Research
Organic photovoltaics (OPVs)
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 their traditional PV counterpart, such as lower cost due to the use of ultra-thin layers, the 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 to achieve a lifetime suitable for practical applications. Our group studies small molecules with optimum electrical, optical, and morphological properties to be utilized as semiconductors in OPV devices. Moreover, they must exhibit high stability through the incorporation of functional groups compatible with the device's operating conditions.
OPV prototype panels (Konarka)
Halide Perovskite photovoltaics (HaP PVs)
A novel photovoltaic technology that has received much attention in the last few years is the halide perovskite photovoltaics (HaP PVs), which surpasses both OPV and dye-sensitized solar cells in terms of 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 HaP PVs by this technique, facilitating its fabrication and reproducibility. There is a lack of reports on device lifetime, an unexplored area that needs to be developed. In order to consider HaP PV 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 diodes (OLEDs)
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, smartwatches, and virtual reality headsets, and even in the lighting sector. The OLED market is projected to reach USD 50 billion in the next decade. Despite the major progress experienced by 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 the device stability even further. Using tandem structures is one way to obtain high light outputs by applying lower current densities. This is two or more subcells connected in series through an interconnecting (IC) layer. Ideally, an IC layer must be capable of generating and injecting the corresponding charge carriers to the subcells with zero additional voltage, in addition to being 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 of emitting in the blue region, as it still faces degradation issues compared to green and red emitting materials.
