Title:	14% Efficiency Ultrathin Silicon Solar Cells with Improved Infrared Light Management Enabled by Hole-Selective Transition Metal Oxide Full-Area Rear Passivating Contacts
Author(s):	H. Nasser, M. Zolfaghari Borra, E.H. Çiftpinar, B. Eldeeb, R. Turan
Keywords:	Passivating contacts, Hole Selective Contact, Ultrathin c-Si, Dopant-Free, Asymetric Heterocontacts
Topic:	Silicon Materials and Cells
Subtopic:	Thin Film and Foil-Based Si Cells
Event:	38th European Photovoltaic Solar Energy Conference and Exhibition
Session:	2EO.3.4
Pages:	208 - 211
ISBN:	3-936338-78-7
Paper DOI:	10.4229/EUPVSEC20212021-2EO.3.4
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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We report efficient 22.5 µm-thick p-type crystalline silicon (c-Si) solar cells with hole-selective transition metal oxide (TMO) layers stacked with silver as full-area rear contacts. The TMO layers, namely molybdenum oxide (MoOx), vanadium oxide (V2Ox), and tungsten oxide (WOx), are prepared by thermal evaporation at room temperature. These films have large work function relative to p-type c-Si creating strong accumulation layer at the interface with high hole concentration which reduces the interfacial recombination current density (J0) and contact resistivity (c). Among the TMO p-type Si contacts considered, the MoOx/p-type Si contact achieves the lowest c of ~27 mΩ.cm2 relative to WOx/p-type Si (~42 mΩ.cm2) and V2Ox/p-type Si (~190 mΩ.cm2). On the other hand, V2Ox/p-type Si contact yields the lowest J0 of 65.5 fA/cm2 compared to MoOx (79.5 fA/cm2) and WOx (264.5 fA/cm2 ) based p-type Si contacts. Furthermore, the presence of TMO/Ag contact at the rear resulted in an enhanced external quantum efficiency (EQE) response at long wavelengths compared to reference solar cells with Al at the rear. The champion solar cell with efficiency value reaching 14% was realized from the solar cell with MoOx/Ag at the rear.