Additive engineering for stable halide perovskite solar cells

Halide perovskite solar cells(PSCs)have already demonstrated power conversion efficiencies above 25%,which makes them one of the most attractive photovoltaic technologies.However,one of the main bottlenecks towards their commercialization is their long-term stability,which should exceed the 20-year mark.Additive engineering is an effective pathway for the enhancement of device lifetime.Additives applied as organic or inorganic compounds,improve crystal grain growth enhancing power conversion efficiency.The interaction of their functional groups with the halide perovskite(HP)absorber,as well as with the transport layers,results in defect passivation and ion immobilization improving device performance and stability.In this review,we briefly summarize the different types of additives recently applied in PSC to enhance not only efficiency but also long-term stability.We discuss the different mechanism behind additive engineering and the role of the functional groups of these additives for defect passivation.Special emphasis is given to their effect on the stability of PSCs under environmental conditions such as humidity,atmosphere,light irradiation(UV,visible)or heat,taking into account the recently reported ISOS protocols.We also discuss the relation between deep-defect passivation,non-radiative recombination and device efficiency,as well as the possible relation between shallow-defect passivation,ion immobilization and device operational stability.Finally,insights into the challenge and criteria for additive selection are provided for the further stability enhancement of PSCs.

Optimization of Mo/Cu(In,Ga)Se2/CdS/ZnO Hetero-Junction Solar Cell Performance by Numerical Simulation with SCAPS-1D

The paper presents a one-dimensional simulation study of chalcopyrite Cu(In,Ga)Se2(CIGS)solar cells,where the effects of the variation of CIGS,CdS,and ZnO layers are presented.Additionlly the influence of the variation of doping and the defects density of shallow uniform donors and acceptors types are also presented.The analyse of the simulation results shows that recombination inside the space charge region(SCR)decrease more our CIGS solar cell model performance.We also found that the electrical parameters increase with increasing CIGS absorber doping density exception of JSC values that reach their maximum at 1016cm-3 and decrease due to recombination of charge carriers in the p-n junction particularly the recombination inside the SCR.We also stressed the fact that the effects of shallow uniforme donor density is very low on the performance of our CIGS solar cell model is important because it will allow to control the width of space charge region from shallow uniform acceptors defect density that has a strong influence on the different electrical parameters.Yet,good optimization of performance of the CIGS-based solar cell necessarily passes though a good control of the space charge region width and will constitute a boosting perspective for the preparation of our next paper.We contact that the results obtained of the numerical simulation with SCAPS-1D show a good agreement comparatively of the literature results.The simulation of our CIGS solar cell presents best performances if the values of the absorber layer thickness is in the range of 0.02 to 0.03μm,the buffer layer thickness is in the range of 0.02 to 0.06μm and the defects density of shallow uniform acceptors types is in the range of 1015 to 1017cm-3.