Nanometric sensors detect polluting gases in the atmosphere

Scientists at Unesp and MIT synthesize and test nanostructured oxide semiconductors for use in gas sensors for environmental control and monitoring.

The discovery of two semiconductor materials structured on a nanometric scale (one billionth of a meter) – copper oxide and tin oxide – with high sensitivity and selectivity in detecting polluting gases in the atmosphere, may be used to develop sensors for environmental control and monitoring. The announcement was made today, October 22, during the second symposium of FAPESP Week 2012, held at the Massachusetts Institute of Technology (MIT) in Boston.

The outcome is fruit of the project “Advances in nanostructured oxide semiconductors for gas sensors,” conducted by research teams led by Professors José Arana Varela of the Chemistry Institute at the São Paulo State University (Unesp) in Araraquara, and Chief Executive Officer of the FAPESP Executive Board, and Harry Tuller of the Department of Materials Science and Engineering of MIT. 

“In addition to the nanometric scale, which offers semiconductors greater sensitivity, other factors are also important in defining these materials,” says Professor Varela. “Some of the tests performed at MIT show that different ways of structuring semiconductor particles can lead to significant changes in electrical conductivity and thus modify the response of the materials when they come into contact with gases. That’s why our next step will be to explain why the morphology is so relevant to this process.”

Cooperation between the two research groups has been complemented by the expertise and laboratory infrastructure each team provides. According to Varela, the team established at Unesp upon creation of the Multidisciplinary Center for Development of Ceramic Materials (CMDMC) – one of FAPESP’s Research, Innovation and Dissemination Centers (RIDC) – in Araraquara in 2001, has a large capacity for synthesizing materials and preparing samples. At MIT, Harry Tuller’s team has extensive experience with nanosensors, the ability to characterize the materials, and a very well-controlled system for analyzing eight samples at a time.      

“Synergy is the key word that describes our collaboration,” says Professor Tuller. “Personal interactions and the capacity for mutual transfer of specific expertise between the two groups, allowing, in just a short period of time, real advances to be made with regard to the type of materials developed and interpretation of the phenomena, has opened up new avenues of research.”

Since early 2011, this integration between teams from the two countries has been productive. One article has already been published in the high impact journal Advanced Functional Materials and others are in the final stages of preparation and editing.  

FAPESP Week 2012

FAPESP Week 2012, which began in Toronto October 17, continues this week with two more symposiums. On Tuesday, October 23, events are scheduled for the Brazil Institute of the Woodrow Wilson International Center for Scholars in Washington, DC and on Thursday, October 24, they will be held at West Virginia University in Morgantown, WV, both in the United States. 

The program includes the exhibition entitled “Brazilian Nature: Mystery and Destiny” a display on Brazilian biodiversity, opened today at the MIT Museum. It will also be displayed at the University of West Virginia.

Within the context of activities commemorating the 50th anniversary of FAPESP, FAPESP Week 2012 constitutes the second round of international gatherings designed to foster closer links between researchers conducting projects in their fields of work, discuss research underway, and develop new cooperative research projects. The first took place in Washington, DC October 24-26, 2011.   

Schedules and additional information about the events are available at