[20p-E314-1~14] 16.3 Bulk, thin-film and other silicon-based solar cells

[20p-E314-12] Improvement of Characteristics of Amorphous Si Quintuple-Junction Solar Cells under Low Illuminance

〇Makoto Konagai¹, Ryo Sasaki¹, Momoka Yonemura¹, Ryousuke Ishikawa¹ (1.Tokyo City Univ.)

Keywords:solar cell, amorphous Si solar cell, multi-junction

Quintuple-junction solar cells which consist of a-SiO_x:H/a-SiO_x:H/a-Si:H/a-SiO_x:H/ a-SiO_x:H were fabricated by plasma CVD method. The total thickness was 0.6-0.8 mm. A very high open circuit voltage of 3.5 V was demonstrated under LED light illumination. Irradiation intensity dependence of V_oc of quintuple -junction solar cells was measured. The decreasing amount DV_{oc (1/10)} of the open circuit voltage when the irradiation intensity became 1/10 was 62mV/cell. Voc drops rapidly from around the irradiation intensity of 1mW/cm². This large Voc reduction is due to leakage current. Then, we discussed the origin of the leakage current, and finally by improving the leakage current, a very high open circuit voltage V_oc of 3.0 V was obtained at 200 lux.