Abstract

Hysteresis in perovskite solar cells is a notorious issue limiting its development in stability, reproducibility and efficiency. Ions’ migration coupled with charges’ recombination are indispensable factors to generate the hysteretic curves on the basis of experimental and theoretical calculation studies, however, the underlying physical characteristics are rarely clarified. Here, a mixed electronic-ionic drift-diffusion model combined with bulk and interfacial recombination is investigated. Positive and negative ion species could drift to and accumulate at interfaces between the perovskite/transport layers, influencing internal electric potential profiles and delaying the charges’ ejection to the transport layers. The charges might recombine spontaneously or trap-assisted, reducing the total amount of electrons and holes collected in the external circuit, leading to a diminished photocurrent. Moreover, our calculations indicate that an appropriate measurement protocol is really essential to evaluate the device performance precisely and to suppress J–V hysteresis. Meanwhile, a negligible hysteretic loop could be obtained by balancing the material properties of the transport layers and restraining the ions mobility in the perovskite layer.

Highlights

  • Research enthusiasm on organic–inorganic perovskite solar cells (PSCs) has risen tremendously within the last decade, attributed to their remarkable optoelectronic properties, such as high carrier mobility, suitable band gap and excellent economic efficiency [1]

  • This result indicates that recombination plays a dominant role in the J–V hysteresis phenomenon

  • The results present that the concentration of the ions had no effect on the J–V loops, as seen in Figure 10b, which indicates the potential of large-area PSC panels for commercialization, 4

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Summary

Introduction

Research enthusiasm on organic–inorganic perovskite solar cells (PSCs) has risen tremendously within the last decade, attributed to their remarkable optoelectronic properties, such as high carrier mobility, suitable band gap and excellent economic efficiency [1]. Experimental and theoretical studies indicated that the iodine (I− ) and the methylammonium (MA+ ) are the major available mobile ion species in the perovskite material of methylammonium lead triiodide (MAPbI3 ) [7]. It is these ions’ migration combined with trap-assisted recombination that give rise to the anomalous current density–voltage (J–V) hysteresis [8,9]. It has yet to be clearly clarified what characteristics inside the PSC are modified if the ions could migrate regularly and what functions of the recombination

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