QCM-D for deep scientific understanding on solar cells
Wednesday, April 20, 2011
“I always had a dream to do these measurements” Professor Michael Grätzel at EPFL in Lausanne says about investigating his dye-sensitized solar cells with the QCM-D technique.
“For us, using QCM-D is about deep scientific understanding. We will be able to study spatial resolution, get information about viscoelastic properties and closely study the oxides we work on. I suspect we will see other interesting effects too”, Professor Grätzel says, continuing:
“I’m so happy we finally have this machine to do preparations and study the kinetics of dye impregnation”.
Being able to do measurements on the nano-scale is highly important for many of the spin-off companies, which are a result of his research.
“The newest company uses nano-crystals in batteries. Working on the nano-scale is extremely important for this development of new materials” he says.
Professor Michael Grätzel at EPFL.
Professor Grätzel is active at the École Polytechnique Fédérale de Lausanne, EPFL, and he has an impressive resume. That has not always been the situation though.
“It was difficult to convince our peers in the beginning” he says and explains how being a scientist in his view can be both “tortuous” and a huge privilege at the same time:
“As a researcher you struggle a lot with funding on the one hand and in parallel with challenging scientific issues; are the compounds right, will the experiment work, will you get funding for what you want to do, and so on. But in the end it’s a fascinating profession we have” he says.
In 1991 Professor Grätzel and his colleagues reported their invention of the dye-sensitzed solar cell, DSSC, also known as the Graetzel cell. At the time he was already working at EPFL. The idea to use a dye molecule as the electron provider in the solar cell was borrowed from plant’s natural photosynthesis that employ chlorophyll molecules to harvest light and generate electric charges.
Photosynthesis inspired the group to use a dye as the electron provider.
The examples to illustrate Professor Grätzel’s impact in the scientific world since then are numerous: over 70 000 scientific quotations, more than 900 published articles and 50 patents speak for themselves, not to mention the many awards and prizes he has received. Still, Professor Grätzel remains humble about his achievements.
“I work in a terrific group of 50 scientists with many independent people around me. We are all driven by a mission oriented curiosity” he says.
The mission he refers to is the challenge of an upcoming energy crisis.
“We have a chance to contribute and make a change in the energy emergencies the world will face when we run out of oil. Renewable energy is going to be the only option left” he says.
Illustration of a dye sensitized solar cell, also known as Graetzel cell.
Some of his latest results in this quest come from collaborations with a group at Chalmers University of Technology in Gothenburg, where Professor Grätzel’s PhD student Hauke Harms recently paid a visit. There, Mr Harms had a chance to make measurements on preparations of his dye sensitized system in the very same group that once developed the QCM-D technique in the 1990’ies.
The specific measurements concerned the kinetics of how the dye adsorbs in the nano-crystalline and mesoporous titanium oxide structure that together with the dye constitutes the key element in a DSSC.
“In just two weeks we received stunning, very new results and we are all excited about this. It is truly a privilege to have these experts on our side” Professor Grätzel says, expecting the future measurements and results to bring more valuable information to his research.
