Role of BCP layer on nonlinear properties of perovskite solar cell

Organic-inorganic hybrid halide perovskite materials have been most attractive for wide range of optoelectronic applications. Investigating the photo-response in these devices will be very useful to understanding cell performance in different conditions and applications. For understanding non-linearity photo-response we use the Bathocuproine (BCP) as blocking layer in two interfaces of inverted perovskite solar cell (FTO/NiO/BCP/Perovskite/PCBM/Au and FTO/NiO/Perovskite/PCBM/BCP/Au). Employing thick BCP layer (≈15 nm) caused s-shaped JV curve due to charge accumulation at interfaces. The nonlinearity effect was also explored for devices with s-shaped JV and established that device parameters respect to light intensity were nonlinear. Short circuit current had a nonlinear response respect to light intensity while the voltage behavior in terms of light intensity indicated that monomolecular recombination is dominant mechanism. The open circuit voltage is almost 100% nonlinear from 1 to 0.1 sun in device A, while in second device shown from 1 to 0.5 sun almost 50% nonlinearity. The results suggest that our simple strategy not only can be useful for understanding how cell performance is but also can be used in some optical setup such as Focus induced photo-response (FIP).