SETO FY2020 – Photovoltaics

Arizona State University

Project Name: The Role of Hydrogen in the Performance and Long-Term Stability of High-Efficiency Silicon Cells and Modules
Location: Tempe, AZ
DOE Award Amount: $2,000,000
Awardee Cost Share: $500,000
Principal Investigator: Mariana Bertoni
Project Summary: Module reliability has typically been measured by ethylene vinyl acetate (EVA) yellowing, corrosion, delamination and backsheet cracking. This project examines the main drivers of degradation at the cell level, many of which stem from hydrogen incorporation into the structures. The project team is working to understand and model the effects of hydrogen in various layers of the cell and at its critical interfaces by testing hydrogen under external stressors in order to extend the performance of these architectures for successful use as tandem subcells.

Clemson University

Project Name: Tool for Reliability Assessment of Critical Electronics in PV (TRACE-PV)
Location: N. Charleston, SC
DOE Award Amount: $1,600,000
Awardee Cost Share: $440,000
Principal Investigator: Zheyu Zhang
Project Summary: Field data from PV power plant operators shows that power electronics converters cause between 43% and 70% of the service calls. This project is developing a Tool for Reliability Assessment of Critical Electronics in PV (TRACE-PV), which can predict service life, examine physics-to-failure mechanisms, and assess solar energy costs. The team will validate and demonstrate the accuracy and broad applicability of the TRACE-PV tool through accelerated life testing, field reliability data, and case studies considering various PV techniques. This project will enable PV inverter developers to understand reliability bottlenecks so they can improve next-generation designs and evaluate the efficacy of new techniques on inverter reliability. Additionally, it will enable utility-scale PV operators to fairly quantify PV inverter reliability, assess the remaining useful life of inverters under operation, and schedule maintenance in advance.

Georgia Institute of Technology

Project Name: Development of ~ 25% Efficient Double Side Screen Printed Poly-Si/SiOx Passivated Contact Solar Cells
Location: Atlanta, GA
DOE Award Amount: $1,500,000
Awardee Cost Share: $380,000
Principal Investigator: Ajeet Rohatgi
Project Summary: Very few contact layers for silicon (Si) PV cells can achieve efficiency higher than 25% at a lower cost than Passivated Emitter and Rear Contact (PERC). One promising candidate to surpass PERC is Tunnel Oxide Passivated poly-Si/SiOx contacts (TOPCon), but currently these contacts can only be used on the back side of Si PV cells rather than both sides. This is because the TOPCon layer absorbs some sunlight before it reaches the active PV material, which decreases the cell’s efficiency. It is also expensive to screen-print TOPCon layers on very thin poly-Si layers. Recently, the project team succeeded in making a double-sided screen-printed TOPCon Si PV cell with ≥ 22% efficiency. The team will use these methods to screen-print TOPCon layers on thin (≤ 20 nm) poly-Si layers. They will also improve the TOPCon layer itself by decreasing charge recombination and incorporating oxygen to expand its bandgap, which will reduce the amount of sunlight it absorbs. If successful, the team will produce a low-cost, commercial-ready ≥ 24.5% efficient Si PV cell with double-side screen-printed TOPCon layers.

University of Central Florida

Project Name: Project Name: Developing PID Susceptibility Models for Bifacial PV Module Technologies
Location: Orlando, FL
DOE Award Amount: $1,500,000
Awardee Cost Share: $500,000
Principal Investigator: Joseph Walters
Project Summary: Bifacial PVs are predicted to account for more than a 50% share of the PV market by 2026. This project team is constructing a bifacial cell that is significantly different than the aluminum back surface field cells that have dominated the bifacial PV market in years past. These bifacial cells will be incorporated into bifacial modules as well as monofacial modules. The team will analyze how this novel cell construction is affected by high-voltage conditions by measuring its performance and developing corresponding models to characterize any degradation caused by the high voltage.

University of Central Florida

Project Name: Gaining Fundamental Understanding of Critical Failure Modes and Degradation Mechanisms in Fielded Photovoltaic Modules via Multiscale Characterization
Location: Orlando, FL
DOE Award Amount: $2,000,000
Awardee Cost Share: $510,000
Principal Investigator: Kristopher Davis
Project Summary: This project applies multiscale characterization methods to field-exposed PV modules to link observed performance degradation to specific loss mechanisms and, ultimately, to root causes. This research will examine a large and diverse population of modules to ensure statistical relevance. The team will perform multiple iterations of down-selection, beginning with large-scale analysis of voltage data, followed by the application of both traditional and novel onsite characterization methods. The analysis will be used to select modules for further characterization in a controlled lab setting, then to make assessments on the root cause of observed failure modes and degradation mechanisms. From those modules, individual regions of interest will be identified for targeted materials characterization to provide final confirmation of the root cause.

University of Delaware

Project Name: In-Situ Antimony Doped Polycrystalline CdTe Films for Simplified Cell Processing and Maximized Energy Yield
Location: Newark, DE
DOE Award Amount: $2,000,000
Awardee Cost Share: $500,000
Principal Investigator: Brian McCandless
Project Summary: This project is advancing CdTe solar cell open circuit voltage and reliability through antimony-doped CdTe cells. The team will conduct theoretical defect calculations, analysis, and modeling to simplify cell fabrication and improve cell performance and reliability. The project results will reduce the cost of solar energy by eliminating module processing steps and increasing reliability over deployment time.

University of Maryland: College Park

Project Name: Integrated Approach to Ancillary PV Component Reliability Assessment
Location: College Park, MD
DOE Award Amount: $1,500,000
Awardee Cost Share: $410,000
Principal Investigator: Patrick McCluskey
Project Summary: This project is developing an integrated approach to assessing the reliability of power electronic components in PV systems. The new approach is based on the development of physics-informed degradation models embedded in digital twins, or digital replicas of power electronic components, then validated with accelerated life testing and field data. The team will record the causes of abnormal behavior in power electronic devices and the amount of time taken to reach failure, then calibrate and validate against accelerated life testing, field performance, and reliability data collected by PV systems.

University of Washington

Project Name: Forecasting Perovskite Photovoltaic Device Performance using Dark-Field Imaging and Machine Learning
Location: Seattle, WA
DOE Award Amount: $1,500,000
Awardee Cost Share: $380,000
Principal Investigator: Hugh Hillhouse
Project Summary: PV devices combining low-cost, high power conversion efficiency with low degradation rates are necessary in order to achieve more affordable solar energy. Hybrid perovskites (HPs) are expected to achieve this goal, though long-term stability is a concern due to several degradation pathways. This project is developing accurate forecasting models for device performance lifetime of state-of-the-art all-perovskite tandem solar cells using machine learning models that will account for device-to-device variation. The forecasting model will predict the tandem power-conversion efficiency under standard operating conditions, which will be validated with new conformal prediction methods, along with comparison to in-the-field device monitoring. The forecasting models will also provide important data that will improve device architecture and encapsulation strategies to extend the performance lifetime.