A solar cell incorporates a light harvesting array that comprises: a first substrate comprising a first electrode; and a layer of light harvesting rods electrically coupled to the first electrode, each of the light harvesting rods comprising a polymer of Formula I: X1m. Such a method is useful for producing large quantities of biofilament material. In the method, after arranging an adhesive agent on a mounting region on the wiring board, an electric component is arranged on a mounting region, and the electric component is bonded on the wiring board by thermocompression by using the thermocompression head. The center shaft is pivotally connected with the inner side of the frame, enabling the massage roller device rotate with the center shaft as a pivot. An estimated gain value converted from a result of measuring a resistance value of the head is used as an initial value for the adjustment of the AGC amplifier.