Coating or surface treatment method, substrate and apparatus

A coating or surface treatment method comprising the following steps:

• providing a substrate holder and a slot die head, the slot die head having a slit nozzle;
• mounting a substrate on the substrate holder;
• moving the substrate relative to the slit nozzle while supplying a conductive liquid through the slit nozzle onto the substrate such that the conductive liquid is deposited onto the substrate;
• and
• applying an electrical potential difference between the slit nozzle and the substrate using a power source while supplying the conductive liquid through the slit nozzle to the substrate, wherein the power source applies a first potential to the slit nozzle and a second different electrical potential to the substrate.

A coating or surface treatment apparatus comprising,

• a substrate holder for holding a substrate;
• a slot die head comprising a slit nozzle, wherein the slit nozzle and the substrate are configured to move relative to each other;
• the slot die head being configured to supply a conductive liquid through the slit nozzle onto the substrate;
• and
• a power source configured to provide an electrical potential difference, wherein the power source is electrically connected to the slit nozzle and includes an interface for an electrical connection to the substrate, and wherein the power source is configured to provide the electrical potential difference between the slit nozzle and the substrate.