Printed assemblies of microscale triple‐junction inverted metamorphic GaInP/GaAs/InGaAs solar cells

• Published in: Progress in photovoltaics 2019-06, Vol.27 (6), p.520-527
• Main Authors: Gai, Boju, Geisz, John F., Friedman, Daniel J., Chen, Huandong, Yoon, Jongseung
• Format: Article
• Language: English
• Subjects: Assemblies; Cost effectiveness; Gallium arsenide; Glass substrates; III‐V; Indium gallium arsenides; inverted metamorphic; Layouts; microcells; Modules; multijunction solar cells; Photovoltaic cells; Solar cells; Transfer printing
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.3127

Inverted metamorphic (IMM) multijunction solar cells represent a promising material platform for ultrahigh efficiency photovoltaic systems (UHPVs) with a clear pathway to beyond 50% efficiency. The conventional device processing of IMM solar cells, however, typically involves wafer bonding of a centimeter‐scale die and destructive substrate removal, thereby imposing severe restrictions in achievable cell size, type of module substrate, spatial layout, as well as cost effectiveness. Here, we report material design and fabrication strategies for microscale triple‐junction IMM (3J IMM) Ga0.51In0.49P/GaAs/In0.26Ga0.74As solar cells that can overcome these difficulties. Specialized schemes of delineation and undercut etching enable the defect‐free release of microscale IMM solar cells and printed assemblies on a glass substrate in a manner that preserves the growth substrate, where efficiencies of 27.3% and 33.9% are demonstrated at simulated AM1.5D one‐ and 351 sun illumination, respectively. A composite carrier substrate where released IMM microcells are formed in fully functional, print‐ready configurations allows high‐throughput transfer printing of individual IMM microcells in a programmable spatial layout on versatile choices of module substrate, all desired for CPV applications. We report materials design and fabrication strategies for microscale triple‐junction inverted metamorphic (3J IMM) Ga0.51In0.49P/GaAs/In0.26Ga0.74As solar cells that allow the defect‐free release of IMM microcells and printed‐assembly on a glass substrate in a manner that preserves the growth substrate. A composite carrier substrate where 3J IMM microcells are formed in fully‐functional, releasable configurations enables high‐throughput transfer printing of individual IMM devices in a programmable spatial layout on versatile choices of module substrate, all desired for CPV applications.