Peeling Technique by Two-Dimensional MoSe2 Atomic Layer for Bifacial-Flexible Cu(In, Ga)Se2 solar cells

MoSe
2
atomic layer is applied for the lift-off process to fabricate light-weight and bifacial flexible Cu(In, Ga)Se2 (CIGSe) solar cells. The results show that CIGSe solar cells are successfully peeled from a Mo rear contact when the c-axis of the MoSe
2
, formed between the Mo and CIGSe layers, is vertically oriented to the Mo surface. 11.5% efficient flexible cells are fabricated, indicating a high-performance ratio of 95.0% compared with the 12.1% efficient substrate cells, suggesting the usefulness of layered-grown MoSe
2
for the lift-off technique. Finally, by applying the lift-off process, light-weight and bifacial flexible CIGSe solar cells utilizing thin Au and ITO back contacts are derived.