Synthesis and Assembly of Core–Shell Nanorods with High Quantum Yield and Linear Polarization

• Published in: Advanced functional materials Vol. 33; no. 49
• Main Authors: Zeng, Yicheng, Su, Huixue, Liu, Yuan, Chen, Weiwei, Liu, Fangze, Gao, Hanfei, Wu, Yuchen, Manna, Liberato, Li, Hongbo
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.12.2023
• Subjects: Assembly; Cadmium selenides; confined assemblies; core–shells; Emission analysis; Light emitting diodes; Linear polarization; Liquid crystal displays; Liquid phases; Materials science; Nanocrystals; nanorod superstructures; Nanorods; Phosphines; polarized emission; Quantum dots; Quantum efficiency; Seeds
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202306091

The seeded growth method offers an efficient way to design core–shell semiconductor nanocrystals in the liquid phase. The combination of seed and shell materials offers wide tunability of morphologies and photophysical properties. Also, semiconductor nanorods (NRs) exhibit unique polarized luminescence which can potentially break the theoretical limit of external quantum efficiency in light emitting diodes based on spherical quantum dots. Although rod‐in‐rod core–shell NRs present higher degree of polarization, most studies have focused on dot‐in‐rod core–shell NRs due to the difficulties in achieving uniform NR seeds. Here, this study prepares high‐quality uniform CdSe NRs by improving the reactivity of the Se source, using a secondary phosphine, namely diphenylphosphine, to dissolve the Se power, along with the conventional tertiary phosphine, namely trioctylphosphine. Starting from these high‐quality NR seeds, this study synthesizes CdSe/CdxZn1−xS/ZnS core–shell NRs with narrow emission bandwidth (29 nm at 620 nm), high PLQY (89%) and high linear polarization (p = 0.90). This study then assembles these core–shell NRs using the confined assembly method and fabricates long‐range‐ordered microarrays with programmable patterns and displaying highly polarized emission (p = 0.80). This study highlights the great potential of NRs for application in liquid crystal displays and full‐color light emitting diodes displays. Highly uniform CdSe nanorods are synthesized by using a secondary phosphine. Based on these high‐quality nanorod seeds, rod‐in‐rod CdSe/CdxZn1−xS/ZnS nanorods with narrow emission bandwidth, high photoluminescence quantum yield and high linear polarization are synthesized. Using the confined assembly method, these nanorods are assembled into long‐range‐ordered microarrays with programmable patterns and display highly polarized emission.