Researchers have made significant strides in enhancing the efficiency and stability of perovskite solar cells (PSCs) by successfully utilizing solvent-dripping modulated 3D/2D heterostructures. The latest findings reveal how the controlled integration of two-dimensional (2D) perovskite on top of three-dimensional (3D) perovskite layers can mitigate interfacial recombination and impede ion migration, thereby improving both performance and durability.
Despite the promise of 3D perovskites, their susceptibility to defects and changes under operational conditions has hindered their widespread commercial application. Traditionally, defects at grain boundaries create pathways for ion migration, which leads to performance degradation over time. The innovative approach introduced in this study employs meta-amidinopyridine (MAP) ligands to form highly ordered 2D perovskite layers atop the 3D perovskite films, which enhances stability and efficiency.
The result? Solar cells achieved a record maximum power conversion efficiency (PCE) of 26.05%, with certified values at 25.44%. What’s more, under damp heat tests, the encapsulated devices retained 82% of their initial PCE after 1,000 hours and 75% after 840 hours of outdoor testing conditions.
The methodology involves dissolving the MAP ligands in polar solvents like isopropanol (IPA), which, when spin-coated onto pre-deposited 3D perovskite layers and subjected to thermal annealing, led to the formation of the desired 2D perovskite domains. This technique worked effectively compared to previous approaches where disordered structures negatively impacted charge transfer.
A key aspect of the new method was the solvent post-dripping step, which enables the removal of unreacted 2D ligands and helps to fine-tune the orientation of the developed layers. Traditionally, the excess unreacted ligands reduce efficiency by creating energetic disorder and impeding charge transport, but the new approach demonstrates how post-dripping can significantly improve the structural integrity of the interfaces.
Analysis through techniques such as grazing-incidence wide-angle X-ray scattering (GIWAXS) confirmed the successful formation of phase-pure 2D perovskite structures. With the MAP-treated samples exhibiting enhanced characteristics, the study showed clear improvements over control devices, which highlighted the viability of using this ligand and technique.
The researchers' work suggests broader applicability beyond just 3D/2D perovskite structures; they found the methodology could be adapted for other ligands, enhancing the versatility of this approach. This discovery is particularly significant as it aligns with the pressing need for efficient and durable solar technologies, which are integral to addressing global energy demands and climate change.
Further studies will undoubtedly expand on these techniques and explore their potential scalability, as the researchers also demonstrated successful integration with larger-area devices. This step not only shows promise for wider application but also serves to validate the methodology for mainstream manufacturing.
Overall, the developments surrounding solvent-dripping modulated 3D/2D heterostructures mark a pivotal step forward for perovskite solar cell technology, indicating not only higher efficiencies but also improved long-term operational reliability. Such advancements could be the key to unlocking broader adoption of this promising solar technology.