Photovoltaic CIGS Solar Cells
This project focuses on the fabrication of solar cells based on copper, indium, gallium, and selenium (CIGS). This material system is just starting to be commercialized. A typical structure for a CIGS solar cell and a band diagram are shown below.
CIGS solar cells with efficiencies above 20 % have been demonstrated over the past few years. In our group, we focus on the stacked elemental layer approach as the most promising approach for realizing low cost, mass produced, solar cells. At the University of Maryland, we have established an international collaboration with Kyoungwon University in Korea. This group has demonstrated high crystalline CIGS films with grain size of order 1-2 m. These were obtained in two steps. First, a sequence of Cu/In/Ga layers were deposited (by e-beam or sputtered) and then this film was selenized in a rapid thermal processor. The high quality crystals are shown in the next figure.
The optimization of all the steps for fabricating CIGS solar cells is in progress in our laboratory. Future work will study the growth of CIGS solar cells on flexible substrate and will investigate the possibility of creating an ink of CIGS nanocrystals.