Bulk heterojunctions morphology

V. Gernigon, P. Leveque, C. Brochon, J.-N. Audinot, N. Leclerc, R. Bechara, F. Richard, T. Heiser, G. Hadziioannou, FuUerene-Grafted Block Copolymers Used as Compatibilizer in P3HT/PCBM Bulk Heterojunctions Morphology and Photovoltaic Performances. Eur. Phys. J. Appl. Phys. 2011,56,34107. 

V. Gernigon, et al., Fullerene-grafted block copolymers used as compati-bilizer in P3HT/PCBM bulk heterojunctions Morphology and photovoltaic performances. The European Physical Journal - Applied Physics, 2011. 56(03). 

However, bulk heterojunction morphologies are described by much more than just a characteristic domain size. Further morphological features which may determine the performance of a bulk heterojunction OPV include the purity of the domains, the interfaces between these domains, the connectivity of the domains, and more. Lyons et al. [18] tried to deconvolve the effects of these morphological features by comparing simulation results on a range of morphologies with different characteristics, namely impure domains with diffuse interfaces (Cl), pure domains with diffuse interfaces (DII), and pure domains with abrupt interfaces (SII), as shown in Fig. 6. 

Relating Processing Conditions to Bulk-Heterojunction Morphology. 190... 

Consequently, interpenetrating phase-separated D/A network composites, i.e. bulk heterojunction , would appear to be ideal photovoltaic materials [5]. By controlling the morphology of the phase separation into an interpenetrating network, one can achieve a high interfacial area within a bulk material. Since any point in the composite is within a few nanometers of a D/A interface, such a composite is a bulk D/A heterojunction material. If the network in a device is bicontinuous, as shown in Figure 15-26, the collection efficiency can be equally efficient. 

Giridharagopal R, Ginger DS (2010) Characterizing morphology in bulk heterojunction organic photovoltaic systems. J Phys Chem Lett 1 1160... 

The network morphology of the phase-separated composite material for enhanced transport and carrier generation. Absorption and mobility of charge carriers has to be maximized within the different components of the bulk heterojunction. 

Hoppe H, Niggemann M, Winder C, Kraut J, Hiesgen R, Hinsch A, Meissner D, Sariciftci NS (2004) Nanoscale morphology of conjugated polymer/fullerene based bulk-heterojunction solar cells. Adv Fund Mater 14 1005... 

Savenije, T.J. et ah. The effect of thermal treatment on the morphology and charge carrier dynamics in a polythiophene-fullerene bulk heterojunction, Adv. Fund. Mater. 15, 1260-1266, 2005. 

D. Vanderzande, and J.V. Manca, High-resolution morphological and electrical characterisation of organic bulk heterojunction solar cells by scanning probe microscopy. Prog. 

Innovations in materials science and technology have provided promising strategies to realize a high photovoltaic performance. Besides the intrinsic properties of photoactive polymer materials, morphology is also critical in bulk heterojunction polymer solar cells. 

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