Method and system for depositing thin film on substrate

A method for depositing a plurality of thin films, each having a film thickness less than 10 μm, on a substrate having a first side and a second side, the method comprising:

• immersing the substrate in a precursor liquid by filling a deposition vessel with an amount of the precursor liquid, wherein the deposition vessel has an inlet pipe, an outlet pipe, a drain valve, and a substrate holder configured to suspend the substrate inside the deposition vessel at an immersion depth, wherein the outlet pipe is fluidly connected to the deposition vessel at a first height lower than the immersion depth and the inlet pipe is fluidly connected to the deposition vessel at a second height greater than the outlet pipe, wherein the drain valve is in line with the outlet pipe, and wherein the deposition vessel is filled with the precursor liquid through the inlet pipe;
• draining the precursor liquid by gravity at a controlled flow rate to a collection vessel via the outlet pipe downstream from the drain valve, wherein the collection vessel is configured to receive and contain the precursor liquid from the deposition vessel, wherein a top of the collection vessel is below the outlet pipe of the deposition vessel and wherein the inlet pipe, the outlet pipe, the deposition vessel, and the collection vessel are in fluid communication;
• after the draining, discharging, by gravity, an excess amount of the precursor liquid from the substrate in a precursor vapor atmosphere in the deposition vessel to form a homogenous precursor deposition layer on the first and second sides of the substrate;
• drying the homogenous precursor deposition layer in a drying chamber to form a precursor film on the first and second sides of the substrate;
• removing the precursor film from one of the first side or the second side of the substrate to form a substrate having a single film;
• and
• decomposing the single film on the substrate at a decomposition temperature in a decomposition chamber to form a single thin film of Co3O4 on the substrate;
• repeating the immersing, draining, discharging, drying, removing and decomposing cyclically 8 to 12 cycles to deposit a plurality of further thin film layers upon the single thin film of the Co3O4,
• wherein the single thin film of the Co3O4 is a solar absorber,
• wherein the further thin film layers are CuO, and
• wherein a thickness difference between a thickest part and a thinnest part of each film is less than 500 nm.