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Solution-processed inorganic bulk nano-heterojunctions and their application to solar cells


In the last decade, solution-processed quantum dot/nanocrystal solar cells have emerged as a very promising technology for third-generation thin-film photovoltaics because of their low cost and high energy-harnessing potential. Quantum dot solar cell architectures developed to date have relied on the use of bulk-like thin films of colloidal quantum dots. Here, we introduce the bulk nano-heterojunction concept for inorganic solution-processed semiconductors. This platform can be readily implemented by mixing different semiconductor nanocrystals in solution and allows for the development of optoelectronic nanocomposite materials with tailored optoelectronic properties. We present bulk nano-heterojunction solar cells based on n-type Bi2S3 nanocrystals and p-type PbS quantum dots, which demonstrate a more than a threefold improvement in device performance compared to their bilayer analogue, as a result of suppressed recombination.

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Figure 1: Bilayer and BNH device structures.
Figure 2: Solar cell characterization of bilayer and BNH devices.
Figure 3: Device physics and carrier lifetime studies in bilayer and BNH devices.
Figure 4: BNH device optimization studies.


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The authors acknowledge financial support from Fundació Privada Cellex Barcelona and the European Union FP7 IRG programme (contract PIRG06-GA-2009-256355). The authors thank N. van Hulst and M. Kuttge for assistance with the transient photoluminescence measurements and for providing access to the focused ion beam (FIB) system for device inspection.

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G.K. supervised the study and wrote the manuscript. A.K.R. fabricated all the devices and contributed to all characterization techniques and data analysis. M.B. synthesized the materials and contributed to material characterization data analysis. L.M. contributed to device characterization and data analysis. F.P.G.A. contributed to data analysis. J.O. contributed to structural characterization and analysis. All authors provided inputs to data analysis, discussed the results and assisted in manuscript preparation.

Corresponding author

Correspondence to Gerasimos Konstantatos.

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The authors declare no competing financial interests.

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Rath, A., Bernechea, M., Martinez, L. et al. Solution-processed inorganic bulk nano-heterojunctions and their application to solar cells. Nature Photon 6, 529–534 (2012).

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