Organic semiconductors (OSCs) with their unique mechanical properties provide immense opportunities to maximize their performance through an adequate molecular design. This field has suffer huge progresses over the last few years, with devices such as OLEDs already in the market and the realization of efficient prototypes of organic photovoltaic cells or field-effect transistors. However, to take fully advantage of the opportunities offered by organic semiconductors to build cheap, light-weight, flexible devices, smart semiconductors able to respond to a variety of physical stimuli including temperature, pressure, humidity, light, as well as biomarkers and chemical traces are still needed.

In this area we are working on two different type of materials:

1. Small-molecule self-assembling semiconductors: The electrical and optical properties of molecular semiconducting materials   are dictated by the whole collective rather than by individual molecules. In this context in the last few years we have made important contributions in the development of high-mobility self-assembling n-, p-type and ambipolar discotic organic semiconductors for their incorporation in devices following an adequate design both at a molecular and a supramolecular level (Chem. – A Eur. J. 2018, 24, 3576–3583;  J. Mater. Chem. C 2017, 6, 50–56; ACS Appl. Mater. Interfaces 2016, 8, 26964–26971). More recently we have obtained self-assembling semiconducting materials with thermo- and piezochromic properties by inducing changes on the supramolecular structure of the constituting units (ACS Appl. Mater. Interfaces 2020, 12, 10929–10937). Because non-covalent interactions are weak and flexible, their making and breaking have a great potential to achieve reversible transformations and hence external-stimuli-responsive and switchable molecular functional materials. The mechanism behind this transformation has been elucidated which allows us to give clear guidelines to design new molecular candidates with improved performance (J. Am. Chem. Soc. 2020, 142, 17147–17155).
2. Semiconducting pi-conjugated polymers: Although charge transport properties of semiconducting polymers are usually notably lower than those of their small-molecule counterparts, polymers offer important advantages in terms of stability and processability.  In this context we pursue robust polymeric semiconducting materials, to be implemented in solar cells and be used among other applications as photocatalysts to generate non-contaminant fuels such as hydrogen from water splitting (ACS Appl. Energy Mater. 2020, 3, 4411–4420) and induce chemical transformations (Polym. Chem. 2018, 9, 4585–4595) driven by sunlight.

On the other hand, by taking advantage of the porosity and photoactivity that characterize porous polymers we have successfully applied these materials to efficiently detect and remove harmful pollutants via adsorption-photocatalysis synergies. Particularly we have recently developed novel microporous pi-conjugated polymers which are able to detect nitroaromatic explosives, which is one of the most critical issues concerning national security and environmental safety (Chem. Mater. 2019, 31, 6971–6978).  The selectivity and sensitivity of the process can be efficiently tuned by controlling the energy levels of the frontier orbitals of the sensing polymers. Theoretical calculations provide insights in the mechanism behind the different sensing performance and allow us to establish clear structure-property relationships (J. Mater.Chem. C 2020,  8, 15416–15425).