Back Interface and Absorber Bulk Deep-Level Trap Optimization Enables Highly Efficient Flexible Antimony Triselenide...

The unique 1D crystal structure of Antimony Triselenide (Sb₂Se₃) offers notable potential for use in flexible, lightweight devices due to its excellent bending characteristics. However, fabricating high-efficiency flexible Sb₂Se₃ solar cells is challenging, primarily due to the suboptimal contact interface between the embedded Sb₂Se₃ layer and the molybdenum back-contact, compounded by complex intrinsic defects. This study introduces a novel Molybdenum Trioxide (MoO₃) interlayer to address the back contact interface issues in flexible Sb₂Se₃ devices. Further investigations indicate that incorporating a MoO₃ interlayer not only enhances the crystalline quality but also promotes a favorable [hk1] growth orientation in the Sb₂Se₃ absorber layer. It also reduces the barrier height at the back contact interface and effectively passivates harmful defects. As a result, the flexible Sb₂Se₃ solar cell, featuring a Mo-foil/Mo/MoO₃/Sb₂Se₃/CdS/ITO/Ag substrate structure, demonstrates exceptional flexibility and durability, enduring large bending radii and multiple bending cycles while achieving an impressive efficiency of 8.23%. This research offers a straightforward approach to enhancing the performance of flexible Sb₂Se₃ devices, thereby expanding their application scope in the field of photovoltaics.