Impact of Interface Energy Alignment on the Dynamic Current–Voltage Response of Perovskite Solar Cells

Abstract

The mismatch of the energy level between the electron transport layer (ETL) and the perovskite (PS) film is one of the origins of current−voltage (J−V) hysteresis in perovskite solar cells (PSCs). Drift-diffusion simulations are conducted to explain how the band alignment affects the charge extraction across the ETL/PS interface, and hence varies the responses of photocurrent. Our simulations show that the band alignment has a profound influence on the evolution of the profiles of movable ions during voltage scan. The band mismatch at the ETL/PS interface is shown to engender the accumulation of movable anions and give rise to severe J−V hysteresis. We further demonstrate that a rational design on the energy alignment of PSCs is vital to reduce the hysteresis no matter if charge loss in PSCs is determined by bulk recombination or trap-assisted surface recombination. Moreover, the PSCs suffering from interface band mismatch are found to exhibit various hysteresis behaviors depending on the rate of voltage scan. It implies that the voltage scan at different speeds could be helpful to diagnose the problem of PSCs.

An efficient approach for controlling the crystallization, strain, and defects of the perovskite film in hybrid perovskite solar cells through antisolvent engineering

“…S10a and b † revealed a decrease in the VBM by 0.23 eV from −5.45 eV (reference) to −5.68 eV (OABr), which in practice, would favor the transport of charge carriers to the HTL due to an optimum energy level offset of about 0.28 eV between the VBM of the perovskite and the HOMO of PTAA. 64,65 The XPS measurements of the VB region presented in Fig. S10c † show that the VBM is located at −1.2 eV below the Fermi level or at −5.4 eV with respect to the vacuum level, in excellent agreement with the APS measurements.…”

Chemical approaches for electronic doping in photovoltaic materials beyond crystalline silicon

“…The band mismatch and defect states at the perovskite/ transport interfaces would cause carrier accumulation and undesired nonradiative recombination, which damaged the long-term stability of the device, especially for MPP tracking. [419][420][421] The Lewis acid-base theory is widely adopted for chemical passivation and doping in perovskite surface. Lewis base-based deep traps, such as the undercoordinated I and antisite PbI 3 À can be eliminated by the Lewis acid, such as C60 and its derivatives (PCBM, ICBA, etc.)…”

Influence of Ion Vacancy Migration on Short‐Circuit Current of Perovskite Solar Cells

“…In recent years, many publications focus on the topic of ion vacancy migration in the field of perovskite solar cells (PSCs). [1][2][3][4][5][6] Ion vacancy motion in perovskite causes the redistribution of trap states, [7,8] the degradation of perovskite, [9,10] and the J-V hysteresis. [11][12][13][14][15][16][17][18][19] Snaith, Richardson, Courtier, Calado et al [11][12][13][14][15][16][17][18][19] simulated the J-V hysteresis by solving the driftdiffusion equation coupled to Poisson's equation.…”