Celdas Solares de Perovskitas: Una breve Introducción y algunas Consideraciones

The spectacular and unprecedented rise of so-called perovskite solar cells (PSCs) in conversion efficiency with low-cost manufacturing processes has grabbed the attention of the scientific community in the field of photovoltaics during the last four years. The inclusion of perovskite type absorber materials, typically CH 3 NH 3 PbI 3 , has been the key factor for the development of this emerging technology that has created great of expectations. However, many poorly understood aspects of its operating modes still need convincing explanations. This paper provides a brief introduction to the structure, materials and characteristics of PSCs. In addition, some remarks about the stability of these devices are provided and the state-of-the-art of several subjects of interest is discussed, such as the hysteresis phenomenon of current-voltage curves.El espectacular y sin precedentes ascenso de las llamadas celdas solares de perovskitas (PSCs, por sus siglas en inglés) en cuanto a eficiencia de conversión con procesos de fabricación de bajo presupuesto ha acaparado la atención de la comunidad científica en el campo de la fotovoltaica en los últimos cuatro años. La inclusión de materiales absorbedores tipo perovskita, típicamente el CH3NH3PbI3, ha sido el factor clave para el desarrollo de esta tecnología emergente con la que se tienen muchas perspectivas. Sin embargo, no son pocos los aspectos de su funcionamiento que aún faltan por comprender. En este trabajo se brinda una breve introducción a la estructura, materiales y características de las PSCs. Además se comenta especialmente acerca de la estabilidad de estos dispositivos y se discuten varios temas de interés como el fenómeno de la histéresis de las curvas corriente-voltaje

On fundamental mechanisms in dye sensitized solar cells through the behaviour of different mesoporous titanium dioxide films

Understanding mechanisms in DSSCs is fundamental for their improvement; this includes the nanocrystalline semiconducting layer behaviour. Different mesoporous TiO2 layers are fabricated and analyzed for possible use in DSSC solar cells. The preparations included the addition of P123 triblock copolymer as structuring agent to the synthesized anatase sol. This preparation was also mixed with Degussa P25 nanoparticles in one case and polystyrene latex in another. Mesoporous mixed TiO2-SiO2 thin layers were also analyzed. The diverse morphology and features are studied by microscopic techniques and by means of spectral quantum efficiency of a photoelectrochemical cell (PEC) that uses as photoelectrode the unsensitized porous TiO\_2 layer. Contact angle measurements are also performed. We have found that a very high specific area due to very small nanocrystals and small pores can hinder electrolyte penetration in the pores formed by TiO\_2 nanograins, affecting photoelectrodes efficiency