Dopant‐Free Bifacial Silicon Solar Cells. Issue 5 (26th March 2021)

• Record Type: Journal Article
• Authors: Lin, Wenjie; Dréon, Julie; Zhong, Sihua; Paratte, Vincent; Antognini, Luca; Cattin, Jean; Liu, Zongtao; Liang, Zongcun; Gao, Pingqi; Shen, Hui; Ballif, Christophe; Boccard, Mathieu
• Is Part Of: Solar RRL. Volume 5:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-26
• Subjects: bifacial solar cells -- carrier-selective contacts -- dopant free solar cells -- partial contacts -- silicon solar cells; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.202000771
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Herein, challenges in the fabrication of full dopant‐free bifacial silicon solar cells are discussed and efficient devices utilizing a MoO3 / indium tin oxide (ITO)/Ag hole‐selective contact and ZnO/LiF x /Al electron‐selective contacts with up to 79% short‐circuit current bifaciality are demonstrated. The ZnO/LiF x /Al rear electron contact features a full‐area ZnO antireflective coating and a LiF x /Al finger contact, allowing sunlight absorption from the back side, thus producing more overall power. The ZnO/LiF x /Al electron contacts with a thinner ZnO layer and a larger contact fraction display a better selectivity and a lower resistance loss. When considering rear‐side irradiance of 0.15 sun, the dopant‐free bifacial solar cell with 60 nm ZnO and 50% LiF x /Al metal contact fraction achieves a 3% estimated output power density improvement compared with its monofacial counterpart (21.0 mW cm −2 compared to 20.3 mW cm −2 ) using the full‐area back contact. Both the efficiency and bifaciality factor of this dopant‐free device are still significantly lower than those of state‐of‐the‐art devices relying on doped‐silicon‐based layers. The required improvement for this technology to become industry‐relevant is discussed. Abstract : Full dopant‐free bifacial silicon solar cells utilizing a MoO3 /ITO/Ag hole contact and ZnO/LiF x /Al electron contacts are first demonstrated. The electron contacts feature a full‐area ZnO antireflective coating and a LiF x /Al finger contact, allowing for bifacial application. The optimized cells with 60 nm ZnO and 50% metal contact fraction achieve an estimated output power density improvement of 0.7 mW cm −2, compared with the monofacial reference cells.