Abstract The polymeric carbon nitride possesses the capability to form graphene like novel nanostructures (nanosheets, QDs etc) owing to its layered structure composed of tri-s-triazine units arranged in graphitic fashion by weak Vander Waals forces. Such nanostructures showed improved optoelectronic properties compared to bulk material making them potential candidates as electrode material, interface layer and active layer additive for various optoelectronic devices. Herein graphitic carbon nitride (g-C3N4) based 2D nanosheets (NS) and 0D Quantum Dots (QDs) were prepared by facile green route and acidification of bulk material respectively. Systematic structural and optical investigation were performed on the prepared nanostructures by various characterization techniques viz. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Atomic force microscopy (AFM), UV–Vis and photoluminescence (PL) to understand their structure-property relationship in details. It was observed that even after exfoliation and acidification the unit chemical structure was preserved both for NS and QDs having thicknesses nearly 3–5 nm (~ 10 layers) for NS and 0.8–1.7 nm for QDs respectively. The g-C3N4 nanostructures showed tunable band gap which increases from 2.78 eV for bulk g-C3N4 to 3.3 eV and 3.58 eV for NS and QDs respectively, as observed from the blue shifted absorption and emission spectrum. Moreover, small Urbach energy (EU) for NS (0.64 eV) and QDs (0.24 eV) and higher stokes shift of QDs compared to bulk counterpart, indicate possibilities for superior charge carrier separation and collection capabilities of such novel nanostructures, making them potential candidate for OPVs and OLEDs applications.

中文翻译：

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剥离的类石墨烯碳氮化物形成纳米片和量子点的结构和光学特性

摘要 聚合氮化碳具有形成石墨烯类新型纳米结构（纳米片、量子点等）的能力，因为其层状结构由三-s-三嗪单元通过弱范德华力以石墨方式排列。与块状材料相比，这种纳米结构显示出改进的光电性能，使其成为各种光电器件的电极材料、界面层和活性层添加剂的潜在候选材料。在本文中，石墨氮化碳 (g-C3N4) 基二维纳米片 (NS) 和 0D 量子点 (QD) 分别通过简便的绿色路线和大块材料的酸化制备。通过各种表征技术对制备的纳米结构进行了系统的结构和光学研究。X 射线衍射 (XRD)、傅里叶变换红外光谱 (FTIR)、透射电子显微镜 (TEM)、原子力显微镜 (AFM)、UV-Vis 和光致发光 (PL) 以详细了解它们的结构-性能关系。据观察，即使在剥离和酸化之后，NS 和 QD 的单位化学结构仍保留，NS 的厚度分别接近 3-5 nm（~10 层），QD 的厚度分别为 0.8-1.7 nm。从蓝移吸收和发射光谱观察，g-C3N4 纳米结构显示可调带隙，从块体 g-C3N4 的 2.78 eV 分别增加到 NS 和 QD 的 3.3 eV 和 3.58 eV。此外，与本体对应物相比，NS (0.64 eV) 和 QD (0.24 eV) 的小 Urbach 能量 (EU) 以及 QD 的更高斯托克斯位移，表明这种新型纳米结构具有卓越的电荷载流子分离和收集能力的可能性，