Boosting the Efficiency of 1.84 eV Wide-Bandgap Perovskites Photovoltaics Beyond 19% via Yb Engineering.

Phase segregation remains one of the most critical challenges limiting the performance and long-term operational stability of wide-bandgap perovskite solar cells (PSCs). This issue is especially pronounced in 1.84 eV wide-bandgap (WBG) perovskites, where severe halide phase segregation leads to compositional heterogeneity and accelerated device degradation.

Ionic Liquid Top Surface Engineering: In Situ GIWAXS Insights Into 1D/3D Heterojunction Perovskite Formation.

Low-dimensional perovskites have been demonstrated repeatedly to improve the performance of perovskite photovoltaic devices in both light-to-electricity conversion efficiency and device durability. In this work, the ionic liquid (IL) 1-ethyl-3-methylimidazolium hydrogen sulfate (EMIMHSO) is innovatively introduced as a capping layer, which interacts with the residual PbI on the 3D perovskite top surface to generate the 1D perovskite, EMIMPbI. By adjusting the concentration of the IL, 1D perovskite formations with distinct morphologies is achieved.

Composite SnO-KS ETL for energy level regulation and electron mobility enhancement in perovskite solar cells.

High-performance perovskite solar cells commonly utilize SnO as the electron transport layer (ETL), which is vital for perovskite crystallization and defect regulation, yet energy level mismatch, oxygen vacancies in SnO, and defects at the buried interface impede the device's photovoltaic performance. Therefore, we found that incorporating KS into the SnO layer effectively regulated the energy levels and occupied oxygen vacancies, enhancing the electron mobility of the composite SnO-KS ETL and improving the interface quality to promote efficient electron extraction and transport. Consequently, the device based on SnO-KS ETL showed an enhanced photovoltaic performance with power conversion efficiency of to 23.

PTAA-Based Perovskite Photovoltaics Catching up: Ionic Liquid Engineering-Assisted Crystallization Through Sequential Deposition.

PTAA as a widely studied polymeric hole transporting material, has garnered significant attention due to its outstanding thermal and chemical stability. However, the performance of PTAA-based p-i-n devices is shown to lag behind counterpart utilizing oxides or SAMs. In this study, the ionic liquid, 1-ethyl-3-methylimidazolium formate (EMIMCOOH), is innovatively introduced into the lead iodide (PbI) precursor solution, resulting in a more pronounced mesoporous PbI film with expended pore-size and denser pores.

Hexylammonium Acetate-Regulated Buried Interface for Efficient and Stable Perovskite Solar Cells.

Due to current issues of energy-level mismatch and low transport efficiency in commonly used electron transport layers (ETLs), such as TiO and SnO, finding a more effective method to passivate the ETL and perovskite interface has become an urgent matter. In this work, we integrated a new material, the ionic liquid (IL) hexylammonium acetate (HAAc), into the SnO/perovskite interface to improve performance via the improvement of perovskite quality formed by the two-step method. The IL anions fill oxygen vacancy defects in SnO, while the IL cations interact chemically with Pb within the perovskite structure, reducing defects and optimizing the morphology of the perovskite film such that the energy levels of the ETL and perovskite become better matched.

Two-Step Perovskite Solar Cells with > 25% Efficiency: Unveiling the Hidden Bottom Surface of Perovskite Layer.

While significant efforts in surface engineering have been devoted to the conversion process of lead iodide (PbI) into perovskite and top surface engineering of perovskite layer with remarkable progress, the exploration of residual PbI clusters and the hidden bottom surface on perovskite layer have been limited. In this work, a new strategy involving 1-butyl-3-methylimidazolium acetate (BMIMAc) ionic liquid (IL) additives is developed and it is found that both the cations and the anions in ILs can interact with the perovskite components, thereby regulating the crystallization process and diminishing the residue PbI clusters as well as filling vacancies. The introduction of BMIMAc ILs induces the formation of a uniform porous PbI film, facilitating better penetration of the second-step organic salt and fostering a more extensive interaction between PbI and the organic salt.

Tailoring Ionic Liquid Chemical Structure for Enhanced Interfacial Engineering in Two-Step Perovskite Photovoltaics.

Ionic liquids (ILs) have emerged as versatile tools for interfacial engineering in perovskite photovoltaics. Their multifaceted application targets defect mitigation at SnO-perovskite interfaces, finely tuning energy level alignment, and enhancing charge transport, meanwhile suppressing non-radiative recombination. However, the diverse chemical structures of ILs present challenges in selecting suitable candidates for effective interfacial modification.