Blending Ionic and Coordinate Bonds in Hybrid Semiconductor Materials: A General Approach toward Robust and...

Area of Science:

• Materials Science
• Inorganic Chemistry
• Solid-State Chemistry

Background:

• Inorganic semiconductor materials offer superior physical properties but suffer from poor solubility and solution-processability due to their rigid, covalently bonded structures.
• This limitation hinders their application in various fields, necessitating the development of processable alternatives.

Purpose of the Study:

• To synthesize novel, solution-processable, and highly luminescent hybrid materials based on inorganic modules.
• To investigate the structure-property relationships, particularly focusing on ligand effects on coordination modes and luminescence.

Main Methods:

• Synthesis of hybrid materials using copper iodide (CuI) and tailored organic ligands.
• Structural analysis to determine coordination modes (μ1-MC or μ2-DC) and bonding.
• Photoluminescence (PL) spectroscopy to evaluate quantum yields and temperature-dependent emission properties.
• Solubility tests in various solvents.

Main Results:

• Successfully synthesized one-dimensional (1D) anionic chains of copper iodide coordinated to organic ligands, forming robust hybrid materials.
• Achieved significantly suppressed nonradiative decay in μ2-DC structures, leading to record high quantum yields (up to 85%).
• Demonstrated remarkable solubility in polar aprotic solvents, a significant improvement over previously insoluble CuI-based materials.
• Confirmed the contribution of phosphorescence and thermally activated delayed fluorescence to the emission, with μ2-DC structures showing less nonradiative decay.

Conclusions:

• The developed approach yields highly luminescent and solution-processable inorganic-organic hybrid materials.
• Ligand design is crucial for controlling coordination, bond strength, and luminescence efficiency, with μ2-DC structures being particularly promising.
• The enhanced solubility opens avenues for large-scale thin-film fabrication via solution processing, expanding the application scope of CuI-based materials.