Patent ID: 7897416

Claim:
A method of electroplating a stacked layer of a plurality of films in a plurality of sequentially disposed electroplating units onto a continuously moving roll-to-roll sheet to manufacture solar cells, the method comprising the steps of: continuously moving the roll-to-roll sheet through each of the plurality of sequentially disposed electroplating units so that continuous portions of a top surface of the roll-to-roll sheet are positioned for electroplating to occur thereover when disposed in each of the electroplating units; continuously electroplating each one of the films over the top surface of the roll-to-roll sheet using each of the electroplating units as the roll-to-roll sheet moves therethrough, wherein the roll-to-roll sheet includes Cu, In and Ga elements; detecting a thickness of at least one of the films electroplated over a portion of the roll-to-roll sheet and generating a thickness signal corresponding thereto; wherein the step of continuously electroplating includes at least one of adjusting the thickness of each of the films toward a predetermined thickness value for that film using the thickness signal for that film for a subsequent portion of the roll-to-roll sheet that follows the portion of the roll-to-roll sheet, and after the step of detecting, tuning the plurality of films based on the amount of each of the elements deposited so that the stacked layer of the plurality of films has a predetermined molar ratio range of the elements; applying Se to at least one of the plurality of films; reacting the plurality of films within a particular portion of the roll-to-roll sheet and the Cu, In and Ga elements therein with Se to form a Cu(In,Ga)Se 2 absorber layer after completion of the steps of continuously moving, continuously electroplating, detecting and applying for the particular portion of the roll-to-roll sheet; and forming a transparent layer, including a CdS film and a ZnO film, on the Cu(In,Ga)Se 2 absorber layer associated with the particular portion of the roll-to-roll sheet, thereby obtaining at least one solar cell disposed within the particular portion of the roll-to-roll sheet.