Iodine‐Stabilized Organic Nanoparticle Dispersions for the Fabrication of 10% Efficient Non‐Fullerene Solar Cells

• Published in: Advanced energy materials Vol. 13; no. 6
• Main Authors: Manger, Felix, Fischer, Karen, Marlow, Philipp, Röhm, Holger, Sprau, Christian, Colsmann, Alexander
• Format: Journal Article
• Language: English
• Published: 01.02.2023
• Subjects: electrical doping; nanoparticles; nanoprecipitation; non‐fullerene acceptors; organic solar cells
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202202820

High‐performance organic solar cells are deposited from eco‐friendly semiconductor dispersions by applying reversible electrostatic stabilization while omitting the need for stabilizing surfactants. The addition of iodine fosters the oxidation (p‐doping) of the light‐harvesting polymer, effectively promoting the electrostatic repulsion of the nanoparticles and hence the colloidal stability of the respective dispersions. The oxidation of polymers with iodine is reversible: after thin‐film deposition and after thermal evaporation of the iodine, the corresponding polymer:non‐fullerene solar cells yield power conversion efficiencies of up to 10.6%. Non‐fullerene organic solar cells with power conversion efficiencies of more than 10% are fabricated from surfactant‐free nanoparticle dispersions. Iodine is used to enhance the colloidal stability of the dispersions by charge transfer. After thin‐film deposition, the volatile iodine evaporates from the light‐harvesting layer without compromising the solar cell performance.