title: Synthesis of blue emitting InP/ZnS quantum dots through control of competition between etching and growth.
abstract: Blue (<480 nm) emitting Cd-free quantum dots (QDs) are in great demand for various applications. However, their synthesis has been challenging. Here we present blue emitting InP/ZnS core/shell QDs with a band edge emission of 475 nm and a full width at half maximum of 39 nm (215 meV) from their quantum confined states. The drastic temperature drop immediately after mixing of the precursors and holding them at a temperature below 150 °C was the critical factor for the synthesis of blue emitting QDs, because the blue QDs are formed by the etching of ultra-small InP cores by residual acetic acid below 150 °C. Etching was dominant at temperatures below 150 °C, whereas growth was dominant at temperatures above 150 °C. ZnS shells were formed successfully at 150 °C, yielding blue emitting InP/ZnS QDs. The colour of the InP/ZnS QDs depicted on the CIE 1931 chromaticity diagram is located close to the edge, indicating a pure blue colour compared to other InP-based QDs.
authors.affiliation: Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea.
authors.forename: Kipil
authors.initials: K
authors.lastname: Lim
authors.forename: Ho Seong
authors.initials: HS
authors.lastname: Jang
authors.forename: Kyoungja
authors.initials: K
authors.lastname: Woo