Bis(stearoyl) Sulfide: A Stable, Odor-Free Sulfur Precursor for High-Efficiency Metal Sulfide Quantum Dot Photovoltaics

The synthesis of metal sulfide nanocrystals is a crucial step in the fabrication of quantum dot (QD) photovoltaics. Control over the QD size during synthesis allows for precise tuning of their optical and electronic properties, making them an appealing choice for electronic applications. This flexibility has led to the implementation of QDs in both highly-efficient single junction solar cells and other optoelectronic devices including photodetectors and transistors. Most commonly, metal sulfide QDs are synthesized using the hot-injection method utilizing a toxic, and air- and moisture-sensitive sulfur source: bis(trimethylsilyl) sulfide ((TMS)(2)S). Here, bis(stearoyl) sulfide (St(2)S) is presented as a new type of air-stable sulfur precursor for the synthesis of sulfide-based QDs, which yields uniform, pure, and stable nanocrystals. Photovoltaic devices based on these QDs are equally efficient as those fabricated by (TMS)(2)S but exhibit enhanced operational stability. These results highlight that St(2)S can be widely adopted for the synthesis of metal sulfide QDs for a range of optoelectronic applications.

Automated summary

The synthesis of metal sulfide nanocrystals is essential for quantum dot (QD) photovoltaics. The control over QD size allows for precise tuning of optical and electronic properties, making them suitable for various electronic applications. A new air-stable sulfur precursor, bis(stearoyl) sulfide (St(2)S), is introduced for sulfide-based QD synthesis, resulting in uniform and stable nanocrystals. Photovoltaic devices based on St(2)S-synthesized QDs exhibit comparable efficiency to those using the toxic, air- and moisture-sensitive sulfur source (TMS)(2)S, but have improved operational stability.