Evaporated MoOx as general back-side hole collector for solar cells

TitleEvaporated MoOx as general back-side hole collector for solar cells
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2020
AuthorsBobeico, E., Mercaldo L.V., Morvillo P., Usatii I., Noce M.D., Lancellotti L., Sasso C., Ricciardi R., and Veneri P.D.

Substoichiometric molybdenum oxide (MoOx) has good potential as a hole-collecting layer in solar cells. In this paper, we report on the application of ultrathin evaporated MoOx as a hole collector at the back side of two distinct photovoltaic technologies: polymeric and silicon heterojunction (SHJ). In the case of polymer solar cells, we test MoOx as a hole transport layer in devices with inverted architecture. The higher transparency of the MoOx film, compared to the commonly used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), allows an enhanced back reflected light into the photoactive layer, thus boosting the photogeneration, as found from the illuminated J-V and external quantum efficiency (EQE) curves. The higher fill factor (FF) of the MoOx-based device also suggests an improved charge collection efficiency compared to the cells with PEDOT:PSS. As for SHJ solar cells, we show that MoOx offers the means for dopant-free hole collection with both p-type and n-type Si wafers. In the present comparison over planar test structures with Ag back reflecting electrodes, we observe an efficiency gain of approximately 1% absolute against a baseline with a conventional p-type amorphous silicon hole collector. The gain is linked to the increased VOC, which is likely due to the reduced recombination at the Si wafer. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. All right reserved.


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