ZnO/Al2O3 core/shell nanorods array as excellent anti-reflection layers on silicon solar cells
Journal
Materials Chemistry and Physics
Journal Volume
180
Pages
195-202
Date Issued
2016
Author(s)
Abstract
A simple, low-temperature hydrothermal method and atomic layer deposition (ALD) were used to fabricate ZnO nanostructures as subwavelength-structure antireflection layers (SWS ARLs) on Si solar cells. ZnO seed layers with wafer-scale uniformity were prepared, and ALD was used to reproduce two types of ZnO-based structures, nanorod arrays (NRAs) and nanotip arrays (NTAs). The study examined diammonium phosphate concentrations during growth, conducted simulations based on three-dimensional finite-difference time-domain and reflection analyses, performed X-ray diffractometer, field-emission scanning electron microscope, and high-resolution transmission electron microscope characterizations, measured total reflectance spectra by using a spectrophotometer with integrated spheres, and ran solar simulations to determine the efficiency of the Si solar cells. Coating the ZnO NTAs on the Si solar cells yielded a low total reflectance over a broad band range and produced omnidirectional light scattering on the cells, causing incident light to have a shallow penetration depth near the p–n junction and leading to an increase in short current density (Jsc). Coating the ZnO NTAs with an Al2O3 shell induced continuous variation in the refractive index, further decreasing the total reflectance to approximately 5.5%, and protected the ZnO NTAs from the harmful acidic environment. Significantly increasing the Jsc and η levels of the Si solar cells, the Al2O3@ZnO-NTA antireflection structure produced a high efficiency of 17.79%. Its superior performance, including low and wideband reflectance, a low process temperature, and a significant increase in efficiency, indicates the potential of this antireflective structure for enhancing solar cell efficiency in photovoltaic devices. © 2016 Elsevier B.V.
Subjects
Light scattering; Optical properties; Oxides; Surface properties
SDGs
Other Subjects
Aluminum; Aluminum coatings; Atomic layer deposition; Coatings; Crystal atomic structure; Efficiency; Finite difference time domain method; Light scattering; Nanorods; Nanotips; Optical properties; Oxides; Reflection; Refractive index; Scanning electron microscopy; Semiconductor junctions; Silicon; Silicon wafers; Slow wave structures; Solar cells; Solar power generation; Surface properties; Temperature; Time domain analysis; Zinc oxide; Anti-reflection structures; Antireflective structure; Field emission scanning electron microscopes; Low process temperature; Low-temperature hydrothermal methods; Solar cell efficiencies; Sub-wavelength structures; Three dimensional finite difference time domains; Silicon solar cells
Type
journal article