Influences of dielectric constant and scan rate on hysteresis effect in perovskite solar cell with simulation and experimental analyses

Abstract

In this work, perovskite solar cells (PSCs) with different transport layers were fabricated to understand the hysteresis phenomenon under a series of scan rates. The experimental results show that the hysteresis phenomenon would be affected by the dielectric constant of transport layers and scan rate significantly. To explain this, a modified Poisson and drift-diffusion solver coupled with a fully time-dependent ion migration model is developed to analyze how the ion migration affects the performance and hysteresis of PSCs. The modeling results show that the most crucial factor in the hysteresis behavior is the built-in electric field of the perovskite. The non-linear hysteresis curves are demonstrated under different scan rates, and the mechanism of the hysteresis behavior is explained. Additionally, other factors contributing to the degree of hysteresis are determined to be the degree of degradation in the perovskite material, the quality of the perovskite crystal, and the materials of the transport layer, which corresponds to the total ion density, carrier lifetime of perovskite, and the dielectric constant of the transport layer, respectively. Finally, it was found that the dielectric constant of the transport layer is a key factor affecting hysteresis in perovskite solar cells.

Hysteresis and Its Correlation to Ionic Defects in Perovskite Solar Cells

“…This dynamic and thermally activated effect originates from a delayed current response of the device with respect to a change in the external voltage. , Several mechanisms have been proposed as the reasons for hysteresis in perovskites, such as charge carrier trapping and detrapping, , ion migration, , ferroelectric polarization, , and capacitive effects. , It is widely acknowledged that the accumulation of defects at the perovskite/transport layer interface causes hysteresis by influencing the electric field distribution within the device. Several theoretical and experimental studies deduced the relevant time scales related to the migration of defect species in perovskites via quantifying hysteresis as a function of temperature and sweep rate of a J – V measurement. ,− However, the origin of the ionic defects is still under debate.…”

A study of the optical properties of wide bandgap oxides for a transparent photovoltaics platform

“…Moreover, the dielectric constant value ( ε r ) reflects the degree of polarization in the material, indicating that a higher ε r value corresponds to a lower electric field and vice versa . 27 Two spectral regions primarily concern TPV applications. The first is the static dielectric constant, which defines polarization under a constant electric field.…”

Influence of interfacial recombination on hysteresis in the J-V curves of TiO2/MAPbI3/Spiro-OMeTAD solar cells

“…Van Reenen et al and Richardson et al added ion migration into the drift diffusion model to explain the hysteresis phenomenon [20,31]. At present, many researches have also demonstrated that ion migration is the key factor leading to the hysteresis effect, and the joint action of ion migration and carrier recombination causes the hysteresis phenomenon [20,[31][32][33][34]. Furhermore, some factors affecting the hysteresis characteristics of J-V curve have been reported: the material and interface quality of perovskite layer [35][36][37], the use of different transport layer materials [38][39][40][41][42], scanning rate and bias voltage of J-V test [34,43,44].…”

“…At present, many researches have also demonstrated that ion migration is the key factor leading to the hysteresis effect, and the joint action of ion migration and carrier recombination causes the hysteresis phenomenon [20,[31][32][33][34]. Furhermore, some factors affecting the hysteresis characteristics of J-V curve have been reported: the material and interface quality of perovskite layer [35][36][37], the use of different transport layer materials [38][39][40][41][42], scanning rate and bias voltage of J-V test [34,43,44]. The passivation of perovskite/transport layer interfaces has been proved to suppress the hysteresis of PSCs experimentally [36,45,46].…”