Yoshinaga Taishu, Shinoda Momoka, Iso Yoshiki, Isobe Tetsuhiko, Ogura Akihiro, Takao Ken-Ichi
Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
ACS Omega. 2021 Jan 7;6(2):1741-1750. doi: 10.1021/acsomega.0c05993. eCollection 2021 Jan 19.
Fluorescent carbon dots (CDs) represent a promising eco-friendly next-generation phosphor. However, most CDs exhibit broad photoluminescence (PL) spectra [full width at half-maximum (fwhm) over 60 nm]; few works on CDs with sharp PL spectra (fwhm less than 40 nm) have been reported. In addition, their syntheses and color tuning require harsh conditions of high temperatures, long reaction times, and high pressures with catalysts. Here, we successfully prepared narrow-bandwidth emissive CDs (fwhm of 27-40 nm) from phloroglucinol in a glycol solvent of 1,2-pentanediol at temperatures as low as 180 °C for a reaction duration of as short as 6 h under ambient conditions without any catalysts via an open reaction system in which dehydration and condensation reactions among phloroglucinol molecules were enhanced. We shifted the emission peak from 463 to 511 nm by selecting seven kinds of solvents with different polarities, that is, emission colors could be tuned from blue to green by taking advantage of fluorescence solvatochromism. The CD-dispersed polymer films showed a similar solvatochromic behavior and sharp PL spectra, verifying the feasibility of applying the CDs to displays with a wide color gamut.
荧光碳点（CDs）是一种很有前景的环保型下一代荧光粉。然而，大多数碳点表现出较宽的光致发光（PL）光谱[半高宽（fwhm）超过60 nm]；关于具有尖锐PL光谱（fwhm小于40 nm）的碳点的研究报道较少。此外，它们的合成和颜色调节需要高温、长反应时间和高压以及催化剂等苛刻条件。在此，我们通过开放反应体系成功地在1,2 - 戊二醇的二醇溶剂中，在180°C的低温下，于环境条件下无任何催化剂的情况下，由间苯三酚制备出窄带宽发射的碳点（fwhm为27 - 40 nm），反应持续时间短至6小时，其中间苯三酚分子间的脱水和缩合反应得到增强。我们通过选择七种不同极性的溶剂将发射峰从463 nm移至511 nm，即利用荧光溶剂化显色作用可将发射颜色从蓝色调至绿色。碳点分散的聚合物薄膜表现出类似的溶剂化显色行为和尖锐的PL光谱，验证了将碳点应用于广色域显示器的可行性。
