Multi-junction polymer solar cells

Principles of Multi-Junction Polymer Solar Cells... 

Figure 11.7 Structures of fullerene acceptors used in multi-junction polymer solar cells. References to the publications using these acceptors can be found in Table 11.1.

Table 11.2 Solution processed multi-junction polymer solar cells.

Although multi-junction polymer solar cells are a valid strategy for reaching high PCEs, the increased number of layers that have to be processed on top of eaeh other increases the complexity of the fabrieation process. The first important factor is solvent orthogonality. Each of the layers has to be proeessed from a solution that will not damage or wash away any of the previously deposited layers. For processing on top of a bulk heterojunction polymenfullerene, only a few solvents can be used in praetiee water, aeetone, and aleohols. Typically, the photoactive layers are hydrophobie and this represents an obstacle to the deposition of materials from aqueous solutions beeause of poor wettability. Therefore, extra measures have to be taken such... 

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