Publication date: 1st April 2013
ZnO nanowires deposited on the transparent and conducting electrode are often used as the substrates in quantum dot (QD)-sensitized and extremely thin absorber (ETA) solar cells. Such geometry of the deposit offers a high length to diameter ratio and therefore its total surface area might be even 1000 times greater than the geometric surface area of the substrate. In effect, the ZnO nanorods may be covered with a large amount of light harvesting material, which is important in achieving high performance of the device.
Aligned nanorods may be easily obtained by means of electrochemical or hydrothermal methods by two-steps procedure[1]. The first step consists in preparation of a seed layer on the substrate, whereas the second one is the growth of nanostructures. The seeding stage is determining for the quality of the obtained nanorods (their uniformity and ordering). A seed layer for the use in the photovoltaic hybrid cells should cover the whole substrate with a thin and uniform film. A full coverage is necessary to prevent the growth of irregular nanostructures as well as to avoid the electrical shortcuts between cathode and anode after deposition of the hole transporting layer. Additionally, the ZnO underlayer should be transparent to visible light to achieve a high efficiency of back-side illuminated device.
In this work we studied the influence of experimental conditions of seeding (temperature, deposition time) on morphology, optical properties and composition of the seed layers deposited electrochemically on ITO or FTO and in consequence on the quality of ZnO arrays grown on these layers. The seeding was carried out by potentiostatic method in aqueous solution of Zn(NO3)2, whereas ZnO nanorods were formed by hydrothermal synthesis.
The scanning electron microscope (SEM) images of the seeded samples prepared at different deposition charge densities were correlated with their transmittance spectra, XRD results as well as with SEM pictures of ZnO nanorods grown on the seeded substrates. The results of these studies allowed us to determine the optimum conditions of preparation of highly oriented ZnO nanorods arrays for application in QDs and ETA solar cells.
Acknowledgment
The authors thank Polish Ministry of Science and Higher Education for financial support through research project No. N N204 117039.
1. Elias J., Tena-Zaera R., Lévy-Clément C., Electrodeposition of ZnO nanowires with controlled dimensions for photovoltaic applications: Role of buffer layer, Thin Solid Films 2007, 515, 8553. 2. Zarebska K., Kwiatkowski, M., Gniadek, M., Skompska, M., Electrodeposition of Zn(OH)2, ZnO thin films and nanosheet-like zn seed layers and influence of their morphology on the growth of ZnO nanorods. Electrochimica Acta 2013, 98, 255-262.
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.