Hexagonal Array Patterned PMMA Buffer Layer for Efficient Hole Transport and Tailored Interfacial Properties of FTO-Based Organic Solar Cells

• Published in: Macromolecular research Vol. 26; no. 12; pp. 1173 - 1178
• Main Authors: Roh, Seung Hun, Kim, Jung Kyu
• Format: Journal Article
• Language: English
• Published: Seoul The Polymer Society of Korea 01.12.2018; Springer Nature B.V; 한국고분자학회
• Subjects: Arrays; Buffer layers; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Energy conversion efficiency; Fluorine; Heavy metals; Indium tin oxides; Interfacial properties; Morphology; Nanochemistry; Nanotechnology; Organic chemistry; Photovoltaic cells; Physical Chemistry; Polymer Sciences; Polymethyl methacrylate; Polystyrene resins; Soft and Granular Matter; Solar cells; Substrates; Surface properties; Surface stability; 고분자공학; organic solar cells; poly(methyl methacrylate); ITO free; nanoimprinting lithography; PEDOT:PSS
• ISSN: 1598-5032; 2092-7673
• DOI: 10.1007/s13233-018-6152-7

Organic photovoltaics (OPVs) have attracted substantial attention due to their solution-based low-cost processability. However, challenges remain with the OPV module in terms of reducing the process cost and enhancing the stability. For example, more than half of the process cost can be consumed by the indium tin oxide (ITO) substrate. Further, the indium dopant can be easily diffused out of ITO, thereby deteriorating the device stability. Here, a hexagonal array patterned poly(methyl methacrylate) (PMMA) buffer layer is introduced between the fluorine doped tin oxide (FTO) substrate and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) so as to achieve ITO-free-OPVs with enhanced power conversion efficiency and long-term stability. The rough surface property of FTO is amended by the patterned PMMA layer via nanoimprinting lithography using a rigiflex imprinting mold with the hexagonal pillar pattern array. The surface morphology and film properties of the PMMA layer are tailored by the optimized O 2 -plasma treatment. Consequently, the patterned PMMA/FTO ameliorates the morphology and interfacial properties of the PEDOT:PSS layer, which contributes to enhancing the device performance. Over 8% higher power conversion efficiency is achieved in comparison to OPVs with bare ITO. In addition, the patterned PMMA/FTO prevents the diffusion of heavy metal components, thereby higher stability is achieved in comparison to OPVs with bare ITO.