Karpov V.G.,University of Toledo |
Vasko A.,University of Toledo |
Vijh A.,Xunlight Corporation
Applied Physics Letters | Year: 2013
We show that thin film diode structures, such as photovoltaics and light emitting arrays, can undergo zero threshold localized thermal runaway leading to thermal and electrical nonuniformities spontaneously emerging in originally uniform systems. The linear stability analysis is developed for a system of thermally and electrically coupled two discrete diodes, and for a distributed system. These results are verified with numerical modeling that is not limited to small fluctuations. The discovered instability negatively affects the device performance and reliability. It follows that these problems can be mitigated by properly designing the device geometry and thermal insulation. © 2013 AIP Publishing LLC.
Vasko A.C.,University of Toledo |
Vijh A.,Xunlight Corporation |
Karpov V.G.,University of Toledo
Solar Energy | Year: 2014
We present data exhibiting the spontaneous emergence of hot spots in forward biased thin film photovoltaics based on a-Si:H technology. These spots evolve over time, shrinking in their diameter and increasing in temperature up to approximately 300. °C above that of the surrounding area. Our numerical approach explores a system of many identical diodes in parallel connected through the resistive electrode and through thermal connectors, a model which couples electric and thermal processes. The modeling results show that hot spots emerge from a rather large area of nonuniform temperature, then collapse to local entities. Finally, we present a simplified analytical treatment establishing relations between the hot spot parameters. The technological importance of our findings is that they open a venue to improving the large area device performance and reliability by properly scaling the device thickness, substrate material, and thermal insulation. © 2014 Elsevier Ltd.
Xunlight Corporation | Date: 2010-09-14
Xunlight Corporation | Date: 2007-10-07
Photoelectrochemical systems consisting of devices and modules, namely, electrochemical assemblies for splitting water into hydrogen and oxygen and photoelectrochemical modules consisting of photovoltaic cells and electrochemical assemblies, all for producing electricity, but excluding batteries.
Xunlight Corporation | Date: 2010-11-09
A photovoltaic structure is provided. The photovoltaic structure includes a photovoltaic module having a top surface, a bottom surface, and a perimeter. The photovoltaic structure also includes a plurality of flexible tabs attached to the photovoltaic module bottom surface, wherein the plurality of flexible tabs extend beyond the perimeter of the photovoltaic module. A method for mounting a photovoltaic module is also provided.