Toward High Performance Epitaxial and Low-temperature Cu ( In , Ga ) Se 2 Solar Cells
The CIGS research effort at the University of Illinois represents a three-pronged approach to understanding and solving some of the most critical issues in CIGS device. These three prongs are: (1) development of a basic understanding of the issues limiting performance in CIGS devices, (2) advancing the performance of the devices through single crystal epitaxial layers for integration into high-performance cells, and (3) developing novel growth processes that will allow lower deposition temperatures necessary to multijunction devices. This paper presents an approach for CIGS/GaAs and CIGS/Ge heterojunction solar cells for multijunction high-efficiency devices. In addition, application of ionized physical vapor deposition to lowtemperature deposition of CIGS is described. The two projects will be coupled and results from one used to enhance progress in the other as part of the Beyond the Horizon and High Performance PV programs now starting.
Single crystal and polycrystalline CuInSe/sub 2/ by the hybrid sputtering and evaporation method
Polycrystalline and single-crystal CuInSe/sub 2/ has been grown by the hybrid sputtering and evaporation process. The solar cells were 0.08 cm/sup 2/. The maximum conversion efficiency recorded was 8.4% with V/sub oc/=392 mV, J/sub SC/=33.9 mA, and a fill factor of 63.1%. Single-crystal CuInSe/sub 2/ thin films were deposited on GaAs
Properties of a monopivot centrifugal blood pump manufactured by 3D printing
An impeller the same geometry as the impeller of a commercial monopivot cardiopulmonary bypass pump was manufactured using 3D printing. The 3D-printed impeller was integrated into the pump casing of the commercially available pump to form a 3D-printed pump model. The surface roughness of the impeller, the hydraulic performance, the axial displacement of the rotating impeller, and the hemolytic properties of the 3D-printed model were measured and compared with those of the commercially available model. Although the surface roughness of the 3D-printed model was significantly larger than that of the commercially available model, the hydraulic performance of the two models almost coincided. The hemolysis level of the 3D-printed model roughly coincided with that of the commercially available model under low-pressure head conditions, but increased greatly under high-pressure head conditions, as a result of the narrow gap between the rotating impeller and the pump casing. The gap became narrow under high-pressure head conditions, because the axial thrust applied to the impeller increased with increasing impeller rotational speed. Moreover, the axial displacement of the rotating impeller was twice that of the commercially available model, confirming that the elastic deformation of the 3D-printed impeller was larger than that of the commercially available impeller. These results suggest that trial models manufactured by 3D printing can reproduce the hydraulic performance of the commercial product. However, both the surface roughness and the deformation of the trial models must be considered to precisely evaluate the hemolytic properties of the model.