Researchers from China's Southern University of Science and Technology, Shanghai Jiao Tong University, City University of Hong Kong and Australia's Western Sydney University have reported a breakthrough in advancing the stability and performance of perovskite solar cells (PSCs). While solution processing offers a low-cost pathway for scalable PSC manufacturing, the instability of perovskite materials - particularly during solution ageing in air - has long hindered consistent device efficiency and commercial viability.
The team systematically investigated the rapid degradation of FA-rich perovskite precursor solutions when exposed to air, finding that oxidative reactions, especially iodine generation, severely compromise film quality. To overcome this, they introduced a multifunctional additive, 4-(trifluoromethyl) phenylhydrazine (TFPH), which effectively stabilizes the perovskite in both its solution and solid phases.
TFPH achieves this through a combination of chemical and structural mechanisms: the hydrazine group suppresses oxidative decomposition by acting as a redox-active stabilizer, while the trifluoromethyl group enhances dipole interactions that guide crystal orientation, relax lattice strain, and improve film morphology. Together, these effects reduce impurity levels and defect density, resulting in highly uniform and durable perovskite layers.
When TFPH was incorporated into perovskite precursor solutions, the resulting PSCs consistently delivered power conversion efficiencies around 26.0%, irrespective of ageing time. Even more notably, the devices exhibited exceptional operational stability, maintaining over 92% of their initial efficiency after 1830 hours of continuous operation under the ISOS-L-3 protocol.
These findings demonstrate that TFPH not only mitigates degradation during solution storage but also enhances long-term device performance and reproducibility across fabrication batches.
Beyond its immediate performance benefits, the molecular design of TFPH presents a broader framework for stabilizing various perovskite compositions, from standard to narrow- and wide-bandgap systems. It also opens opportunities for synergistic applications with other stabilizers, such as polymer additives or interfacial modifiers, to further optimize device lifetime and resilience.
By revealing the fundamental mechanisms driving perovskite precursor degradation and proposing a practical, scalable solution, this work represents a potential step toward industrial-scale manufacturing of high-efficiency, stable perovskite solar cells.
