Synthesis and elementary carrier processes of highly efficient blue-emissive semiconductor quantum dots by interfacial engineering

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02578
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 28030:Nanomaterials-related
• Research Institution: Kwansei Gakuin University
• Principal Investigator: TAMAI Naoto 関西学院大学, 理学部, 教授 (60163664)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 半導体量子ドット / 半導体ナノプレートレット / 青色発光 / 多励起子過程 / オージェ再結合

Outline of Final Research Achievements

For the development of high-quality semiconductor quantum dots (CQDs) in the blue region, we prepared several CQDs using various materials by colloidal synthetic methods. In addition, femtosecond pump-probe spectroscopy capable of measuring up to ultraviolet region was developed to analyze the elementary exciton dynamics of CQDs by a nonlinear crystal out of phase matching condition. It was found that highly luminescent ZnSe CQDs were synthesized by using a zinc source with a short alkyl chain. We also synthesized one-dimensional quantum confinement materials such as ZnSe nanoplatelets (NPLs) with an emission in the ultraviolet region and blue-emitting Zn-based Cd1-xZnxSe NPLs by cation exchange of CdSe NPLs. We analyzed the exciton dynamics of blue-emitting CQDs and NPLs by femtosecond transient absorption spectroscopy, and examined the relationship between multiple exciton interactions such as Auger recombination and nanocrystal size and/or composition.

Free Research Field

物理化学

Academic Significance and Societal Importance of the Research Achievements

青色領域に発光を示す半導体CQDsは，次世代半導体EL材料の素材として期待されており，質の高いCQDs合成が重要である。本研究では種々の青色発光CQDsのコロイド合成を試み，短鎖アルキル基を持つ亜鉛源を用いると質の高いCQDsが得られること，発光バンド幅の狭いZn系Cd1-xZnxSe青色発光NPLsをCdSe NPLsのカチオン交換により合成できることを示した。また，多励起子の関与するオージェ再結合やホットキャリア緩和，ZnSe CQDs発光の温度依存性を解明した。これらの研究は，青色発光半導体ナノ結晶の基本的な光学特性の解明だけでなく，LED開発に於いて重要な基盤となる。