2014 Graduate Fellows / Graduate Fellows

Spencer Williams

Graduate Student, Materials Science & Engineering

Structural Investigation of the Organic/Inorganic Interface in CH3NH3PbI3-xClx Perovskite Hybrid Photovoltaic Devices

Addressing the world’s energy crisis through photovoltaics requires the development of technologies that are both efficient and cost effective to fabricate. Polymers are very cheap to process, but their efficiencies are low, and inorganic solar cells like CIGS and silicon are efficient but prohibitively expensive for large scale implementation. Organo-lead halide perovskites are a new class of photovoltaic material that can be processed under conditions similar to those for polymers, but they have efficiencies similar to inorganic materials. This material may allow us to use solar energy on a much wider scale, but growing high quality crystalline thin films of these perovskites is a significant challenge. Through my work we are developing the ability to use the transmission electron microscope (TEM) to visualize these crystalline thin films at the atomic level. This kind of microscope can characterize lattice structure, crystal orientation, grain structure, defects, elemental distribution, and most atomic scale structural phenomena. Using this level of analysis we are able to more fully understand the nature of the thin films we fabricate which has created the insight necessary to both understand and control crystal growth.

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– Mildred Dresselhaus, Professor of Physics and Electrical Engineering, Emerita and Institute Professor, Massachusetts Institute of Technology
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– Ronald Litzinger, President, Edison Energy
Since its founding the Clean Energy Institute has contributed more than $1.1 million toward the education of 66 STEM scholars and recruitment of 12 students through our fellowship programs.