Patent ID: 7923281

Claim:
A method of depositing a buffer layer material from a solution to an exposed surface of a solar cell absorber layer disposed on a continuous flexible workpiece for manufacturing solar cells as the continuous flexible workpiece is advanced through a roll-to-roll system, comprising: advancing a section of the continuous flexible workpiece from a supply roll and having a flat shape onto a heated plate including a cavity area, wherein the cavity area of the heated plate is configured to elastically alter the section of the continuous flexible workpiece into a curved shape that conforms to the cavity area of the continuous flexible workpiece; flowing a supply solution over an exposed surface of the solar cell absorber layer of the curved-shape section of the continuous flexible workpiece, wherein the supply solution is maintained at a first temperature before flowing into the section of the continuous flexible workpiece that conforms to the cavity area of the heated plate with the curved shape and wherein the supply solution includes all the chemical components of the buffer layer material; heating, to a second temperature which is higher than the first temperature, the continuous flexible workpiece and the solar cell absorber layer using the heated plate when the section of the continuous flexible workpiece is within the cavity area and conforming to the cavity area with the curved shape, wherein the heating of the continuous flexible workpiece and the absorber layer cause the transfer of heat from the solar cell absorber layer to at least a portion of the solution that is in contact with the exposed surface of the solar cell absorber layer and to cause depositing of the buffer layer material within the solution onto the exposed surface of the solar cell absorber layer; and moving the section of the continuous flexible workpiece away from the cavity areas of the heated plate so that the section of the continuous flexible workpiece flattens.