High-Entropy Hybrid Perovskite Solar Cells Achieve 25.7% Efficiency

Researchers at Zhejiang University in China have developed an inverted perovskite solar cell based on a high-entropy hybrid perovskite (HEHP) material. This novel approach reportedly enhances the device's stability and exhibits exceptional efficiency.

"Our work highlights the potential of a high-entropy hybrid perovskite (HEHP) structure to improve the efficiency and stability of perovskite solar cells," said Jingjing Xue, the study's corresponding author. "This structure features highly disordered organic components that provide entropy gain and exhibit better thermal stability and structural robustness compared to their ordered single-component counterparts. The chemical richness of the organic components offers further possibilities for tuning the properties of perovskites and related materials."

Improved Stability and Efficiency

The research team demonstrated that the new material possesses a single-phase multicomponent perovskite structure, offering greater phase stability at high temperatures than conventional perovskites. Nuclear magnetic resonance (NMR) spectroscopy confirmed the coexistence of different organic cations in the proposed material.

"The HEHP single crystal showed characteristic peaks of all organic cations that matched well with those of an equimolar mixture of all five organic cations," the scientists explained. "This single crystal can best be described as a hybrid structure composed of ordered inorganic structures and disordered organic interlayers."

Enhanced Device Construction

Using HEHP, the researchers created a perovskite film with excellent resistance to water and moisture. This film was then used to build a perovskite solar cell with a conventional architecture, which included an indium tin oxide (ITO) substrate, an electron transport layer (ETL) of tin oxide (SnO2), the perovskite absorber, a spiro-OMeTAD-based hole transport layer, and a metallic silver (Ag) contact. The performance of this device was compared to a reference device with a similar perovskite layer but without HEHP.

Superior Performance Metrics

Tested under standard lighting conditions, the HEHP-based device achieved:

• Efficiency: 25.7%
• Open-circuit voltage: 1.17 V
• Short-circuit current density: 25.8 mA/cm²
• Fill factor: 85.2%

In comparison, the reference device achieved:

• Efficiency: 23.2%
• Open-circuit voltage: 1.13 V
• Short-circuit current density: 25.1 mA/cm²
• Fill factor: 81.7%

The HEHP-based cell retained over 98% of its original efficiency even after 1,000 hours.

"We attribute the improvement in open-circuit voltage and fill factor to the reduction of nonradiative recombination and interface improvement after incorporating HEHP," the scientists explained. "The superiority of HEHP over individual components in reducing electronic interference could be attributed to the coexistence of multiple types of A-site cations that can interact synergistically with various defects."

Broad Applicability

The team is confident that the new perovskite material can be utilized in various perovskite compositions and cellular architectures. "It can serve as a universal and defect-tolerant strategy to improve the performance of perovskite solar cells in different scenarios, which is critical for improving the production yield of perovskite devices in future industrial mass production," the team concluded.

Details of this new cell concept are reported in the study "High-entropy hybrid perovskites with disordered organic moieties for perovskite solar cells," published in Nature Photonics.