Influences of silicon nanowire morphology on its electro-optical properties and applications for hybrid solar cells

• Published in: Progress in photovoltaics 2013-09, Vol.21 (6), p.1400-1410
• Main Authors: Syu, Hong-Jhang, Shiu, Shu-Chia, Hung, Yung-Jr, Hsueh, Chen-Chih, Lin, Tzu-Ching, Subramani, Thiyagu, Lee, San-Liang, Lin, Ching-Fuh
• Format: Article
• Language: English
• Subjects: Applied sciences; Energy; Exact sciences and technology; hybrid solar cell; metal-assisted etching; Natural energy; organic semiconductor; PEDOT:PSS; Photovoltaic conversion; silicon nanostructure; silicon nanowire; Solar cells. Photoelectrochemical cells; Solar energy
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.2375

ABSTRACT In this paper, we investigate the morphology, optical, and electrical properties of silicon nanowire (SiNW) arrays and their applications on inorganic/organic hybrid solar cells. The SiNW arrays are obtained by two kinds of metal‐assisted chemical etching (MacEtch) processes. One is depositing assisted metal, for example, Ag, by an electron gun evaporator before etching (BE). The other is depositing assisted Ag during the etching (DE) process. The results reveal that BE method MacEtch can produce more uniform and denser SiNW arrays, but the coverage of organic materials to SiNWs is less. In terms of optical properties, the BE method SiNW arrays have higher reflectance than the DE method ones, except the wire length less than 1 µm in the wavelength range less than 500 nm. Regarding the electrical property, the minority‐carrier lifetime is higher for the DE method SiNW arrays because of less surface area of SiNWs. Therefore, the best cell performance happens on the DE method SiNW/organic hybrid solar cell with wire length less than 1 µm. The short‐circuit current density (Jsc) is 28.55 mA/cm2, open‐circuit voltage (Voc) is 0.524 V, and power conversion efficiency (PCE) is 9.56%. Copyright © 2013 John Wiley & Sons, Ltd. SiNW/PEDOT:PSS hybrid solar cells with wire arrays formed by depositing assisted metal during the etching process (DE method) have a better cell performance of PCE of 9.56%, Jsc of 28.55 mA/cm2, and Voc of 0.524 V. However, cells with wire arrays formed by depositing assisted metal before the etching process (BE method) have a worse cell performance of PCE of 8.66%, Jsc of 26.38 mA/cm2, and Voc of 0.517 V.