Validation of Mazhari’s Equivalent Circuit Model for Perovskites Solar Cells With S-Shaped J–V Curves

The appearance of kinks in the fourth quadrant of current–voltage curves decreases dramatically the efficiency of photovoltaic solar cells (SCs). These S-shaped
${J}$
–
${V}$
curves have been successfully reproduced using different lumped-parameter equivalent circuits, composed of two or more diodes. In this work, Mazhari’s three-diode equivalent circuit is used to model the S-shaped
${J}$
–
${V}$
curves of perovskite SCs numerically simulated with Silvaco ATLAS TCAD. The simulated cell structure is fluorine-doped tin oxide (FTO)/TiO2/MAPbI3/ 2,
$2^{\prime}$
,7,
$7^{\prime}$
-tetrakis [N,N-di (4-methoxyphenyl) amino]-9,
$9^{\prime}$
-spirobifluorene (Spiro-OMeTAD)/Au and, in order to reproduce
${J}$
–
${V}$
curves with a kink, perovskite carrier mobility has been decreased below 0.25 cm2/(V
$\cdot $
s) and defect density in the active layer has been increased above
$1\times 10^{{14}}$
cm
$^{-{3}}$
. For each parameter,
${J}$
–
${V}$
curves have been simulated for different AM1.5 irradiation levels, from dark conditions up to 2 suns. For each device, a set of circuital parameters has been obtained independent of irradiation level. The dependence of Mazhari’s circuit parameters on both carrier mobility and defect density will be discussed.