A 2D Finite Element Method (FEM) solves Ohm’s law in the two electrodes. The latter are coupled trough the 1D I-V characteristics of the reference small-area device. Laoss simulation with the electric module can be used to optimize the geometry of OLEDs and solar without costly and time-consuming processes of device fabrication and testing
Reduction of electrical losses
Optimization of the design of the electrodes in OLEDs and PVs. The potential distribution at the top electrode can be optimized by including a metal grid. Suitable for LED lighting panels and large area solar cells.
Metal finger width optimization
Metal fingers (metal grid) can be added to the transparent electrode of a PV cell in order to improve its conductivity, and as a consequence to improve the device efficiency. In this case the width of the metal finger has been optimized in order to find the best compromise between two counter-acting effects: shadowing due to the metal finger and low conductivity due to the absence of a metal finger.
Choice of the Electrode Material
Two important electrodes properties are its transparency and conductivity. Choosing the most efficient material is not an easy task since the relative impact of the conductivity and transparency change with the device size. In this case is shown how Laoss can be easily used to produce a chart of the best material choice for a PV cell depending on the device size.
Sample 1: Transparency = 85%, σ = 1.14x10^6 S/m
Sample 2: Transparency = 90%, σ = 6.67x10^5 S/m
Studying non-ideal Effects in OLEDs and Solar Cells
Electrical shunts are unwanted short-circuits between the two metal electrodes that are drastically degrading the efficiency of the device.
Laoss can simulate the distribution of potential and current in the device, when there are electrical shunts. In an OLED these results can be correlated, for example, to the non-uniformity of the device luminescence.
Understanding Electrical Cross-talk in a RGB OLED Pixel Array
Adjacent pixels in OLED displays can be electrically coupled through the lateral leakage current of a common layer. This effect, called cross-talk, results in unwanted light emission from an unaddressed pixel of different color and reduces the device contrast ratio and can be detrimental for the color gamut of the device.
With laoss we can achieve a quantitative understanding of electrical cross-talk in OLED displays.
Laoss simulations have been successfully tested on several experimental results. For example, different experimental results reported in the paper: K. Neyts et al.: “Inhomogeneous luminance in organic light emitting diodes related to electrode resistivity", have been reproduced.
Here we show the agreement between the experimental and simulated dependence of the luminance on the position along the electrode.