Matthew Muller has been a research engineer within the Photovoltaic Performance and Reliability Group since 2008. The focus of his work has included topics such as photovoltaic (PV) soiling, PV surface coating durability, PV and concentrating PV (CPV) module and system performance, thermal modeling, spectral performance modeling, methods for on-sun CPV cell temperature evaluation, solar trackers, IEC standards development, test design, prototyping and design of instrumentation, data acquisition systems, programming, and data analysis. He is a member of the American National Standards Institute and has served as a technical expert within the International Electrotechnical Commission (IEC) Working Group 7. He led the IEC effort to publish the technical specification, TC 62727, and the design qualification standard, IEC 62817 (both covering solar trackers), as well as IEC 62670-3, which standardizes performance measurements and power rating procedures for CPV devices.

Currently, he is focused on developing algorithms for automating PV data quality assurance and extracting fleet-level PV performance trends, moving toward a PV circular economy, and advancing predictive PV soiling models and soiling mitigation strategies.