Red green blue emissive lead sulfide quantum dots: heterogeneous synthesis and applications.

Bo Hou,Jong Min Kim,Young-Woo Lee,John Hong,Jong Bae Park,Sanghyo Lee,Stephen M Morris,Hyunsik Im,Jung Inn Sohn,Byung-Sung Kim,Docheon Ahn,Yuljae Cho,Seungnam Cha

doi:10.1039/c7tc00576h

Abstract

Visible emission colloidal quantum dots (QDs) have shown promise in optical and optoelectronic applications. These QDs are typically composed of relatively expensive elements in the form of indium, cadmium, and gallium since alternative candidate materials exhibiting similar properties are yet to be realized. Herein, for the first time, we report red green blue (RGB) photoluminescences with quantum yields of 18% from earth-abundant lead sulfide (PbS) QDs. The visible emissive property is mainly attributed to a high degree of crystallinity even for the extremely small QD sizes (1-3 nm), which is realized by employing a heterogeneous reaction methodology at high growth temperatures (>170 °C). We demonstrate that the proposed heterogeneous synthetic method can be extended to the synthesis of other metal chalcogenide QDs, such as zinc sulfide and zinc selenide, which are promising for future industrial applications. More importantly, benefiting from the enlarged band gaps, the as-prepared PbS solar cells show an impressive open circuit voltage (∼0.8 V) beyond that reported to date.

Highlights

By controlling the reactivity of the precursors, we have successfully synthesized emissive PbS quantum dots (QDs) that cover the whole visible spectrum
The primary idea underlying the synthesis of the wide band gap PbS QDs is to 3692 | J
As illustrated in Scheme 1, by using this liquid and solid heterogeneous reaction methodology, we have successfully controlled the reaction between the metal and the chalcogen precursors at high temperatures, which enable the synthesis of extremely small size PbS QDs with a high degree of crystallinity (ESI† and Table S1)

Summary

Introduction

By controlling the reactivity of the precursors, we have successfully synthesized emissive PbS QDs that cover the whole visible spectrum. By employing asprepared wide band gap PbS QDs, we demonstrate an outstanding open circuit voltage (Voc) improvement in p–n junction QDSCs. Results and discussion

Results

Conclusion