Investigation of p-dopant diffusion in polymer films and bulk heterojunctions: Stable spatially-confined doping for all-solution processed solar cells

• Published in: Organic electronics Vol. 23; no. C; pp. 151 - 157
• Main Authors: Dai, An, Wan, Alan, Magee, Charles, Zhang, Yadong, Barlow, Stephen, Marder, Seth R., Kahn, Antoine
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2015; Elsevier
• Subjects: Diffusion; Doping; Lamination; Molybdenum complex; Polymer; Polymer; Molybdenum complex; Lamination; Diffusion; Doping
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2015.04.023

[Display omitted] •Dopant Mo(tfd-CO2Me)3 diffusivity is studied by SIMS and I–V measurements.•Mo(tfd-CO2Me)3 diffuses extensively at room temperature in pure P3HT films.•Mo(tfd-CO2Me)3 is far more stable at the interface with the P3HT:ICBA films.•Solar cells with laminated doped P3HT film show long-term stability in N2.•No diffusion of dopants is observed under electrical stress. The spatial stability of the soluble p-dopant molybdenum tris[1-(methoxycarbonyl)-2-(trifluoromethyl)-ethane-1,2-dithiolene] in polymer and polymer blend films is investigated via secondary ion mass spectrometry and current–voltage measurements. Bi-layer and tri-layer model structures, P3HT/doped P3HT and P3HT:ICBA/doped P3HT/P3HT:ICBA respectively, are fabricated using soft-contact transfer lamination to study the diffusion of the dopant. While the dopant is very mobile in pure P3HT, it is far more stable at the interface with the P3HT:ICBA bulk heterojunction. Our findings suggest a promising route to achieve spatially-confined doping with long-term stability, leading to hole-collection/injection contacts for all-solution processed polymer devices.