Organometallic Ruthenium Complexes as Next-Generation Chromophores for Hybrid Solar-Cells – CORuS

The exploitation of renewable energy sources is nowadays promoted by the public awareness that the earth’s fossil fuel reserves shall run out during this century and that meanwhile the world energy consumption is continually increasing. Thus our society urgently needs for energy transition that would emanate from an energy mix based on various energy sources though mainly promoting renewable energies. In this context, solar energy appears as one of the key resources to fulfill the rising worldwide demand for clean and sustainable power sources. One attractive approach consists in the development of systems that mimic natural photosynthesis. Based on this concept, Dye-sensitized Solar Cells (DSCs) have attracted great interest due to their versatility, low-cost and easy manufacturing. DSCs are acknowledged as a highly promising technology and represent a viable alternative to traditional Si-based solar cells.
Since the light-harvesting properties of this device essentially rely on the photosensitizer, the present project focuses on the design and synthesis of innovative molecular dyes; it also includes the fabrication and characterization of photovoltaic devices.
The CORuS project stems from recent advances from the PI’s group: the development of original organometallic complexes including a Ruthenium-diacetylide motif as next-generation chromophores for DSCs. Organometallics, by including metal ions into conjugated structures, offer many advantages such as electron conductivity enhancement or photoresponse broadening, and represent first-class components for molecular electronics. Accordingly Ru-diacetylide dyes present remarkable optical properties and afforded excellent PV performance in DSCs, higher than fully organic or Pt-based analogous dyes. Thus, considering the amount of potential improvements attainable through molecular engineering, the new-generation organometallic dyes represent a promising and versatile approach to the preparation of highly photoactive materials and efficient PV devices.
Ru-diacetylide complexes represent the cornerstone of this proposal which global objectives are panchromatic visible-light absorption achievement and PV device performance improvement. The high modularity of such complexes will allow the preparation of a wide range of molecular structures applicable to different PV technologies, the principal one being DSCs, but also inverted p-type DSCs and bulk-heterojunction solar cells. It will also represent a stepping-stone towards investigation of alternative metal fragments. In view of the good preliminary results reported by the applicants, the molecular engineering of new chromophores described in this proposal is expected to afford state-of-the-art power conversion efficiencies in standard DSCs. To this end, the project encompasses a challenging combination of diverse skills such as organic/organometallic synthesis, theoretical chemistry, photo- and electrochemistry, material chemistry, device processing and physics. The whole project will bring from the molecule to the device; hence, beyond the molecular synthesis aspect, thorough work of optoelectronic and PV characterization will be performed.
The CORuS project will take place within a highly competitive international scientific context, but since the future of hybrid and molecular photovoltaics is driven by the design of cutting-edge photoactive compounds, the innovative concept of organometallic complexes described in this proposal could make a significant breakthrough.
After all, to promote the use of photovoltaics and widen their application towards more effective exploitation of the solar energy, efforts should be made to increase the versatility and diversity of the device. Thereby, within the near future, the various PV technologies will take their place in the solar energy mix and will all play a role in the global prominence of this form of renewable energy, leading to highly positive environmental and societal impact.