Semiconductors play a crucial role in modern technology across various fields. The term “semiconductor” was introduced in the XVIII century, marking the beginning of a journey filled with discoveries and technological advancements. This article offers a comprehensive review of the historical landmarks in semiconductor development and explores the associated phenomena concerning different types of photodetectors. It also examines the key performance metrics of commonly used semiconductor materials, considering the structural variations. Additionally, the article highlights various applications of semiconductors, illustrating their significance in everyday life. By doing so, it aims to engage new readers while providing a foundational understanding for those interested in delving into this field.

Solar cell equivalent circuit modelling is usually based on continuous I-V models, with a set of data obtained by analytical expressions. This work proposes an almost discrete novel mathematical method and correspondent electrical model, based on the I-V curve adjustment at every two adjacent points. It is based on the discretisation of any diode model behaviour, such as the 1M5P (also known as 1D5P) or the 1M7P (also known as 2D7P). For this reason, the model is named d1MxP, meaning that it is a discrete (d) model (1M) with x parameters (xP). The modelling methodology validation process uses experimental data already published in the literature. According to the presented results, the proposed method shows increased accuracy when compared to the 1M5P or 1M7P equivalent models. The accuracy on the maximum power point and fill factor determination is relevant, resulting in an improvement of up to 3.34% in the maximum power, up to 5.70% in its voltage and up to 8.20% in its current, for the analysed data. Furthermore, Fill Factor values, have variation from up to 35.98%. The temperature influence on the silicon solar cell is also analysed, to validate the results. The proposed method allows highly accurate curve fitting to the (experimental) points and consequently, to obtain a more accurate model to analyse the performance of solar cells under different conditions.

This research work aims to study photovoltaic systems that generate energy for self-consumption using different traditional technologies, such as silicon, and emerging technologies, like nanowires and quantum. The photovoltaic system without batteries was implemented in a residential property in three different places, in Portugal. According to Portuguese Law, the sale of surplus energy to the grid is possible but the respective value for its selling is not defined. To evaluate the project viability, two different analyses are considered: with and without the sale of surplus energy to the grid. Results show that if there is no sale of excess energy produced to the grid, the project is not economically viable considering the four different technologies. Otherwise, using traditional technologies, the project is economically viable, presenting a payback time lower than 10 years. This shows that the introduction of nanostructures in solar cells is not yet a good solution in the application of solar systems namely with the current law. Furthermore, independently of the used technology, the current Portuguese law seems to difficult the investment return, which should not be the way to encourage the use of renewable sources.

The performance of photovoltaic solar cells is usually analyzed using continuous models, for instance, 1M5P. I-V and P-V curves are fitted by a mathematical expression from the electrical model. In the case of 1M5P, characteristics are fitted using five parameters that are obtained using a small number of I-V points from a wider set of data, keeping the curve shape given by the mathematical expression from the model. A novel model was recently proposed to overcome this issue. The d1MxP model is based on the discretization of the electrical behavior of the diodes in models such as 1M5P. The d1MxP methodology is equivalent to an analytical incremental calculation and since it connects the given points, the model error should be lower than the one obtained using models as 1M5P. It is based on the connection of adjacent points (with small voltage differences) instead of having the entire voltage range represented by some parameters (as the continuous models do, for instance, 1M5P). In this work, the d1MxP model is applied to perovskite solar cells and paint-type dye-sensitized solar cells. The aim is to analyze the behavior of the discrete model in different third-generation solar cells since their performance cannot be well characterized by the 1M5P model. The accuracy on the maximum power point is relevant, resulting in perovskite solar cells, an improvement of up to 2.61% and, in paint-type dye-sensitized solar cells, an increase of up to 5.03%.

Renewable energy sources are becoming more and more essential to energy production as societies evolve toward a fossil-fuel-free world. Solar energy is one of the most abundant sources of green energy. Nanoantennas can be used to improve and enhance the absorption of light into a photovoltaic cell in order to generate more current. In this study, different nanoantenna structures are analysed in tandem with a silicon solar cell in an effort to improve its output. The nanoantennas studied are metallic aperture nanoantennas made up of either silver, aluminium, gold or copper. The three geometries compared are rectangular, circular and triangular. The maximum field enhancement obtained is for an aluminium rectangular nanoantenna of 50 nm thickness. Despite this, the geometry with more improvements compared with a basic silicon cell was the circle geometry with a 100 nm radius.