On the Importance of Morphology Control in Polymer Solar Cells

• Published in: Macromolecular rapid communications. Vol. 31; no. 21; pp. 1835 - 1845
• Main Authors: van Bavel, Svetlana, Veenstra, Sjoerd, Loos, Joachim
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.11.2010; WILEY‐VCH Verlag; Wiley
• Subjects: Application fields; Applied sciences; bulk heterojunction; Devices; electron tomography; Energy; Exact sciences and technology; Heterojunctions; Morphology; Nanocomposites; Nanomaterials; Nanostructure; Natural energy; Photovoltaic cells; Photovoltaic conversion; Polymer industry, paints, wood; polymer solar cells; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Technology of polymers; films; bulk heterojunction; Morphology; Polymer; Property structure relationship; polymer solar cells; Review; Surface topography; Organic solar cells; electron tomography; Electrical characteristic; Heterojunction
• ISSN: 1022-1336; 1521-3927; 1521-3927
• DOI: 10.1002/marc.201000080

Nanostructured polymer‐based solar cells (PSCs) have emerged as a promising low‐cost alternative to conventional inorganic photovoltaic devices and are now a subject of intensive research both in academia and industry. For PSCs to become practical efficient devices, several issues should still be addressed, including further understanding of their operation and stability, which in turn are largely determined by the morphological organisation in the photoactive layer. The latter is typically a few hundred nanometres thick film and is a blend composed of two materials: the bulk heterojunction consisting of the electron donor and the electron acceptor. The main requirements for the morphology of efficient photoactive layers are nanoscale phase segregation for a high donor/acceptor interface area and hence efficient exciton dissociation, short and continuous percolation pathways of both components leading through the layer thickness to the corresponding electrodes for efficient charge transport and collection, and high crystallinity of both donor and acceptor materials for high charge mobility. In this paper, we review recent progress of our understanding on how the efficiency of a bulk heterojunction PSC largely depends on the local nanoscale volume organisation of the photoactive layer. The volume morphology of the bulk heterojunction photoactive layer determines the performance of polymer solar cells. In this paper the critical parameters are discussed influencing morphology creation and thus the ultimate light conversion efficiency for a given electron acceptor and donor system.