Performance analysis & optimization of inverted inorganic CsGeI3 perovskite cells with carbon/copper charge transport materials using SCAPS‑1D

Hybrid perovskite solar cells (PSC) have achieved efficiencies (PCE) of
more than 25%. However, the organic compound is causing structural
degradation due to heat and moisture. This has led to the exploration of
inorganic perovskites. Inorganic-PSC such as cesium has seen a
breakthrough by achieving highly stable PSC with PCE exceeding 15%. In
this work, the inorganic non-toxic PSC of cesium germanium tri-iodide
(CsGeI3) is numerically modeled in SCAPS-1D with two carbon-based and two
copper-based charge transport layers(CTL). This study introduces in-depth
modelling and analysis of CsGeI3 through continuity and Poisson equations.
Cu-CTL are selected to increase the electric conductivity of the cell,
while carbon-CTL is used to increase the thermal conductivity. Four
structures are designed and presented. A systematic approach is adopted to
obtain the optimized design parameters for maximum performance. From the
results it is observed that the C60/CsGeI3/CuSCN structure has the highest
performance, with open-circuit voltage of 1.0169V, short-circuit current
of 19.653 mA/Cm2, fill factor of 88.13% and PCE of 17.61%. Moreover, the
effect of quantum efficiency, electric field, interface recombination,
interface defects, layer thickness, defect density, doping concentration,
working temperature and reflection coating on the cell performance are
studied in detail.