Dear Colleagues,

Organic–inorganic hybrid materials are, in general definition, materials whose structure is formed by both organic and inorganic moieties interacting with each other at the molecular scale through weak interactions such as hydrogen bonding, van der Waals forces, electrostatic interactions, or by strong coordinative or covalent bonds. The interest in acquiring this category of materials lies in extending and bettering the material properties without compromising the desired existing ones. Compared with their individual counterparts, hybrid materials can demonstrate better properties; inorganic materials can play various roles viz.  enhancing thermal and mechanical stability, controlling the refractive index, providing an accessible and interconnected porous network for sensing or catalysts, or contributing specific magnetic, electronic, redox, electrochemical or chemical properties. Organic components, on the other hand, greatly modify mechanical properties, thus enabling the production of films and fibers by contributing to a specific physical or chemical property, including electrical or optical characteristics, electrochemical behavior, chemical or biochemical reactivity, etc.

This Special Issue on organic–inorganic hybrid metal cluster compounds will center on organic–inorganic hybrid materials and their utilization as optical and electronic functional materials for the development of new technologies. Mostly, we will focus on organic–inorganic hybrid materials containing polymers as one of the components, which will widen the scope of hybrid materials for diverse areas of applications.

For the improvement of hybrid photovoltaic systems of inorganic semiconductors and conducting polymers: (i) the right combination of inorganic and organic semiconductors should be chosen; (ii) the LUMO of the conducting polymer needs to be aligned with the conducting band of the inorganic semiconductor; or (iii) the bandgap of the inorganic semiconductor can be tuned by the quantum confinement effect. In addition, an optimal bandgap of ~1.5 eV is suggested for conducting polymers in the hybrid system because such a bandgap may balance a large enough absorption of sunlight (and, thus, a good photocurrent) and a high enough photovoltage output. In addition, nanostructures should be used to provide a large interface for the enhancement of the charge separation process, but at the same time the structural design also has to consider the connection in each component to facilitate charge transportation. Thus, long nanorods/nanotubes, branched nanopods, or a porous network may be utilized, and to accelerate the charge transportation, an ordered nanorod/nanotube array can be considered. The comprehensive depiction and discussion of a variety of hybrid functional organic–inorganic materials and their contribution to the design of specific modern technologies is the prime focus of this Special Issue.

Dr. Shailesh Narain Sharma
Dr. Parth Vashishtha
Guest Editors

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• organic–inorganic
• hybrid materials
• metal clusters
• polymers
• photovoltaics
• quantum confinement
• functional materials
• optoelectronic properties