Coupled Organic-Inorganic Nanostructures with Mixed Organic Linker Molecules

The electronic properties of semiconducting inorganic lead sulfide (PbS) nanocrystals (NCs) and organic linker molecules are dependent on the size of NCs as well as the used ligands. Here, we demonstrate that a weakly binding ligand can be successfully attached to PbS NCs to form a coupled organicinorganic nanostructure (COIN) by mixing with a strong binding partner. We use the weakly binding zinc beta-tetraaminophthalocyanine (Zn4APc) in combination with the strongly binding 1,2ethanedithiol (EDT) as a mixed ligand system and compare its structural, electronic, and (photo-)electrical properties with both single-ligand COINs. It is found that binding of Zn4APc is assisted by the presence of EDT leading to improved film homogeneity, lower trap density, and enhanced photocurrent of the derived devices. Thus, the mixing of ligands is a versatile tool to achieve COINs with improved performance.

Automated summary

The electronic properties of semiconducting inorganic lead sulfide (PbS) nanocrystals and organic linker molecules depend on the size of the nanocrystals and the ligands used. Mixing a weakly binding ligand with a strong binding partner can successfully create coupled organic-inorganic nanostructures. This study demonstrated that using a mixed ligand system improved the film homogeneity, reduced trap density, and enhanced photocurrent of the derived devices, making it a versatile tool for achieving COINs with improved performance.