angelfelipe

 

Felipe A. Angel
Phone: (562) 2354 9547
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PhD in Chemistry
University of Rochester (USA), 2015

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The work of our research group is framed in the multidisciplinary area of Material Science, field that combines the scientific disciplines of Chemistry and Physics with Engineering. Within this area, we focus on Organic Electronics, which studies the chemical synthesis, as well as the fabrication and characterization of optoelectronic devices. Particularly, we study organic and hybrid organic-inorganic perovskite semiconducting materials for their application in the generation of electricity as well as emission of light.

Organic photovoltaic (OPV) devices: Photovoltaic (PV) devices have been widely studied and developed, but it is only in the last decade that organic photovoltaic (OPV) devices have reached high efficiencies, making them competitive with the current technologies in the market. OPV devices have many advantages compared to its traditional PV counterpart, such as lower cost due to the use of ultra-thin layers, feasibility of industrial processes of fabrication, and lower environmental impact of the active materials. In addition, OPV devices can be fabricated on flexible substrates, making them more suitable for integration with other applications from roofing materials to portable chargers. Nevertheless, the current efficiency performance must be improved further for OPV devices to be competitive with traditional PV devices and to approach the theoretical limit. In addition, the operational stability of OPV devices needs to be significantly improved in order to achieve a lifetime that is suitable for practical applications. Our group studies small molecules with optimum electrical, optical, and morphological properties to be utilize as semiconductors in OPV devices. Moreover, they must exhibit high stability through the incorporation of functional groups compatible with the device operating conditions.

 

Foto 1 fangelFigure 1. OPV prototype panel (Konarka).

Perovskite photovoltaic (PPV) devices: A novel photovoltaic technology that has received much attention in the last few years is the perovskite photovoltaic device (PPV), which surpasses both OPV and the dye-sensitized solar cells in efficiency. Ammonium trihalogen plumbates (CH3NH3PbX3) perovskites have shown excellent properties as absorbing and charge transporting materials. One of the most promising aspects of these materials is that simple devices can be completed, using the same organic materials used in OPV devices as buffer layers for carrier collection. Although perovskites can be sublimed, there are limited numbers of reports on thermally evaporated devices. Our group studies the device fabrication of PPV by this technique, facilitating its fabrication and reproducibility. There is a lack of reports on device lifetime, being an unexplored area that needs to be developed. In order to consider PPV devices as a real option for power generation, sufficient device lifetime must be demonstrated which would entail considerable materials and device research.

Organic light-emitting diode (OLED): the use of organic light-emitting diodes (OLED) has expanded in the display industry to the point of replacing liquid crystal (LCD) in several applications, such as mobile phones, smart watches, and virtual reality headsets, and even, in the lighting sector. It is projected that the OLED market will reach USD 50 billion in the next decade. Despite of the major progress experienced by the OLED technology, there are still scientific and technical aspects limiting a wider spread and reduction of the production costs, such as, device stability and efficiency. One approach to the latter is the application of high current densities, which generates higher light outputs, sacrificing, however, the device stability even further. One solution to obtain high light outputs applying lower current densities is by using tandem structures, this is, two or more subcells connected in series through an interconnecting (IC) layer. Ideally, an IC layer must be capable to generate and inject the corresponding charge carriers to the subcells with zero additional voltage, in addition to be optically transparent. Our group studies different materials that can be used in the IC layer. In addition, we explore novel materials with high stability, especially those capable to emit in the blue region, as it still faces degradation issues compared to green and red emitting materials.

Foto 2 fangelFigure 2. Green OLED pixel emission.