The Silicon and New Concepts for Solar Cells (SyNC) group at the Instituto de Energía Solar (IES), Universidad Politécnica de Madrid (UPM) leads the project COMIC — “Combining organic molecules and two-dimensional materials for solar cells” (PID2022-142425OA-I00), with Simon Svatek as Principal Investigator. The project was funded under the “Proyectos de Generación de Conocimiento 2022” call by MCIN/AEI/10.13039/501100011033, with a total awarded amount of 125,000 € and a 3-year duration.
IES and the SyNC group
IES research spans the full photovoltaic value chain: from materials science for next-generation solar cells to device engineering and the design and operation of solar power plants. The institute’s multidisciplinary environment brings together researchers from physics, materials science, engineering, and chemistry, and also explores PV applications in vehicles and energy storage as well as broader societal challenges related to large-scale solar deployment.
SyNC contributes to this mission by exploring new device concepts and materials platforms—including ultrathin absorbers—to expand where and how solar energy can be harvested.
Why COMIC? Solar energy in “new places”
Conventional silicon photovoltaics dominate the market, but silicon cells are often heavy, rigid, and brittle, which limits their use in many emerging applications. Meanwhile, there is growing interest in PV that can be integrated into textiles, windows, vehicles, built environments, agri-PV systems, or even floating platforms—settings where lightweight, thin, and optionally semi-transparent solar cells are highly attractive.
COMIC starts from the idea that harvesting solar energy “everywhere” will require PV technologies that are not only efficient, but also adaptable in form factor and compatible with low-temperature processing.
Why 2D materials + organic molecules?
Two-dimensional (2D) materials, especially transition-metal dichalcogenides (TMDs), can absorb light very strongly despite being extremely thin. This creates the possibility of solar cells with active layers that are tens of nanometres thick, potentially enabling flexible or semi-transparent devices. At the same time, organic molecules offer well-defined energy levels, which makes them promising candidates for designing energy-selective interfaces—a key ingredient for more advanced solar-cell concepts.
COMIC combines these two material classes to pursue two complementary research directions.
Objectives of COMIC
O1 — Ultrathin, high-performance TMD solar cells
A long-standing bottleneck in ultrathin 2D-material solar cells has been achieving high photovoltage together with efficient carrier extraction. Our group previously reported a layered-materials solar cell with an open-circuit voltage of about 1.02 V, demonstrating that high photovoltage is possible in this materials family.
COMIC builds on this by targeting device engineering challenges, especially contact formation. A central goal is to develop ohmic (low-loss) contacts to TMD absorbers using approaches that avoid damaging interfaces, enabling devices that combine:
- high photovoltage,
- improved photocurrent extraction,
- and reduced resistive/contact losses.
A second, closely related aim is to demonstrate semi-transparent ultrathin devices, where part of the sunlight is converted to electricity while the remaining transmitted light can be used (for example) in window-integrated PV concepts.
O2 — A hot-carrier concept using graphene + molecular energy-selective contacts
To exceed conventional efficiency limits, solar-cell concepts must reduce fundamental energy-loss pathways—especially carrier thermalisation. COMIC explores a hot-carrier device concept using:
- graphene as an absorber (where hot carriers can persist longer than in many bulk semiconductors), and
- molecular contacts as energy-selective filters for carrier extraction.
This is a high-risk/high-gain research line aimed at establishing experimental pathways toward devices that operate on principles different from conventional single-junction solar cells.
Selected publications
- High Conductivity and Thermoelectric Power Factor in p-Type MoS₂ Nanosheets
https://pubs.acs.org/doi/full/10.1021/acsaem.4c02932
