The bottom line, observes Buonassisi, is that the very feature that makes the PERC technology efficient — the special architecture designed to capture solar energy efficiently — is what reveals a problem inherent in the fabricated material. “The cell people did everything right,” he says. “It’s the quintessential law of unintended consequences.” And if the problem is the higher density of excited electrons interacting with defects in the silicon wafer, then developing effective strategies for dealing with it will only get more important because next-generation device designs and decreasing wafer thicknesses will bring even higher electron densities.
To Buonassisi, this work demonstrates the importance of talking across boundaries. He advocates communication among all participants in the solar community — both private companies and research organizations — as well as collaboration among experts in every area — from feedstock materials to wafers, cells, and modules to system integration and module installation. “Our laboratory is taking active steps to bring together a community of stakeholders and create a vertically integrated R&D platform that I hope will enable us to more quickly address the technical challenges and help lead to 10 TW of PV by 2030,” he says.
This research was funded by the National Science Foundation, the U.S. Department of Energy, and the National Research Foundation Singapore through the Singapore-MIT Alliance for Research and Technology.
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