Improvement of the SiOx Passivation Layer for High-Efficiency Si/PEDOT:PSS Heterojunction Solar Cells

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• 作者：Jiang Sheng ; Ke Fan ; Dan Wang ; Can Han ; Junfeng Fang ; Pingqi Gao ; Jichun Ye
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：September 24, 2014
• 年：2014
• 卷：6
• 期：18
• 页码：16027-16034
• 全文大小：421K
• ISSN：1944-8252

文摘

Interfacial properties currently hinder the performance of Si/organic heterojunction solar cells for an alternative to high-efficiency and low-cost photovoltaics. Here, we present a simple and repeatable wet oxidation method for developing the surface passivation layer, SiO_x, on the Si surface for the fabrication of high-efficiency Si/poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) heterojunction solar cells. The uniform and dense SiO_x thin layer introduced by the oxidizing aqueous solution of H₂O₂ or HNO₃ provided the better surface passivation and stronger wettability of the Si surface, compared to those in the native oxide case. These two types of progress helped create a lower defect density at the Si/PEDOT:PSS interface and thus a high-quality p鈥搉 junction with a lower interface recombination velocity. As a result, the HNO₃-oxidized device displayed better performance with a power conversion efficiency (PCE) of 11%, representing a 28.96% enhancement from the PCE of 8.53% in the native oxide case. The effects on the performance of the Si/PEDOT:PSS hybrid solar cells of the wet oxidation treatment procedure, including the differences in surface roughness and wettability of the Si substrate, the quality and thickness of the SiO_x, etc., were explored extensively. Such a simple and controllable oxidizing treatment could be an effective way to promote the interfacial properties that are an important cornerstone for more efficient Si/organic hybrid solar cells.

Keywords:

Si/PEDOT:PSS; heterojunction solar cells; wet oxidation; SiO_x passivation; interface modification