Designing ternary blend bulk heterojunction solar cells with reduced carrier recombination and a fill factor of 77%

Nicola Gasparini, Xuechen Jiao, Thomas Heumueller, Derya Baran, Gebhard J. Matt, Stefanie Fladischer, Erdmann Spiecker, Harald Ade, Christoph J. Brabec, Tayebeh Ameri

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300 Citations (Scopus)


In recent years the concept of ternary blend bulk heterojunction (BHJ) solar cells based on organic semiconductors has been widely used to achieve a better match to the solar irradiance spectrum, and power conversion efficiencies beyond 10% have been reported. However, the fill factor of organic solar cells is still limited by the competition between recombination and extraction of free charges. Here, we design advanced material composites leading to a high fill factor of 77% in ternary blends, thus demonstrating how the recombination thresholds can be overcome. Extending beyond the typical sensitization concept, we add a highly ordered polymer that, in addition to enhanced absorption, overcomes limits predicted by classical recombination models. An effective charge transfer from the disordered host system onto the highly ordered sensitizer effectively avoids traps of the host matrix and features an almost ideal recombination behaviour.

Original languageEnglish
Article number16118
Number of pages9
JournalNature Energy
Publication statusPublished - 8 Sept 2016
Externally publishedYes

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