Large-scale, ultra-dense and vertically standing zinc phthalocyanine π–π stacks as a hole-transporting layer on an ITO electrode

Abstract

Vertically standing π–π stacks play a key role in advancing the charge transporting properties in the fields of some organic materials and devices such as organic solar cells, organic light-emitting diodes and photodetector. However, realization of large-scale, ultra-dense and vertically standing π–π stacks of organic semiconductors is still a big challenge. By using an amide armed ZnPc–COOH molecule, we show herein a facile solution deposition method to prepare large-scale (>2 × 3 mm²), ultra-dense (completely covering the ITO surface) and vertically standing π–π stacks through supramolecular self-assembly. These vertically standing π–π stacks show a high conductivity and hole mobility, of the order of 10⁻³ S cm⁻¹ and 10⁻³ cm² V⁻¹ s⁻¹, respectively, and act as the hole-transporting layer on the ITO electrode in organic solar cells.