Jose Ruben Gutierrez

• PhD
• University of the Basque Country

Albedo estimation is an essential input parameter for bifacial PV modules. However, there was no clear agreement on which albedo values should be used and how they should be measured, either with satellite measurements or using onsite measurements which can be obtained from nearby meteorological stations. Since long-term measurements are not always...

This work features to simulate the effect of local defects in crystalline silicon solar cells by means of the 2D distributed model of the cell using the electronic simulation tool LTSpice®. For that, starting from locally laser damaged cells with known lumped characteristic parameters, the distributed parameters are obtained. The horizontal voltage...

Fluctuations at surface albedo measurements are widely known because of seasonality, weather, and heterogeneity on the ground, among others. Additionally, even some studies provide an analysis of cloud enhancement (CE) and albedo enhancement (AE) due to sky cloudy conditions. In this paper, we report about surface albedo long-term changes under dif...

Fluctuations at surface albedo measurements are widely known because of seasonality, weather, and heterogeneity on the ground, among others. Additionally, even some studies provide an analysis of cloud enhancement (CE) and albedo enhancement (AE) due to sky cloudy conditions. In this paper, we report about surface albedo long-term changes under dif...

Texturing is the most common technology used in the reduction of optical losses in monocrystalline silicon solar cells, in order to increase the collected photons and thus improve their efficiency. Alkaline texturing consists of the formation of square-based pyramids randomly distributed on the surface of the wafer. This chapter includes a detailed...

Luminescence emission based characterisation has undergo a great evolution since its first applications in photovoltaics, more than 15 years ago. Two-dimensional measurements gather interest from the very beginning, due to the opportunity of detecting process related defects without the need of a detailed quantification. Qualitative measurements re...

Deviations from ideality on the behavior of solar cells can be studied by the local ideality factor defined as the inverse of the slope of the I-V characteristic curves. In this work the local ideality factor is used to characterize damaged cells from the point of view of a two-diode model. By means of the two-diode model, only what takes place in...

The laser isolation of p-n junction is the origin of electrical damage in solar cells. Although several models explain this effect, it is usual to appeal to complex recombination mechanisms to get an accurate representation of their non-ideal I-V behavior. Other models give to an accurate and simple explanation of this damage introducing a connecti...

Laser processes in solar cells are the origin of a considerable mechanical and electrical damage. This paper introduces a model that presents a good fitting to the laser-induced damage, previously characterized as an extra recombination diode, with a highly variable ideality factor, connected to the rest of the structure through an interconnecting...

To maximize photovoltaic systems performance the monitoring of them is essential. There are several faults that produce energy losses in the system. When a fault happens the monitoring system has to detect it and give an indication about which is the component with the fault. For this, in most system a set of parameters are measured, usually four:...

The IBC structure is one of the champions in the efficiency competition of silicon devices. Industrial cells are produced with efficiency values surpassing 24%, what is due to an excellent design in terms of separation from the region where carriers are energized and emitters where these carriers are selectively separated. Their position in the bac...

In this work our target is to obtain low surface emitter concentration with Gaussian profiles due to that have a strongly effect on solar cell efficiency. Two kinds of phosphorus profiles were proceed experimentally, the first emitter profile is obtained with only pre-deposition process for various diffusion temperature and the second emitter profi...

Drilling process on wafers to produce EWT or MWT solar cells is a critical fabrication step, which affects on their mechanical stability. The amount of damage introduced during drilling process depends on the density of holes, their size and the chemical process applied afterwards. To quantify the relation between size of the holes and reduction of...

A solar cell sorting system developed between Isofotón S.A. and the Universidad del País Vasco is described. This system, which is of an industrial nature, aimed at enabling companies to carry out quality control work, is, at the same time a flexible and totally programmable system which makes it apt not only for the basic work required, but also a...

Mechanical stability of back contact solar cells deteriorates when holes (MWT, EWT) or grooves (TWT) are created in the wafer. These operations are essential for these structures so we found necessary to quantify the magnitude of this damage. A set of wafers with the EWT structure was produced and its mechanical strength measured by the Ring on Rin...