Fabrication of gradient band tin oxide electron transport layer using self-separated dual-quantum dots for perovskite solar cells

• Published in: Materials today energy 2024-12, Vol.46, p.101708, Article 101708
• Main Authors: Guo, Yang, Li, Xiabing, Chen, Bo, Tang, Yuan, Wang, Jun, Lu, Hao, Guo, Chunxian, Tong, Shuk-Yin
• Format: Article
• Language: English
• Subjects: Gold quantum dots; Graded energy band; Graphene quantum dots; Perovskite solar cell; Tin oxide
• ISSN: 2468-6069; 2468-6069
• DOI: 10.1016/j.mtener.2024.101708

Constructing a gradient band structure electron transport layer (ETL) and thereby enhancing the performance and stability of perovskite solar cells are an effective approach. Leveraging two types of quantum dots (QDs) with different masses, namely GQDs and Au QDs, along with tin oxide (SnO2) colloidal particles, we successfully prepared an ETL with a gradient band structure. Perovskite solar cells fabricated based on this gradient band ETL achieved a power conversion efficiency (PCE) of 22.2 %, whereas those prepared with a conventional SnO2 ETL yielded only 19.6 % efficiency. Furthermore, under continuous AM 1.5 G and 45 °C temperature illumination for 1000 h, the cells retained 91 % of their initial efficiency. Further investigation revealed that the construction of this gradient band structure effectively compensated for the defects of the SnO2, thereby improving its electrical properties. Additionally, it enhanced the transport and separate ability of charge carriers in the ETL, reducing recombination probabilities. This work provides a simple and effective method for constructing gradient band structures, which not only enhances the performance of perovskite solar cells but also holds promise for other photovoltaic conversion devices. [Display omitted] •Gradient band electron transport layer prepared based on dual-quantum dots.•Compact and grain size of the perovskite layer have been significantly improved.•Gradient band structure enhances 115 % efficiency in modified solar cells.•Uncovered device retains 91 % efficiency after 1000 h of lamp irradiation.