Monday, November 24, 2014

How do scientists from around the world collaborate? What do these collaborations look like?


Excellent question! Every collaboration is different. In our collaboration, we have bi-weekly meetings in which we bring up any issues that we are having. While we aren't all physically in a single location, we talk and present over the internet using conferencing software. At each meeting, a different sub-group presents. During these presentations, other group members will ask questions and offer suggestions for improving work and making heads or tails of confusing data. In our research group, too, we have weekly group meetings where we talk about what is going on in the lab and group members also present both on things that they are working on and things that might be interesting to the group (such as new or relevant research reports). For some collaborations, researchers will travel to physically meet with each other and discuss research. This is how many collaborations are born.

An important part of being a researcher is presenting work at conferences. At conferences, people come in often from all over the world to talk about their work and learn about what other researchers are doing.

Tuesday, November 18, 2014

I hear about silicon solar cells, but I have also heard mention of CdTe cells. I know that you work on CZTS and I've also heard mention of a crazy thing called CIGS. What does all this mean?

These different labels for cells refer to the material that makes up the absorber layer. CdTe, Si, Cu2ZnSn(S,Se)4 (CZTSSe), and Cu(In, Ga)Se2 (CIGS) are all materials that can be used in a specific layer of a solar cell (something used to convert energy from the sun into electricity) in which light is absorbed and the energy in that light converted into charge carriers (electrons and what are known as holes). There are a variety of solar technologies commercially available and a single technology may not immediately dominate. CdTe-based cells have been less expensive than other types recently, however there are scarcity concerns about this technology that will eventually limit the extent to which cost can be lowered. Si cells are pretty ubiquitous (and inexpensive), but are not quite as inexpensive as CdTe-based cells due to added processing requirements. CIGS cells are just recently coming to market. Technologies like CZTSSe have not been commercialized since they are still in the research stages (comparatively low, but rapidly improving efficiencies). A new technology on the block that may really shake things up are perovskite solar cells, which have had a meteoric rise in efficiency making them fairly comparable in terms of efficiency to CIGS and CdTe, but this technology has some major degradation issues (water, even the water vapor in air kills cells). Both CZTSSe and perovskite cells are earth-abundant and it is likely that they will be able to be made more inexpensively than competing technologies. Regardless, silicon-based cells will certainly remain in the overall mix. It is likely that, for a long time, solar cells based on several different materials systems will all compete, meanwhile enhancing our understanding of these systems.

Thursday, October 16, 2014

Why solar and not other sources?

Good question! The answer may be surprising. In some locations, solar will not be the best, although it will work well in many locations. For example, it probably would not be wise to install solar modules above the arctic circle because, although you would generate energy during the summer, it is very dark during the winter and you wouldn't get much energy. It is important that solar energy be able to compete with other energy sources. Although it often takes some time and money to bring a competing technology to catch up to existing technologies, business dictates that there be some reason for the change. The new technology must be able to stand on its own two feet once subsidies go away. In some places solar energy will be the best option and in other locations it will not. Solar will likely play a significant role in upcoming years in the power grid (in both developed and developing countries), but it will likely not play a role in all places.

In terms of impact, solar energy is capable of making a big difference in the individual lives of people with little access to other energy sources. In addition to contributions to the larger grid used by those who have many resources, these smaller contributions are also valuable. It is important to consider these small-scale but large-impact contributions when going about research. Without light, it is hard for small isolated farmers not connected to the electrical grid to connect with larger communities, learn, read, and thrive. It is much more difficult to sell goods without the internet. Access to the internet, which we often take for granted, broadens horizons.