Colloidal semiconductor nanocrystals (NCs) are favorable candidates for solution-processed, next generational optoelectronics such as solar cells and photodetectors. Pb- and Cd-chalcogenide semiconductors are the most widely studied and well understood types nanocrystals, but there is a strong need to expand to less-toxic materials to minimize safety hazards and achieve compliance with regulatory directives. AgBiS2 is a promising material towards this aim, but there is interest in formulating solution processing strategies to exchange long-chain, electrically insulating ligands at NC surfaces with shorter ligands to improve charge transport upon assembly of thin films, which is tyically undertaken in a solid-state, layer-by-layer fashion that comprimises scalability. To address these challenges, we demonstrate a fast solution phase ligand exchange process to generate AgBiS2 NC inks using a cinnamic acid derivative as an additive that accelerates the phase transfer to polar solvents. Photoconductivity in thin films assembled from the AgBiS2 NC inks is achieved using a single deposition step, avoiding multiple layer iterations undertaken in solid-state ligand methods. The inks remain colloidally stable after several days, and photoconductor devices showcase fast response times <4 ms, high on/off ratios ~20, and film conductivities of ~3×10–8 S/cm, highlighting the promise in completely solution processed optoelectronics using eco-friendly materials.

Photoconductive thin films composed of environmentally benign AgBiS2 Iinks obtained through a rapid phase transfer process

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.