We use cookies to improve your experience and for marketing. Read our cookie policy Manage cookies
Search across reports, market insights, and blog stories.
An international research team has devised a fresh approach to enhancing self-assembled monolayers (SAMs) that serve as hole-transport layers in inverted perovskite solar cells. Termed symmetry-breaking co-assembly (SBC), the technique merges symmetric and asymmetric molecules to curb aggregation and boost surface coverage.
Tom Wu, the corresponding author, explained to pv magazine that instead of creating intricate and expensive asymmetric molecules, the team obtained the advantages of molecular asymmetry by co-assembling a commonly used symmetric SAM (MeO-2PACz) with a straightforward asymmetric conjugated molecule (DTCA). This method, he said, curbs molecular self-aggregation, markedly enhances surface coverage, and betters buried-interface quality.
Wu noted that his group also created a quantitative atomic force microscopy-infrared spectroscopy (AFM-IR) technique to directly gauge SAM coverage at the nanoscale.
He continued that these developments collectively allowed certified efficiencies surpassing 25.6% and outstanding operational stability, offering a practical new framework for interface engineering in perovskite photovoltaics.
The investigators chose MeO-2PACz as the host molecule and contrasted it with two symmetry-breaking co-assemblies that included either 2-thiophenecarboxylic acid (TCA) or dibenzo[b,d]thiophene-4-carboxylic acid (DTCA). The MeO-2PACz, MeO-TCA, and MeO-DTCA formulations were deposited from 0.7 mg/mL isopropanol solutions onto plasma-treated indium tin oxide (ITO) substrates via spin coating at 3,000 rpm for 30 seconds. The samples were subsequently annealed at 100 C for 10 minutes.
Molecular dynamics simulations revealed that DTCA swiftly anchored to the ITO substrate and curbed MeO-2PACz aggregation. AFM-IR measurements indicated surface coverage of 60.6% for MeO-2PACz alone, 62.2% for MeO-TCA, and 82.4% for MeO-DTCA.
The group also assessed MeO-DTCA molar ratios of 3:1, 4:1, and 5:1 and examined DTCA by itself. It pinpointed the 4:1 mixture as the best formulation.
Wu stated that by blending the industry-standard symmetric SAM MeO-2PACz with a small asymmetric molecule (DTCA), they boosted SAM surface coverage by over 30%, as directly quantified using a newly devised AFM-IR analysis method. He expressed astonishment that deliberately breaking molecular symmetry could yield so many advantages for solar cells, resulting in better interface quality, energy conversion efficiency, and operational stability.
The researchers constructed the cell in an inverted configuration. It relied on an indium tin oxide (ITO) substrate, a MeO-DTCA co-assembled SAM as the hole-selective layer (HTL), a perovskite absorber, a phenyl-C61-butyric acid methyl ester (PCBM) electron-transport layer (ETL), a bathocuproine (BCP) buffer layer, and a silver (Ag) electrode.
They clarified that when the surface coverage of co-SAM layers is maximized, the interfacial chemical reaction under electrical stress and the non-radiative recombination loss were effectively curbed, yielding power conversion efficiencies of 26.32% and 25.34% for areas of 0.08 cm2 and 1 cm2, respectively. The encapsulated device kept 93% of its initial efficiency after operating at the maximum power point (MPP) for 1,150 hours.
Wu wrapped up that this study unlocks several promising avenues for future research. He mentioned that the novel strategy is probably relevant to numerous other molecular systems, and the team is keen on building a wider library of symmetry-breaking molecular combinations and setting design rules that connect molecular symmetry, dipole moment, and surface coverage. He also said they intend to apply these molecular design principles to large-area modules and tandem solar cells. Lastly, he noted that their quantitative AFM-IR methodology offers a fresh way to examine ultrathin molecular layers quantitatively, which could aid not just photovoltaics but also other devices involving such molecular layers.
The study, Symmetry-Breaking Co-Assembly of Conjugated Molecules Boosts Perovskite Photovoltaics, appeared in Nature Communications. Contributors hailed from China’s Hong Kong Polytechnic University, Shenzhen University of Advanced Technology, Chinese Academy of Sciences, Northwestern Polytechnical University, and Great Bay University; Australia’s University of New South Wales; the United Kingdom’s University of Surrey; South Korea’s Korea University; and Germany’s Karlsruhe Institute of Technology (KIT).
Making Data-Driven Decisions to Grow Your Business
A Quick Overview of Market Performance
Understanding the Current State of The Market and its Prospects
Finding New Products to Diversify Your Business
Choosing the Best Countries to Establish Your Sustainable Supply Chain
Choosing the Best Countries to Boost Your Export
The Latest Trends and Insights into The Industry
The Largest Import Supplying Countries
The Largest Destinations for Exports
The Largest Producers on The Market and Their Profiles
The Largest Markets And Their Profiles
Instant access. No credit card needed.
Online access to 2M+ reports, dashboards, and tables. Trusted by Fortune 500 teams.
IndexBox, Inc.
2093 Philadelphia Pike #1441
Claymont, DE 19703, USA
Contact us
© 2026 IndexBox, Inc

source