In recent years, heavy metals have been widely used in manufacture, agriculture and pharmaceutical industry. Human activities also cause frequent occurrence of heavy metal pollution. Therefore, prevention and control of heavy metal pollution has become a worldwide topic. The heavy metals are widely distributed in atmosphere, soil and water. In water, they are mainly in the form of cation. Therefore, the efficient detection of heavy metal ions is of important in the research of the prevention and control of heavy metal contamination. Among numerous detection methods, as a simple and effective method, the fluorescence sensing has received extensive attention. At present, the fluorescent sensors are mainly based on the fluorescent probes used in solutions and embedded in on-surface films. In the development of fluorescence sensing based on solution phase, graphene quantum dots (GQDs) have become a hot research subject because they are superior in terms of low toxicity, excellent photostability, high surface area, chemical inertness and high biocompatibility. As for the fluorescence sensing based on solid phase, fabrication of the ordered array of fluorescent probes on solid substrates makes sense for improving the performance of sensing device. In this thesis, we explored the above mentioned two kinds of detection modes, respectively with systematical discussion of the possibility of application of 0D GQDs and 2D molecular self-assemblies on HOPG in the fluorescence sensing of heavy metal ions. The correlation between the structures and optical properties of materials was studied and revealed. The primary contents of the thesis are as follows:First, regarding the fluorescence detection of heavy metal ions in solution phase, we developed a facile top-down preparation of GQDs featured with acid vapour cutting process. A series of novel fluorescent GQDs have been fabricated by using confined nanoreator and precursors with heteroatoms. High-yield synthesis of GQDs with good aqueous solubility via simple, low-cost and fast separation process and utilized for accurate FL detection of Fe3+ were achieved. This section includes three chapters: 1. A low-cost top-down synthesis of GQDs using a SBA-15 template as a confined nanoreactor via a HNO3 vapor cutting and in-situ filtration strategy was presented. With the recyclable ordered mesoporous SBA-15 template enhancing the confined space at nanometer scales, a high-yield (48%) preparation and size-controllable of GQDs has been achieved. Furthermore, application of the obtained GQDs as fluorescent probes for Fe3+ determination was studied. The results showed that the obtained GQDs exhibited high selectivity towards Fe3+. The further study indicate that the fluorescence of the GQD can also be quenched by Cu2+, Co2+, Mn2+, Ni2+ after its surface modification, thus may widen the application of the obtained GQDs.2. By using a nitrogen-rich MOF-derived porous carbon (ZIF-8C) with large specific surface area as precursor, N-GQDs with uniform particle size and abundant superficial functional groups were obtained via the acid vapour cutting strategy. The obtained N-GQDs were used as a platform for the selective and rapid detection of ferric ions with a low detection limit of 80 nM. It is expected that the facile strategy presented in this study can be extended to the synthesis of GQDs doped with other heteroatoms upon an appropriate selection of initial MOF-derived carbon as raw material and also will expand the scope of application of MOF-based materials.3. Two nitrogen and sulfur co-doped GQDs (N, S-GQDs) with different particle sizes and heights were synthesized via HNO3 vapour cutting with a porous polythiophene-derived carbon via serving as the sulfur source and the HNO3 vapour presenting as the scissor and the nitrogen source. The as-prepared N, S-GQDs exhibited blue and yellow-green colored fluorescence. An application of the obtained greenish-yellow N, S-GQDs for highly selective and sensitive fluorescent detection of Fe3+ was demonstrated, with a larger linear range of 0-130 μM than the above two GQDs and a low detection limit of 70 nM. The present rapid achievement of the dual heteroatoms doped GQDs with tunable fluorescence may be applied for biomedical imaging, energy conversion, light-emitting devices and so on.Second, regarding the fluorescence detection of heavy metal ions in solid phase, we fabricated 2D fluorescent assembled film by immobilizing organic functional molecule or host-guest architecture on highly oriented pyrolytic graphite (HOPG) via self-assembly, which remain fluorescence emission of fluorescence molecule, achieving immobilizion of fluorescent probes, provide basis for development of fluorescent film sensors. This section includes three chapters: 1. The fluorescent probe TPE-C4-L2 with well known aggregation-induced emission (AIE) property was selected to fabricate 2D assembled film on HOPG. With the aid of scanning tunneling microscopy (STM), we investigated the microcosmic structure before and after the addition of Zn(II) and determined its fluorescence (FL) response to Zn(II). The correlation between their optical properties and structures at the molecular level was also revealed. The experimental results demonstrate that metal-ligand coordination is the main factor that caused the change of the SAM structures, leading to a reduced local ordering, and then results in the quenched emission of fluorescence. In this respect, we realized sensing trace amount of Zn(II).2. The luminescent molecule 1-pyrenebutanoic acid (PBA) was introduced into a host template 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB) on HOPG substrate to construct a well-organized 2D nanoarray film. The structural arragment and optical property of the PBA/TCDB network on air/HOPG interface were investigated employing STM and fluorescence spectroscopy. The experimental results show that the SAM on HOPG not only can retain fluorescence emission, but also the FL intensity changed to be very stable in atmosphere condition in contrast to oxygen-induced fluorescence quenching of PBA in solution. The interesting results of such nanoarray film inspired us to explore its potential application in preparation of more stable and highly ordered films and optical devices for sensing other species in the future. In this thesis, a series of GQDs were prepared using a HNO3 vapor cutting strategy and applied for the specific fluorescence detection of Fe3+ in solution. And the fluorescent sensing properties of GQDs was improved by heteroatom doping. In the aspect of solid detection, we achieved immobilized film of fluorescent probes and host-guest complex by self-assembly and accomplished the stimulating detection or provided potential for determining metal ions. In a word, both the sensing studies on GQDs and investigations of functional molecules array on HOPG revealed that structures of materials have the direct influence on fluorescence characteristics.