Selection and characterisation of weakly coordinating solvents for semiconductor electrodeposition

Area of Science:

• Electrochemistry
• Materials Science
• Organic Chemistry

Background:

• Weakly coordinating solvents like dichloromethane are crucial for electrodepositing p-block semiconductors.
• Developing new solvents is essential for advancing electronic device applications.
• Solvent properties significantly influence electrochemical processes and material properties.

Purpose of the Study:

• To utilize solvent descriptors to identify novel weakly coordinating solvents for electrochemistry.
• To establish criteria for selecting suitable solvents for electrodeposition applications.
• To compare candidate solvents against dichloromethane for semiconductor electrodeposition.

Main Methods:

• Employed Kamlet and Taft's solvent parameters (π*, α, β) to define weakly coordinating solvents.
• Identified candidate solvents based on polarity (π* ≥ 0.55) and weak coordination (α, β ≤ 0.2).
• Evaluated solvents via voltammetric window, conductivity, differential capacitance, and model redox couple electrochemistry.

Main Results:

• Five candidate solvents (trifluorotoluene, o-dichlorobenzene, p-fluorotoluene, chlorobenzene, 1,2-dichloroethane) were identified and compared.
• Ion pairing was identified as a key factor in weakly coordinating solvents.
• o-dichlorobenzene and 1,2-dichloroethane demonstrated the most promise due to their polarity.

Conclusions:

• Solvent descriptors provide a robust method for identifying new weakly coordinating solvents.
• o-dichlorobenzene and 1,2-dichloroethane are suitable alternatives to dichloromethane for semiconductor electrodeposition.
• This research expands the solvent toolkit for fabricating advanced electronic materials.