New bifacial linker enhances adhesion in flexible solar cells

Flexible perovskite solar cells (F-PSCs) have attracted attention for their potential in diverse applications. However, their commercialization faces challenges related to low mechanical flexibility, which leads to poor adhesion between the perovskite absorber layer and the flexible substrate.

A recent study published in Advanced Materials offers a promising solution to this problem with the development of a novel bifacial linker designed to prevent heterointerfacial delamination in F-PSCs. This study was conducted by Prof. Yang Dong and Prof. Liu Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS).

Researchers introduced a novel bifacial linker, potassium benzyl(trifluoro)borate (BnBF₃K), to enhance the adhesion at the SnO₂/perovskite interface, which effectively addresses the delamination issue in F-PSCs.

By optimizing heterointerfacial delamination, minimizing buried defects in the perovskite, reducing SnO₂ surface defects, and improving physical contact between the perovskite and the SnO₂-coated substrate, the performance of the solar cells was significantly enhanced.

Further analysis confirmed the crucial role of the bifacial linker in boosting device performance. The unique properties of BnBF₃K facilitated strong molecular interactions and robust adsorption, ensuring excellent adhesion between the perovskite and the SnO₂ substrate.

The strengthened mechanical interface provided a stable foundation for electrical contact, allowing efficient charge extraction and transport, even under mechanical deformation of the flexible device.

As a result of the bifacial linker, an efficiency of 21.82% (certified at 21.39%) was achieved for a flexible perovskite solar module with an area of 12.80 cm². Moreover, the flexible modules demonstrated excellent mechanical flexibility, retaining 96.56% of their initial efficiency after 6,000 bending cycles, highlighting their potential for a wide range of practical applications.

“Our study not only improves the mechanical stability of flexible perovskite devices but also reduces buried surface defects and optimizes energy level alignment,” said Prof. Liu.