苏州大学Xue-Dong Wang团队通过对母核工程化，利用激发态分子内质子转移（ESIPT）将六能级体系激光推向900nm。这一研究成果发表在2022年10月11日出版的国际学术期刊《德国应用化学》上。

在该研究中，团队建立了一种分子设计策略，通过扩展ESIPT母核的π共轭体系来增强级联的双ESIPT过程，从而实现红移六能级体系激光。具体而言，团队设计并合成了以1,9-二羟基蒽为核心的ESIPT模型分子，通过DFT计算和超快动力学分析，证明了该模型分子可以经历两次级联ESIPT过程，而1,8-二羟基蒽为基础的类似物只能经历一次ESIPT过程。最后，研究人员以该分子为基础，在只有27.4 μJ cm^-2的低阈值下实现了900 nm的六能级系统激光。

研究人员表示，具有ESIPT过程的有机分子因其有效的四能级体系而被认为是近红外有机激光器的理想增益材料。然而，利用现有的ESIPT活性增益材料将激光波长扩展到800 nm以上仍然是一个挑战。

附：英文原文

Title: Excited-State Intramolecular Proton Transfer Parent Core Engineering for Six-Level System Lasing Toward 900 nm

Author: Chang-Cun Yan, Yan-Ping Liu, Wan-Ying Yang, Jun-Jie Wu, Xue-Dong Wang, Liang-Sheng Liao

Issue&Volume: 2022-10-11

Abstract: Organic molecules which can undergo excited-state intramolecular proton transfer (ESIPT) process have been considered as ideal gain materials for near-infrared organic lasers owing to their effective four-level systems. However, extending lasing wavelength beyond 800 nm with present ESIPT-active gain materials is still in challenge. Herein, we established a molecular design strategy that operates via extending the π-conjugated system of the ESIPT parent core to enhance the cascaded double ESIPT process and thus to achieve the red-shifted six-level system lasing. Concretely, a model molecule with 1,9-dihydroxyanthracene as the ESIPT parent core was designed and synthesized, which was proved to undergo twice cascaded ESIPT processes while the 1,8-dihydroxynaphthalene-based analogue can only undergo once ESIPT process based on DFT calculations and ultrafast dynamics analyses. Finally, a six-level system lasing toward 900 nm was achieved with a low threshold of 27.4 μJ cm  2  .

DOI: 10.1002/anie.202210422

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202210422