; trap density.