A highly emissive AIE-active luminophore exhibiting deep-red to near-infrared piezochromism and high-quality lasing

• Published in: Chemical science (Cambridge) Vol. 11; no. 15; pp. 47 - 415
• Main Authors: Lv, Chunyan, Liu, Wangwang, Luo, Qing, Yi, Haiyan, Yu, Huakang, Yang, Zhongmin, Zou, Bo, Zhang, Yujian
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 03-04-2020; The Royal Society of Chemistry
• Subjects: Charge transfer; Chemistry; Crystallography; Decay rate; Energy gap; Epoxy resins; Fluorescence; Lasing; Photoluminescence; Self-assembly
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d0sc01095b

Further development of high-efficiency and low-cost organic fluorescent materials is intrinsically hampered by the energy gap law and spin statistics, especially in the near-infrared (NIR) region. Here we design a novel building block with aggregation-induced emission (AIE) activity for realizing highly efficient luminophores covering the deep-red and NIR region, which originates from an increase in the orbital overlap and electron-withdrawing ability. An organic donor-acceptor molecule (
BPMT
) with the building block is prepared and can readily form J-type molecular columns with multiple C-H N/O interactions. Notably, such synthesized materials can emit fluorescence centered at 701 nm with extremely high photoluminescence quantum yields (PLQYs) of 48.7%. Experimental and theoretical investigations reveal that the formation of the hybridized local and charge-transfer (HLCT) state and substantial C-H N/O interactions contribute to a fast radiative decay rate and a slow nonradiative decay rate, respectively, resulting in high PLQYs in the solid state covering the NIR range. Remarkably, such
BPMT
crystals, as a first example, reveal strong-penetrability piezochromism along with a distinct PL change from the deep-red (
λ
max
= 704 nm) to NIR (
λ
max
= 821 nm) region. Moreover, such typical AIE-active luminophores are demonstrated to be a good candidate as a lasing medium. Together with epoxy resin by a self-assembly method, a microlaser is successfully illustrated with a lasing wavelength of 735.2 nm at a threshold of 22.3 kW cm
−2
. These results provide a promising approach to extend the contents of deep-red/NIR luminophores and open a new avenue to enable applications ranging from chemical sensing to lasing.
A HLCT-type luminophore is prepared with bright deep-red fluorescence, showing high-performance piezochromism and lasing.