Fast-Growth Polymer: Fullerene Bulk-Heterojunction Thin Films for Efficient Organic Photovoltaics

• Published in: Nanomaterials (Basel, Switzerland) Vol. 14; no. 6; p. 502
• Main Authors: Chung, Daewon, Balamurugan, Chandran, Park, Byoungwook, Lee, Hyeonryul, Cho, Ilhyeon, Yoon, Chaerin, Park, Soyeon, Jo, Yong-Ryun, Jeon, Joonhyeon, Hong, Soonil, Kwon, Sooncheol
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 11.03.2024; MDPI
• Subjects: Acceptor materials; Aluminum; Analysis; bulk heterojunction; Chemical processes; Composite materials; Contact angle; Dielectric films; Efficiency; Electrons; Energy; Evaporation; Fullerenes; Glass substrates; Growth kinetics; Heterojunctions; homogeneous morphology; Identification and classification; Interfaces; Methods; Microscopy; Morphology; Nanoparticles; organic solar cells; P3HT (Poly-3-hexylthiophene); PCBM ([6,6]-phenyl-C61-butyric acid methyl ester); Performance evaluation; Phase separation; Photovoltaic cells; Photovoltaics; Polymers; Properties; Solar cells; Solvents; Spinning (materials); Substrates; Surface energy; Surface properties; Thin films; South Korea; organic solar cells; PCBM ([6,6]-phenyl-C61-butyric acid methyl ester); P3HT (Poly-3-hexylthiophene); bulk heterojunction; homogeneous morphology
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano14060502

The bulk-heterojunction (BHJ) system that uses a π-conjugated polymer as an electron donor, and a fullerene derivative as an electron acceptor, is widely used in organic solar cells (OSCs) to facilitate efficient charge separation and extraction. However, the conventional BHJ system still suffers from unwanted phase segregation caused by the existence of significant differences in surface energy between the two BHJ components and the charge extraction layer during film formation. In the present work, we demonstrate a sophisticated control of fast film-growth kinetics that can be used to achieve a uniform distribution of donor and acceptor materials in the BHJ layer of OSCs without undesirable phase separation. Our approach involves depositing the BHJ solution onto a spinning substrate, thus inducing rapid evaporation of the solvent during BHJ film formation. The fast-growth process prevents the fullerene derivative from migrating toward the charge extraction layer, thereby enabling a homogeneous distribution of the fullerene derivative within the BHJ film. The OSCs based on the fast-growth BHJ thin film are found to exhibit substantial increases in J , fill factor, and a PCE up to 11.27 mA/cm , 66%, and 4.68%, respectively; this last value represents a remarkable 17% increase in PCE compared to that of conventional OSCs.