Currently, organic materials used in these devices offer greater versatility and efficiency at a lower cost than the available inorganic ones, but they show stability problems when in contact with an aqueous medium. The study published in The Journal of Physical Chemistry claims to achieve an exceptional stability in these devices and represents an important step in obtaining solar fuels from organic materials.
Sixto Giménez, coordinator of the research, noted that through the device developed "the production of hydrogen has been achieved for three hours, demonstrating a stability of organic materials that had not been reached so far." Organic photovoltaic devices corrode in water and damage easily. "Our strategy has been to place a physical barrier between the photovoltaic part and the catalyst that makes the hydrogen generation reaction. In order to achieve this we have deposited compact layers with nanometric titanium oxide material that not only acts as a barrier between the water and the photovoltaic part, but also connects electrically the photovoltaic part and the platinum catalyst. Using this strategy we can greatly increase stability while maintaining the performance of these devices," explained the researcher Antonio Guerrero.
Obtaining solar fuels like hydrogen from water and sunlight is a strategy aimed to solve the global energy problem. "We can have totally renewable resources like sunlight and water for obtaining an energetic conductor such as hydrogen. In addition, hydrogen is a chemical compound with endless applications in industry such as the generation of fertilizers or the synthesis of hydrogen compounds," noted Giménez.
The research has been developed under the PHOCS (Photogenerated Hydrogen by Organic Catalytic Systems) project, funded under the 7th Framework Programme of the European Union, which aims to project aims to develop new devices based on organic semiconductor materials to perform the photodecomposition of water leading to the efficient generation of hydrogen. It seeks to optimize the use of cheaper and sustainable materials for the production of hydrogen.