Temperature dependence of dark current properties of InGaAs/GaAs quantum dot solar cells

Self-assembledIn₀.₅Ga₀.₅As/GaAsquantum dotsolar cell (QDSC) was grown by metal organic chemical vapor deposition. Systematic measurements of dark current versus voltage (I-V) characteristics were carried out from 30 to 310 K. Compared with the reference GaAssolar cell, the QDSC exhibits larger dark current however its ideality factor (n) was smaller, which cannot be straightly interpreted by the conventional diode models. These results are important for the fundamental understanding of QDSC properties and further implementation of new solar cell designs for improved efficiency.The authors would like to acknowledge financial support from the Australian Research Council and facility support from the Australian National Fabrication Facility ACT node

Omnidirectional Current Enhancement From Laminated Moth-Eye Textured Polymer Packaging for Large-Area, Flexible III-V Solar Modules

Epitaxial lift-off (ELO) processes have allowed for cheaper development of mechanically flexible, ultra-thin, and high- efficiency III-V solar cells. ELO solar cells are natural candidates for applications where solar cells must conform to curved surfaces and provide high efficiency and high specific power generation (W/kg). Such examples include power generation for unmanned aerial vehicles, electric vehicles, and portable electrical power. However, when considering these mobile solar applications, large variations in angle of incidence (AOI) that inevitably occur can greatly decrease overall system efficiency due to significant Fresnel reflections. In this article, we demonstrate the integration of moth- eye antireflection nanostructures on the polymer packaging layer of ELO solar cell arrays using a low-cost, colloidal self-assembly process. The moth-eye structures mitigate Fresnel reflections and increase photocurrent generation over all measured angles of inci- dence relative to ELO solar cell arrays with traditional untextured polymer packaging. The nanostructures survive a commercial lam- ination procedure, an important criterion that must be met to ensure the feasibility of integration into commercial processing. Outdoor solar characterization measurements are performed and, under direct optical illumination, moth-eye textured solar cell ar- rays show a maximum Isc enhancement of ∼58% at 79° AOI rela- tive to traditional untextured polymer packaged solar cell arrays, and when exposed to both direct and diffuse optical illumination a maximum Isc enhancement of ∼23% at 79° AOI is observed.Center for Dynamics and Control of Material

The influence of InGaAs quantum dots on GaAs P-I-N solar cell dark current properties

An analysis of the temperature dependent dark current and spectral response characteristics of an In0.5Ga0.5As/GaAs quantum dot solar cell has been performed to determine the dominant physical processes that lead to a reduction of the open circuit voltage compared with reference single junction GaAs solar cells