Veronica Bermudez of NEXCIS presented paper #C1.9 (“In-line quality control of chacolpyrite-based solar cells by advance Raman spectroscopy”). The work was driven by the fact that CIGS’ competitiveness is compromised by relatively low efficiencies achieved at the module level (9-13%). The presence of inhomogeneities that degrade the optoelectronic properties of the layers is the culprit. The researchers wanted to determine the presence of such inhomogeneities at an early stage in the fabrication process and Raman spectroscopy is well-suited for the application – specifically, use of quasi-resonant Raman scattering measurements. Bermudez said that Raman measurements at quasi-resonant conditions are a fast and sensitive tool for assessing alloy composition.
Yanyan Cao of DuPont presented paper #C2.2 (“Cu2ZnSn(S,Se)4 thin film solar cells from binary and ternary chalcogenide nanoparticles”). One reason researchers are interested in CZTS for solar PV applications is because it comprises earth-abundant elements/compounds – a definite cost consideration. Cost considerations also come into play by the choice of using nanoparticles; because they are dispersable in various solvents, they enable multiple low-cost coating techniques such as R2R processing on flexible substrates.
In the coming days, watch for podcast interviews with Daniel Josell of NIST and Fred Seymour of PrimeStar Solar.