Flexo printed sol-gel derived vanadium oxide films as an interfacial hole-transporting layer for organic solar cells

Abstract

In this paper we report on the synthesis and development of vanadium oxide precursor flexographic ink for the printing of hole-transporting layers in organic solar cells. For the synthesis of vanadium oxide inks, a sol-gel methodology was utilized. By modifying the vanadium alkoxide precursor with a right type of coordinating ligands a stable and flexoprintable ink has been successfully developed. Flexo-printing afforded smooth and uniform vanadium oxide sol-gel films on top of PCDTBT:PC 70 BM films. The conversion of the synthesized sol-gel film into a corresponding vanadium oxide layer was followed by DSC/TGA and XPS analyses. The inks were used for the fabrication of inverted organic solar cells by flexo-printing. Power conversion efficiencies ranging between 3.5 % and 4.5 % were achieved, which are slightly lower than the reference cells using vacuum-deposited MoO 3 as the hole-transporting layers.

Recent Developments in Upscalable Printing Techniques for Perovskite Solar Cells

“…Flexographic printing techniques have been widely used to print the transparent electrodes and interfacial layer to fabricate polymer and organic solar cells. [ 169–173 ] The potential of flexographic printing is that it can print with a high speed of 25 m min ‐1 , which has proven best for preparing front grid Ag electrodes for polymer solar cells. [ 174 ] However, the fastest speed of the flexographic printing resulted in the irregular topology of the Ag electrode (Figure 6b), which consequently led to shunts in the solar cells and reduced the device (area of 6 cm 2 ) performance to less than 2% (Figure 6c).…”

Stability enhancement in organic solar cells by incorporating V2O5nanoparticles in the hole transport layer

“…Vacuum deposited processes had been widely used to deposit V 2 O 5 in the past 22 but these processes are not compatible with the large scale production on account of their high manufacturing costs which lead to a substantial addition in the overall fabrication cost of the device. 23 In recent years, efforts have been made to solution deposit the V 2 O 5 by using different techniques such as brush painting, 24 solution processed spin coating, 11 sol-gel derived vanadium oxide, 20,25 and several other methods discussed in ref. 15-21. However, still a lot of work is needed to be done to nd the best and cheaper ways to deposit these oxides, for optimizing the material properties to get the highly efficient devices compatible with PEDOT:PSS and exhibiting high stability.…”

Solution‐Processable Anode Double Buffer Layers for Inverted Polymer Solar Cells

“…A number of different materials have been used on the laboratory scale as alternatives to e‐MoO x and PEDOT:PSS also in soluble (in principle, printable) form. For instance, vanadium oxide (VO x ) is obtained from widely available alcoholates precursors and can be deposited with continuous printing techniques …”