Researchers from LONGi Green Energy, Soochow University, Xi'an Jiaotong University and other institutions recently proposed a dual-buffer-layer strategy with a stress-release mechanism to synergistically mitigate ion bombardment during subsequent sputtering deposition and enhance interfacial adhesion while preserving efficient charge extraction. The loose SnOx buffer layer, engineered by adjusting the purging time of atomic layer deposition, can dissipate strain energy, whereas the compact SnOx layer can ensure robust electrical contact.
Based on this dual-buffer-layer, the flexible tandem solar cell, constructed on a 60-micron thick ultra-thin silicon bottom cell, achieved a certified PCE of 33.4% on 1-cm2 area, and an certified PCE of 29.8% on wafer-sized area of 260-cm2 with a power-per-weight of up to 1.77 W/g.
The modified tandem solar cells demonstrated good durability, retaining over 97% of their initial power conversion efficiencies after 43000 bending cycles under a maximum curvature radius of around 40 mm in air, and around 97% after thermal cycling testing (−40 °C to 85 °C) for 250 cycles.
