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.