Identifying the relationships between subsurface absorber defects and the characteristics of kesterite solar cells

Understanding the defect characteristics that occur near space-charge regions (SCRs) of kesterite (CZTSSe) solar cells is important because recombination loss at CZTSSe/CdS interface considered main cause their low efficiency. CZTSSe surfaces with different elemental compositions were formed without polishing (C00) and for 20 s (C20) 60 (C60). For C60, a specific region SCR was excessively Cu-rich Zn-poor compared to C00 C20. Various charged defects where variation large. As deep acceptor energy level (Ea2) increased, efficiency, open-circuit voltage deficit, current density degraded, this phenomenon especially rapid large Ea2 values. became deep, carrier diffusion length decreased more mobility than CuInGaSe2 (CIGSe) cells. The amplitude electrostatic potential fluctuation in induced high short lifetime. Consequently, properties strongly degraded by levels those CIGSe