Scientists from the National Renewable Energy Laboratory (NREL) and the University of Louisville have achieved a significant breakthrough in solar cell technology. They have successfully constructed an inverted perovskite solar cell with an electron transport layer (ETL) using yttrium-doped tin oxide (SnO2) nanoparticles. This development opens up new possibilities for efficient and cost-effective solar cell production.
The researchers highlighted the numerous advantages of SnO2-based ETLs, including their ability to be processed at low temperatures, excellent photostability, high chemical stability, strong electronic conductivity, good optical transparency, wide band gap, and favorable band alignment with perovskites. Furthermore, the wide and adjustable optical band gap and deep conduction band of SnO2 enable optimal charge injection.
To enhance the electronic properties of SnO2 nanoparticles, the scientists synthesized yttrium-doped SnO2 nanoparticles. This modification improved the performance of the solar cell while maintaining the low-temperature annealing conditions required for fabricating perovskite cells on Polyethylene terephthalate (PET) substrates.
The solar cell possesses a p-i-n architecture and an active area of 0.1 cm2. It utilizes a flexible PET and indium tin oxide (ITO) substrate, a poly-triarylamine (PTAA) hole transport layer (HTL), a PFN polymer interfacial layer, a perovskite absorber, a yttrium-doped SnO2 ETL, a bathocuproine (BCP) buffer layer, and a silver (Ag) metal contact.
The various layers, including PTAA, PFN, perovskite, and SnO2, were deposited using a one-step blade coating method, while BCP and silver were deposited through thermal evaporation.
In testing, the researchers subjected several cells to standard illumination conditions and observed a notable outcome. These cells achieved a power conversion efficiency of 16.5%, an open-circuit voltage of 1.08 V, a short-circuit current of 22.40 mA/cm2, and a fill factor of 68.4%. For comparison, a reference device without yttrium doping in the ETL achieved an efficiency of 14.3%, an open-circuit voltage of 1.01 V, a short-circuit current of 22.40 mA/cm2, and a fill factor of 63.3%.
The improved performance of the solar cell can be attributed to the innovative SnO2 ETL design. The researchers noted that this material offers cost-effective scalability and manufacturing advantages over traditional organic ETLs, thereby enhancing the competitiveness of commercial perovskite solar modules.
The details of this groundbreaking achievement were published in the research paper titled “High Performing Inverted Flexible Perovskite Solar Cells via Solution Phase Deposition of Yttrium-Doped SnO2 Directly on Perovskite” in the journal Applied Energy Materials. This development holds great promise for the future of solar energy and could revolutionize the solar cell industry.
