Researchers from China's Zhejiang University, Westlake University, Southern University of Science and Technology, Chinese Academy of Sciences (CAS) and University of California Los Angeles in the U.S have reported a family of high-entropy organic–inorganic hybrid perovskites for photovoltaic applications.
The scientists built, for the first time, an inverted perovskite solar cell relying on a high-entropy hybrid perovskite material. The result is a device with an improved open-circuit voltage and fill factor, due to reduced non-radiative recombinations and optimized interface.
The research team explained that the new material has a multicomponent single-phase perovskite structure, which ensures superior phase stability at high temperatures compared to conventional perovskites. The coexistence of multiple organic cations in the proposed material was confirmed by nuclear magnetic resonance (NMR) spectroscopy.
Using the high entropy hybrid perovskite (HEHP), the researchers created a perovskite film that is said to exhibit superior water and damp-heat resistance. With this film, they constructed a perovskite solar cell with a conventional architecture based on an indium tin oxide (ITO) substrate, a tin oxide (SnO2) electron transport layer (ETL), the perovskite absorber, a hole transport layer based on Spiro-OMeTAD, and a silver (Ag) metal contact. Its performance was compared to a reference device with a similar perovskite film without the HEHP.
Tested under standard illumination conditions, the HEHP-based device achieved a power conversion efficiency of 25.7%, an open-circuit voltage of 1.17 V, a short-circuit current density of 25.8 mA cm2, and a fill factor of 85.2%. The reference device reached an efficiency of 23.2%, an open-circuit voltage of 1.13 V, a short-circuit current density of 25.1 mA cm2, and a fill factor of 81.7%.
The HEHP-based cell was also found to be able to retain over 98% of its initial efficiency after 1,000 h.
The scientists attributed the enhancement in open-circuit voltage and fill factor to reduced non-radiative recombinations and improved interface after the incorporation of HEHP. They postulated that the superiority of HEHP over single component in reducing electronic disorders could be attributed to the coexistence of multiple types of A-site cations that can synergistically interact with various defects.
The team believes that the novel perovskite material is applicable in different perovskite compositions and cell architectures and may someday be used as a universal and error-tolerant strategy to improve the performance of perovskite solar cells.
