苏州大学Liang-Sheng Liao研究小组经过不懈努力，用可定制有机电荷转移共晶在近红外(II)窗口实现双模光电子学。这一研究成果发表在2024年4月22日出版的国际学术期刊《美国化学会杂志》上。

该研究首先提出了一种利用分子间电荷转移相互作用，驱动BF_XTQ系列(X = 0,1,2,4)共晶吸收和发射光谱红移的共晶策略，使光谱位于近红外(II)窗口，并将光学带隙减小到~0.98 eV。值得注意的是，这些基于BF_XTQ的光电器件可以表现出双模光电特性。对一系列基于BF_XTQ的光电探测器的研究表明，在375 ~ 1064 nm的探测率(D*)超过10¹³ Jones，在1064 nm的探测率最大值为1.76 × 10¹⁴ Jones。

此外，共晶内CT激子的辐射跃迁触发了1000 nm以上的近红外发射，光致发光量子产率(PLQY)约为4.6%，以及950 nm处光损耗系数低至0.0097 dB/μm的光波导行为。这些结果促进了一种新兴的共晶方法，在微/纳米尺度近红外多功能光电子学中的发展。

据介绍，有机分子由于其可定向性和易于大规模生产，而被认为是近红外(NIR)光电活性材料的理想候选者。然而，受复杂的分子设计和严格的能隙规律的限制，在第二近红外(NIR (II))区域实现具有窄带隙要求的光电器件面临更多挑战。

附：英文原文

Title: Customizable Organic Charge-Transfer Cocrystals for the Dual-Mode Optoelectronics in the NIR (II) Window

Author: Yue Yu, Xing-Yu Xia, Chao-Fei Xu, Zhao-Ji Lv, Xue-Dong Wang, Liang-Sheng Liao

Issue&Volume: April 22, 2024

Abstract: Organic molecules have been regarded as ideal candidates for near-infrared (NIR) optoelectronic active materials due to their customizability and ease of large-scale production. However, constrained by the intricate molecular design and severe energy gap law, the realization of optoelectronic devices in the second near-infrared (NIR (II)) region with required narrow band gaps presents more challenges. Herein, we have originally proposed a cocrystal strategy that utilizes intermolecular charge–transfer interaction to drive the redshift of absorption and emission spectra of a series BFXTQ (X = 0, 1, 2, 4) cocrystals, resulting in the spectra located at NIR (II) window and reducing the optical bandgap to ～0.98 eV. Significantly, these BFXTQ-based optoelectronic devices can exhibit dual-mode optoelectronic characteristics. An investigation of a series of BFXTQ-based photodetectors exhibits detectivity (D*) surpassing 1013 Jones at 375 to 1064 nm with a maximum of 1.76 × 1014 Jones at 1064 nm. Moreover, the radiative transition of CT excitons within the cocrystals triggers NIR emission over 1000 nm with a photoluminescence quantum yield (PLQY) of ～4.6% as well as optical waveguide behavior with a low optical-loss coefficient of 0.0097 dB/μm at 950 nm. These results promote the advancement of an emerging cocrystal approach in micro/nanoscale NIR multifunctional optoelectronics.

DOI: 10.1021/jacs.4c00648

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c00648