Low-Cost, Third Generation Solar Cells on Solid Ground

Novel, liquid-less design promises to improve long-term stability and durability of dye-sensitized solar cells while hitting high efficiency marks.

Distorted three-dimensional perovskite structure of cesium tin iodide (CsSnI3) at room temperature... — Image courtesy of Mercouri Kanatzidis/Northwestern University

The Science

The replacement of the corrosive, volatile liquid electrolyte in traditional dye-sensitized solar cells (DSSCs) with a novel semiconducting inorganic solid demonstrates that all-solid-state DSSCs need not sacrifice overall efficiency.

The Impact

Use of this new solid material sidesteps the long-term performance and durability issues of dye-sensitized solar cells and provides an opportunity for creation of cheaper, more efficient solar cells.

Summary

Current solar cell technologies are largely constrained by high production costs, low operating efficiency, and limited durability. A low-cost alternative to current silicon-based solar cell devices are thin film solar cells, such as dye-sensitized solar cells (DSSCs). DSSCs are made up of inexpensive, environmentally-benign titanium dioxide nanoparticles coated with light-absorbing dye molecules, and a liquid electrolyte. Research by the Argonne Northwestern Solar Energy Research (ANSER) EFRC at Argonne National Laboratory and Northwestern University has solved long-standing corrosion and durability problems associated with the liquid electrolyte. The corrosive, volatile liquid was replaced with a novel semiconducting inorganic solid, resulting in a solar cell that has competitive conversion efficiencies (10%) while withstanding high temperatures, high levels of humidity, and accelerated aging tests. The solid semiconductor consisting of cesium tin iodide (CsSnI₃) can be processed in solution, an appealing characteristic for keeping manufacturing costs low. The semiconductor also enhances light absorption of the DSSC in the red region of the solar spectrum, thereby outperforming conventional DSSCs. This discovery could lead to new solar cells that are both longer-lasting and highly efficient, while costing less to manufacture. A patent has been filed for this development.

Contact

Mercouri G. Kanatzidis
Northwestern University
m-kanatzidis@northwestern.edu

Robert P. H. Chang
Northwestern University
r-chang@northwestern.edu

Michael R. Wasielewski
Director of the ANSER Center EFRC, Northwestern University
m-wasielewski@northwestern.edu

Dick Co
Director of Operations and Outreach, ANSER, Northwestern University
co@northwestern.edu

Funding

DOE Office of Science, Basic Energy Sciences, Energy Frontier Research Centers (EFRC) program (development and fabrication of the semiconductor material); NSF Division of Materials Research (for design and fabrication of DSSCs); and Northwestern University’s Initiative for Sustainability and Energy (I.C.)

Publications

Chung, I., Lee, B., He, J., Chang, R.P.H., Kanatzidis, M. All-solid-state dye-sensitized solar cells with high efficiency. Nature. 485, 486-489 (2012) [DOI: 10.1038/nature11067]