Phenothiazine-based self-assembled monolayers for efficient tin perovskite solar cells with Co-cations
Journal
Journal of Materials Chemistry A
Journal Volume
13
Journal Issue
13
Start Page
9252
End Page
9264
ISSN
2050-7488
2050-7496
Date Issued
2025-02-17
Author(s)
Atika Abid
Arulmozhi Velusamy
Shakil N. Afraj
Waqas Pervez
Ting-Yu Su
Shao-Huan Hong
Ming-Chou Chen
Eric Wei-Guang Diau
Abstract
We developed three self-assembled monolayer (SAM) molecules, PTz2 (1), PTz (2) and PTzBr (3), and investigated the mixing of guanidinium (GA) and methylammonium (MA) cations at the A-site, alongside formamidinium (FA), to create mixed cations during the deposition of the tin perovskite layer onto phenothiazine-based SAM-coated ITO substrates using a two-step fabrication method. This study reveals the synergy between the larger ammonium-like GA cations and FA, resulting in the structure FA0.75GA0.25SnI3 that inhibits moisture diffusion into the perovskite layer to provide ideal grain passivation. Consequently, the PTzBr (3) SAM-based device showed the best performance, achieving a power conversion efficiency of 7.8% and showing negligible hysteresis effects. Additionally, the PTzBr (3) device demonstrated remarkable long-term storage stability, retaining about 80% of its initial efficiency for over 4000 h without encapsulation, and remaining stable for 9 h under one-sun illumination. The thermal, morphological, optical, electrochemical, charge recombination, and single-crystal properties of the phenothiazine-based SAMs (1-3) were also investigated to understand the superior performance of the PTzBr (3) device.
Publisher
Royal Society of Chemistry (RSC)
Type
journal article