2D polyphthalocyanines (PPCs) of different structure and polymerization degree: chemical factors, characterization and processability

TL;DR

This study explores how different synthesis conditions affect the structure and properties of 2D polyphthalocyanines, revealing distinct types with varying order, polymerization, and conductivity, characterized mainly by IR spectroscopy.

Contribution

It demonstrates that vapor/solid and liquid/solid interfaces produce different PPC structures at the same temperature, highlighting the role of chemical factors beyond temperature alone.

Findings

Vapor/solid interface yields well-polymerized, ordered PPCs.

Liquid/solid interface produces amorphous, cross-linked PPCs.

Cross-linked PPCs are continuously conductive.

Abstract

2D conjugated polyphthalocyanines can be obtained as two distinctly different types of material with specific molecular structures and different morphological properties. It was believed that the temperature is the key factor affecting the chemical reaction, but we show that even at the optimal temperature (420{\deg}C), the reaction on vapor/solid interface and liquid/solid interface yields different products: while the former is well-polymerized and ordered, the latter is amorphous and cross-linked with the typical conjugation scale of single PC ring. IR spectroscopy is most sensitive tool for identifying the molecular structure, providing the information on polymerization degree, structural uniformity and content of terminal groups. We show that, unlike the ordered PPCs, the cross-linked product can be reproducibly obtained as continuous conductive material.