Ligand (biochemistry)

Physics

Receptor

Nanotechnology

Organic chemistry

Surface energy

Crystallography

Surface modification

Engineering

Perovskite (structure)

X-ray photoelectron spectroscopy

Physical chemistry

Atomic physics

Chemical physics

Inorganic chemistry

Chemistry

Materials science

Iodide

Molecule

Ultraviolet photoelectron spectroscopy

Monolayer

Electron affinity (data page)

Photoluminescence

Energetics

Chemical engineering

Optoelectronics

Biochemistry

Binding energy

Thermodynamics

ACS Energy Letters

Surface ligand treatment provides a promising approach for passivating defect states, improving material and device stability, manipulating interfacial energetics, and improving the performance of perovskite solar cells (PSCs). To facilitate targeted selection and design of surface ligands for PSCs, it is necessary to establish relationships between ligand structure and perovskite surface properties. Herein, surface ligands with different binding groups are investigated to determine their extent of surface coverage, whether they form a surface monolayer or penetrate the perovskite, how they influence material energetics and photoluminescence, and how this combination of factors affects PSC performance. Ultraviolet and inverse photoelectron spectroscopy measurements show that surface ligands can significantly shift the ionization energy and electron affinity. These changes in surface energetics substantially impact PSC performance, with the performance decreasing for ligands that create less favorable energy landscapes for electron transfer from MAPbI3 to the electron transport layer, C60.

Surface Ligands for Methylammonium Lead Iodide Films: Surface Coverage, Energetics, and Photovoltaic Performance