Investigating physical origin of dominant hysteresis phenomenon in perovskite solar cell

Abstract

The progress of perovskite solar cell (PSC) technology is held back due to the presence of anomalous hysteresis in its current–voltage (J–V) characteristics. Understanding the physical origin of J–V hysteresis is crucial for the development of hysteresis-free solar cell. We computationally explore the relative contribution of dominant physical phenomenon that could cause hysteresis in PSC. We explore that accumulation of mobile ions at the interfaces of the cell inside perovskite produces a space charge which in combination with charge trapping/detrapping in deep traps results in hysteresis which is often characterized by an S shaped behavior of J–V curve. We further explore that shallow traps at the interfaces of carrier-extraction layers alone exhibit the combined effects of ion accumulation and deep charge traps, and lead to J–V hysteresis in PSCs. Moreover, we investigate the effect of energy level of deep/shallow traps and show that the energy level of deep/shallow traps plays an important role in J–V characteristics of the cell. Lastly, we explore that high minority carrier lifetime in the bulk of the perovskite mitigates the effects of ion accumulation and/or charge trapping/detrapping and leads to hysteresis-free cell. The results presented in this work are beneficial for the development of hysteresis-free PSCs.