Recently, the research team led by Associate Prof. Xie Liqiang and Prof. Wei Zhanhua from the Institute of Luminescent Materials and Information Displays and the School of Materials Science and Engineering of Huaqiao University (HQU), in collaboration with Goldstone (Fujian) Energy Co., Ltd, published its research paper titled “Efficient and Stable Monolithic Perovskite/Silicon Tandem Solar Cells Enabled by Contact Resistance-Tunable Indium Tin Oxide Interlayer” in Advanced Material, a top international journal in materials science under Wiley Publishing (2024 impact factor: 27.4).

Tandem solar cells have garnered widespread attention for their potential to surpass the Shockley-Queisser limit of single-junction solar cells. Perovskite/silicon tandem solar cells are an emerging technology that combines the excellent optoelectronic properties of perovskite with the performance of mainstream industrial silicon-based solar cells. In recent years, the rapid progress of perovskite/silicon tandem solar cells has resulted in impressive conversion efficiencies. However, the imperfect charge behavior at the perovskite/electron transport layer (ETL)/transparent conductive oxide (TCO) interface limits the performance enhancement of perovskite/silicon tandem solar cells. TCOs, such as indium tin oxide (ITO) and indium zinc oxide (IZO), are typically prepared by sputtering. Due to the high-energy sputtering particles, directly depositing TCOs on fullerene (C60) ETLs may cause severe sputtering damage to the ETL and perovskite layers. Therefore, a protective layer is needed to ensure high interface quality. Moreover, imperfect charge behavior due to energy level mismatch, carrier recombination, and high contact resistance at the ETL/TCO interface can lead to significant energy loss of photogenerated carriers. Thus, to minimize interfacial energy loss and avoid sputtering damage, it is crucial to construct a semiconductor intermediate layer with energy level matching and adjustable contact resistance at the ETL/TCO interface.

In this research, an electron beam evaporation (EBE) deposited indium tin oxide intermediate layer with adjustable composition was used to effectively regulate the contact resistance with the transparent conductive electrode (TCO) and optimize the interface contact. This approach ultimately achieved a certified conversion efficiency of 30.3% in a 1 cm² perovskite/silicon two-terminal tandem solar cell. This novel interface layer holds great potential for perovskite/silicon tandem solar cells and other tandem cells with perovskite as the top layer, marking a significant step towards the commercial application of perovskite/silicon tandem solar cells.

This research was conducted under the guidance of Associate Prof. Xie Liqiang and Prof. Wei Zhanhua, with substantial support from Goldstone (Fujian). HQU doctoral students Jin Yongbin, Feng Huiping, and Fang Zheng co-first authored the paper. The research was sponsored by the National Natural Foundation of China, the Natural Science Foundation of Fujian Province and the Scientific Research Fund of Huaqiao University.

Link to the paper: https://onlinelibrary.wiley.com/doi/10.1002/adma.202404010

（Editor：Wei Linying）