Multidoped CsSnI3 as light absorber in perovskite solar cell delivering 17 % efficiency

Lead-free perovskite CsSnI3, comprised of inorganic cations, emerges as an appealing absorber material for perovskite solar cells. In such cells, the absorbers are either intrinsic or mono-doped, functioning as n-type or p-type semiconductors. This study adopts a novel approach aimed at enhancing charge transportation by exploring a multi-doped absorber comprising both n-doped CsSnI3 and p-doped CsSnI3. Two PSCs, labeled as D1 (ITO/TiO2/CsSnI3/NiO/Au) and D2 (ITO/TiO2/n-CsSnI3/p-CsSnI3/NiO/Au), are thoroughly analyzed and compared in terms of figure of merit using the SCAPS-1D framework. This study reveals an increase in power conversion efficiency from 3.09 % to 4.09 %, fill factor from 47.1 % to 53.2 %, short-circuit current from 18 mAcm(-2) to 18.84 mAcm(-2), and open-circuit voltage from 0.364 V to 0.408 V in D2 compared to D1, attributed to multidoping of the absorber. Furthermore, 63 different combinations of electron and hole transport materials are explored within D2, aiming to optimize the device's performance. In addition, analysis of impact of both doping and interface defect density on the figure of merit of D2 is assessed. The combination of BaSnO3 with Cu2O as charge transport materials in D2 enables the device to achieve a power conversion efficiency of 17 %, fill factor of 73.6 %, short-circuit current 28.63 mAcm(-2), and open-circuit voltage 0.802 V when the perovskite bulk defect density is <= 10(15) cm(-3) and perovskite/charge transport interface defect is 10(15) cm(-2). The findings of this study provide valuable insights for the development of highly efficient solar cell.