Е-Публикации
Технически университет - София

Abstract: This paper investigates the implementation of potassium niobate (KNbO3) as an inorganic buffer layer in flexible perovskite solar cells (F-PSCs) to enhance performance and stability. The study aims to use KNbO3's piezoelectric properties and its ability to form oxygen vacancies to reduce interface energy barriers and improve charge extraction. Vacuum-deposited KNbO3 films of varying thicknesses (0-40 nm) were integrated into F-PSCs, and how the film thickness affects the open-circuit voltage (Voc), short-circuit current (Jsc), and power conversion efficiency (PCE) was investigated. Results show that while increasing electron transporting layer's thickness can initially improve Voc and Jsc, excessive thickness leads to reduced performance due to increased series resistance and hindered charge extraction. The optimal KNbO3 thickness was found to be around 30 nm, achieving a maximum PCE of 22.3%. Additionally, the study examines the impact of oxygen vacancies in KNbO3 films on device conductivity and performance, revealing that controlled oxygen vacancies enhance charge transport. The findings suggest that KNbO3 effectively stabilizes F-PSCs, as demonstrated by thermal and mechanical stability tests, exhibiting 84 % retention of the initial PCE after thermal treatment at 75 °C and 10 000 mechanical bends.

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