Work

Instability of prevailing small molecule acceptors in organic solar cells toward water/nucleophiles

Year: 2026

Type: article

Abstract: Small molecule acceptors (SMAs) with A-D-A structures have become the key constituents in organic solar cells (OSCs); however, many of them have demonstrated instability toward external factors (including light, heat, water, and oxygen). This work explores the chemical reactivity of the double bond linking the donor (D) and acceptor (A) units in these molecules. Using a model compound, T4CN, constructed by a thiophene (T) and a strong acceptor moiety {2,2′-[1 H -indene-1,3(2 H )-diylidene]dimalononitrile, 4CN}, we show that water can break the double bond. The rate of this reaction depends on the electronic properties and steric hindrance. We found that common SMAs, including ITIC and Y6, react with nucleophiles such as amines and hydroxide, creating unintended products. These reactions can affect device performance and long-term stability. Among the tested materials, Y6, with its β-position side chains, showed the best resistance to water-induced degradation. Our findings highlight key factors affecting SMA stability and offer insights into designing more robust materials for future development of OSCs.

Source: Science Advances

DOI: 10.1126/sciadv.aed7732

Authors: Xiaowei Zhong, Xinzheng Yang, Jiyeon Oh, Xiaosong Li, Wei You

Institutions: University of North Carolina at Chapel Hill, University of Washington

Language: English

Topic: Organic Electronics and Photovoltaics

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $4,500