Thrust 3: 2015 Fundamentals for High Efficiency Photovoltaics

Co-leaders: Freundlich and Opila

Nano-based Enablers for Commercial Silicon Solar Cells (Holman)

Nano-anything has had a hard time of it in the solar world in the past few years; an overabundance of optimistic promises and few significant results have led the PV community to be skeptical of “nanobabble.” Nevertheless, we feel that there are real opportunities for nanostructures in solar cells, and the aim of this project is the systematic investigation of the potential of select nanostructures to enhance the efficiency of commercial solar cells. We focus on silicon—the most mature of the commercial technologies—and in particular on the impact of nanostructures on Voc, light absorption and multiple exciton generation.

Multiscale Modeling of Dilute Nitride Materials and Silicon Heterojunction Solar Cells (Goodnick, Vasileska)

The goal of this project is to develop multi-scale models for quantum engineered semiconductor heterostructures and devices based on dilute nitrogen containing alloys of III-V compound semiconductors to enable improved efficiencies and manufacturability for multi-junction applications. Also, the project will work to develop a simulator that captures the physics of interfacial transport in heterojunction Si solar cells in a realistic fashion, which can be generalized to different heterojunction systems for full 2D and 3D solar cell structures.

Defect Creation in Epitaxial Structures: Structural Investigations, Simulation of Defect Creation (Faleev, Honsberg)

The main goal of this project is the investigation of the initial stage of defect creation: creation of pre-dislocation clusters, the main predecessor of dislocation loops in the volume of epitaxial structure. Detailed investigations of structural transformation of crystalline defects during epitaxial growth and their correlation with growth conditions are also planned. Based on the knowledge of fundamental structural features, the main correlations between crystalline perfection and physical properties of epitaxial structures, which directly affect device performance, will be investigated.

Advanced Optical Design/Demonstration for High Energy Yield for Spectrum Splitting and Low Concentration PV Systems (Kostuk)

The overarching goal of this work is to utilize optical methods to integrate the different PV cell technologies developed in QESST into high efficiency low cost PV systems. This project will address a variety of topics in optics as a step towards realizing this goal. Specifically the work focuses on high efficiency spectrum splitting and high energy yield low concentration systems. The most promising designs will be fabricated and evaluated to test their performance.

Cu(InGa)Se₂ Tandem Cell Development (Shafarman, Birkmire)

The primary goals are to demonstrate the feasibility of thin film tandem cells based on Cu(InGa)Se₂ alloy materials to increase module efficiency with an approach for low cost manufacturing and to develop the fundamental basis for improving cell efficiencies. The research will include improved performance of wide bandgap cells which are the critical enabling technology for tandems using novel co-evaporated (AgCu)(InGa)Se₂ alloys, manufacturing issues for thin films which will develop models for high rate / continuous processing and validate reactor design based on these models, and fundamental characterization of novel materials for Cu(InGa)Se₂ tandem cells with a focus on advanced photoemission and x-ray methods to study surface and grain boundary properties.