Zero‐Dimensional Organic–Inorganic Hybrid Copper‐Based Halides with Highly Efficient Orange–Red Emission

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2021-10, Vol.17 (42), p.e2103831-n/a
• Main Authors: Fang, Shaofan, Li, Henan, Xie, Yuelin, Li, Huixia, Wang, Ye, Shi, Yumeng
• Format: Article
• Language: English
• Subjects: Color; Copper; copper‐based halides; Excitons; Halides; high quantum yield; Light emitting diodes; Lighting; light‐emitting diode; Metal halides; Nanotechnology; perovskites; red light; Toxicity
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202103831

Lead‐free metal halides are promising luminescent materials with low non‐toxicity, tunable emission, and high luminescence quantum yield (PLQY). The development of red light‐emitting materials with high PLQY to meet the color coordinate requirements for light‐emitting diode (LED) lighting and wide color gamut displays remains a major scientific challenge. Herein, novel lead‐free copper‐based halide materials are reported. PEA4Cu4I4 is an efficient orange–red broad emission with a highest PLQY of 73.6%. All three materials, namely, those of ((R)‐(+)‐α‐PEA)4Cu4I4, ((S)‐(–)‐α‐PEA)4Cu4I4, and (β‐PEA)4Cu4I4 with zero‐dimensional structures have large exciton binding energies and Huang–Rhys factors, thus causing efficient self‐trapped exciton emissions. A prototypical orange–red LED device is fabricated successfully that demonstrates the potential of copper‐based halide materials in lighting and display applications. This study presents three novel lead‐free copper‐based halide materials with zero‐dimensional structures: ((R)‐(+)‐α‐PEA)4Cu4I4, ((S)‐(‐)‐α‐PEA)4Cu4I4, and (β‐PEA)4Cu4I4 (PEA=phenethylamine). These materials have a broad orange‐red emission at ≈630 nm and a high photoluminescence quantum yield (the highest one is 73.6%), which are due to efficient self‐trapped exciton emissions. These results demonstrate the potential in lighting and display applications.