Morphological Device Model for Organic Bulk Heterojunction Solar Cells

• Published in: Nano letters Vol. 9; no. 8; pp. 3032 - 3037
• Main Authors: Maturová, K, van Bavel, S. S, Wienk, M. M, Janssen, R. A. J, Kemerink, M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12-08-2009
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Energy; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Natural energy; Photovoltaic conversion; Physics; Solar cells. Photoelectrochemical cells; Solar energy; Specific materials; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Solar cell; Nanometer scale; Voltage current curve; Electronic conductivity; Phase separation; Fullerene polymer; Fullerenes; Nanostructure; Heterojunction
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/nl901511a

We present a numerical model for calculating current-voltage characteristics of polymer:fullerene bulk hetrojunction solar cells at different degrees of nanoscale phase separation. We show that the short-circuit current enhancement with finer phase separation is due to a reduction in bimolecular recombination caused by lateral movement of photogenerated electrons to the fullerene-rich phase. At high bias, vertical electron transport is enhanced and lateral movement is reduced, causing a significant field-dependent carrier extraction for coarse morphologies.