High‐Efficiency Flexible GaAs/InGaAs Dual‐Junction Solar Cells Fabricated by Metallic Nanoparticle‐Based Wafer Bonding

• DOI: 10.1002/sstr.202400421
• Publication Date: 2024-09-20T05:20:11Z
• Authors: Yeongho Kim; Suho Park; Thuy Thi Nguyen; Jiyeon Jeon; Byong Sun Chun; Sang Jun Lee
• Keywords: Wafer Bonding

Multijunction solar cells made from highly lattice‐mismatched (LMM) material systems offer an optimal bandgap combination for the ultrahigh conversion of energy to electricity. Conventional fabrication techniques multijunction cells, such as metamorphic epitaxy, direct wafer bonding, and adhesive are still expensive produce low yields owing use complex process steps sophisticated equipment. Herein, flexible GaAs/In 0.53 Ga 0.47 As dual‐junction with a large lattice mismatch 3.7% between subcells fabricated using indium‐tin‐oxide (ITO) nanoparticle‐based bonding process. The ITO layer electrically optically connecting GaAs top InGaAs bottom shows series resistance 5.7 × 10 −2 Ω cm high optical transmission 90% in infrared range 870–1800 nm. dark current characteristic ITO‐bonded cell exhibits good rectifying behavior on–off ratio ≈10 5 at ±2 V. Under 1 sun AM 1.5G illumination, power efficiency 28.5% is achieved two‐terminal series‐connected cell, average external radiative 2.6%. In these findings, it suggested that may be facile cost‐effective route fabricating LMM potentially overcoming Shockley–Queisser limit.