With this new technology from the U of T Engineering, printing solar cells will be possible and cheap. Dr. Hairen Tan and his team developed the perovskite solar cell that is low in cost, printable, and can turn any space into a power generator. Regarding this innovation, Professor Ted Sargent, the Canada Research Chair in Nanotechnology, said:
“Economies of scale have greatly reduced the cost of silicon manufacturing. Perovskite solar cells can enable us to use techniques already established in the printing industry to produce solar cells at very low cost. Potentially, perovskites and silicon cells can be married to improve efficiency further, but only with advances in low-temperature processes.”
Today’s solar cells contain either crystalline silicon or thin film. Monocrystalline and polycrystalline solar cells are produced in very high temperatures and solved in hazardous chemicals. This is all due to their necessity to be highly pure in crystalline silicon.
Meanwhile, perovskite solar cells consist of tiny crystals that are low in cost and light sensitive. Also, these crystals that make the raw material of perovskite can be in liquid form. Thus, the cells can be printed on glass or plastic with the ‘solar ink’.
Although the production seems simple, there is a key point to producing an efficient solar cell. In order for the solar cell to generate electricity, certain electrons must use photons from the Sun to be excited and follow the electric circuit. This layer where the electrons are excited is the Electron Selective Layer, ESL. According to Tan, the production of a good ESL has been the challenge in the production perovskite cells:
“The most effective materials for making ESLs start as a powder and have to be baked at high temperatures, above 500 degrees Celsius. You can’t put that on top of a sheet of flexible plastic or on a fully fabricated silicon cell — it will just melt.”
To resolve the issue, Tan and his team created a new chemical reaction that will make a good ESL out of nanoparticles. As a result, the heat needed for the reaction has been lowered to 150 degrees Celsius.
The perovskite solar cell has a 20.1% efficiency while the highest efficiency for a crystalline solar cell is 26.3%. Another thing about this new solar cell is that it can keep its efficiency capacity at 90% for 500 hours.
Colleagues all around the world also recognize the importance of the new layer. Professor Alan Aspuru-Guzik from the Department of Chemistry and Chemical Biology at Harvard University said:
“The Toronto team’s computational studies beautifully explain the role of the newly developed electron-selective layer. The work illustrates the rapidly-advancing contribution that computational materials science is making towards rational, next-generation energy devices.”
Additionally, Professor Luping Yu from the University of Chicago’s Department of Chemistry stated:
“To augment the best silicon solar cells, next-generation thin-film technologies need to be process-compatible with a finished cell. This entails modest processing temperatures such as those in the Toronto group’s advance reported in Science.”
The perovskite solar cell is not an innovation that only interests the energy industry. If taken to a commercial level, these cells can integrate free energy production to the smartphone covers, windows, and such.