A series of copper halide based inorganic-organic hybrid semiconductors have been synthesized. Structural analysis confirms that all compounds are composed of one-dimensional Cu4X62- anionic chains that coordinate to cationic ligands via Cu-N dative bonds. Different coordination affinities of the ligands lead to two types of ligand arrangements with various structural distortions. All compounds are highly resistant to heat and moisture as a result of the combination of coordinate and ionic bonds. Low energy emission with high efficiency is achieved for these compounds and the emission energy (∼552-615 nm) and color (yellow-orange) can be tuned by varying the ligand and halogen element. The electronic structure and luminescence mechanism are examined by both experimental and theoretical methods. More importantly, all compounds demonstrate good solubility in polar aprotic solvents, a desired property that is absent in all other CuX hybrid families of extended structures, which is attributed primarily to the ionic nature of this material class. The good solution-processability, and cost effective and easily scalable synthesis coupled with high quantum efficiencies and framework stability make these hybrid materials promising phosphors for general lighting applications.

Three new one-dimensional (1D) All-In-One (AIO) type CuI-based hybrid semiconductors with both dative and ionic bonds between the inorganic and organic components have been successfully designed and synthesized by using the ligands containing both cationic center and coordination available sites. Structural analysis confirms that all compounds share the same formula of Cu4I6(L)2 (L ​= ​ligand) and are composed of 1D-Cu4I62− anionic chains that coordinate to cationic ligands. These materials demonstrate high stability towards heat and moisture and excellent solution processability due to their unique bonding nature. They emit low energy light ranging from green to orange color (530–590 ​nm). The origin and mechanism of their emissions were studied by both experimental and theoretical methods. More importantly, all compounds can be easily fabricated into films by solution process, a desired but rare feature for most of CuI-based hybrids built of extended networks.

Inorganic semiconductor materials are best known for their superior physical properties, as well as their structural rigidity and stability. However, the poor solubility and solution-processability of these covalently bonded network structures has long been a serious drawback that limits their use in many important applications. Here, we present a unique and general approach to synthesize robust, solution-processable, and highly luminescent hybrid materials built on periodic and infinite inorganic modules. Structure analysis confirms that all compounds are composed of one-dimensional anionic chains of copper iodide (Cu_mI_m+2^2-) coordinated to cationic organic ligands via Cu-N bonds. The choice of ligands plays an important role in the coordination mode (μ¹-MC or μ²-DC) and Cu-N bond strength. Greatly suppressed nonradiative decay is achieved for the μ²-DC structures. Record high quantum yields of 85% (λ_ex = 360 nm) and 76% (λ_ex = 450 nm) are obtained for an orange-emitting 1D-Cu₄I₆(L₆). Temperature dependent PL measurements suggest that both phosphorescence and thermally activated delayed fluorescence contribute to the emission of these 1D-AIO compounds, and that the extent of nonradiative decay of the μ²-DC structures is much less than that of the μ¹-DC structures. More significantly, all compounds are remarkably soluble in polar aprotic solvents, distinctly different from previously reported CuI based hybrid materials made of charge-neutral Cu_mX_m (X = Cl, Br, I), which are totally insoluble in all common solvents. The greatly enhanced solubility is a result of incorporation of ionic bonds into extended covalent/coordinate network structures, making it possible to fabricate large scale thin films by solution processes.

A group of copper iodide-based hybrid semiconductors with the general formula of 2D-CuI(L)0.5 (L = organic ligands) are synthesized and structurally characterized. All compounds are two-dimensional (2D) networks made of one-dimensional (1D) copper iodide staircase chains that are interconnected by bidentate nitrogen-containing ligands. Results from optical absorption and emission experiments and density functional theory (DFT) calculations reveal that their photoluminescence (PL) can be systematically tuned by adjusting the lowest unoccupied molecular orbital (LUMO) energies of the organic ligands. Charge carrier transport measurements were carried out for the first time on single crystals of selected 2D-CuI(L)0.5 structures, and the results show that they possess p-type conductivity with a Hall mobility of ~1 cm2 V-1 s-1 for 2D-CuI(pm)0.5 and 0.13 cm2 V-1 s-1 for 2D-CuI(pz)0.5, respectively. These values are comparable to or higher than the mobilities of typical highly luminescent organic semiconductors. This work suggests that robust, high-dimensional copper iodide hybrid semiconductors are promising candidates to be considered as a new type of emissive layer for light-emitting diode (LED) devices.

Fluorosis has been regarded as a worldwide disease that seriously diminishes the quality of life through skeletal embrittlement and hepatic damage. Effective detection and removal of fluorinated chemical species such as fluoride ions (F^-) and perfluorooctanoic acid (PFOA) from drinking water are of great importance for the sake of human health. Aiming to develop water-stable, highly selective and sensitive fluorine sensors, we have designed a new luminescent MOF In(tcpp) using a chromophore ligand 2,3,5,6-tetrakis(4-carboxyphenyl)pyrazine (H₄tcpp). In(tcpp) exhibits high sensitivity and selectivity for turn-on detection of F^- and turn-off detection of PFOA with a detection limit of 1.3 μg L^-1 and 19 μg L^-1, respectively. In(tcpp) also shows high recyclability and can be reused multiple times for F^- detection. The mechanisms of interaction between In(tcpp) and the analytes are investigated by several experiments and DFT calculations. These studies reveal insightful information concerning the nature of F^- and PFOA binding within the MOF structure. In addition, In(tcpp) also acts as an efficient adsorbent for the removal of F^- (36.7 mg g^-1) and PFOA (980.0 mg g^-1). It is the first material that is not only capable of switchable sensing of F^- and PFOA but also competent for removing the pollutants via different functional groups.