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Accurate forecasting of yearly energy yield of photovoltaic devices under realistic operating conditions is key for numerous practical applications related to further evolution of photovoltaics. In this work we present development and validation of an energy yield model applied to planar perovskite solar cells. The model is based on the combination of advanced optical modelling and extensive opto-electrical characterization and takes the geographical location and the orientation of the device into account. Using the model, we first perform a detailed sensitivity analysis and indicate the key parameters and their interdependencies that most significantly affect the calculated energy yield values. We show that the results are dominated (within 4% of the final value) by the solar irradiance dependency of the short-circuit current density, and further by the temperature dependency of the open-circuit voltage and the fill factor, whereas the irradiance dependency of the open-circuit voltage and the fill factor are mutually compensated. In the second part of the paper, we investigate how the energy yield of the device is affected by the application of external light management foils. Different texture morphologies, geographical locations, and device orientations are included in the investigation. The results show that even under realistic operating conditions, the overall trends of the light management efficiency of textured foils are not that different from those observed under standard test conditions; the highest energy yield gains in the order of 7–11% are obtained by the tetrahedral texture which is indicated as optimal in all studied cases.

Optical modelling and simulations present an indispensable tool in the design, analysis and optimisation of thin-film solar cells of different technologies. In this paper highlights and challenges of different numerical modelling approaches are reviewed, from one-dimensional to rigorous two- or three-dimensional optical modelling. A concept of Coupled Modelling Approach (CMA) is proposed to be used, in which different optical models are coupled together to achieve best performance in speed and accuracy of simulations. A Combined Ray-Optics Wave-optics Model (CROWM) is presented as a simple example of the CMA. In the second part two examples of modelling and simulations are presented. To demonstrate the applicability of 3-D rigorous optical modelling, results of optimisation of periodic substrate surface texture in a micromorph silicon solar cell are shown. Furthermore, a model of non-conformal layer growth is employed to determine morphologies of internal interfaces and to make a selection of suitable textures for defect-less thin-film silicon layer growth. The CROWM simulator was employed to demonstrate the usability of coupled modelling on the example of optimisation of macro-textures in organic solar cells.

The rear side of a silicon solar cell is often designed to minimize surface recombination, series resistance, and cost, but not necessarily parasitic absorption. We present a comprehensive study of parasitic absorption in the metal layer of solar cells with dielectric/metal rear reflectors. The sub-bandgap reflectance of a solar cell or test structure is proposed as an experimentally accessible probe of parasitic absorption, and it is correlated with short-circuit current density. The influence of surface texture, dielectric refractive index and thickness, and metal refractive index on sub-bandgap reflectance-and thus current is then both calculated and measured. From the results, we formulate design rules that promote optimum infrared response in a wide variety of silicon solar cells. (C) 2013 Elsevier B.V. All rights reserved.