Hysteresis Analysis of Hole-Transport-Material-Free Monolithic Perovskite Solar Cells with Carbon Counter Electrode by Current Density–Voltage and Impedance Spectra Measurements

Abstract

Due to the tremendous increase in power conversion efficiency (PCE) of organic–inorganic perovskite solar cells (PSCs), this technology has attracted much attention. Despite being the fastest-growing photovoltaic technology to date, bottlenecks such as current density–voltage (J–V) hysteresis have significantly limited further development. Current density measurements performed with different sweep scan speeds exhibit hysteresis and the photovoltaic parameters extracted from the current density–voltage measurements for both scan directions become questionable. A current density–voltage measurement protocol needs to be established which can be used to achieve reproducible results and to compare devices made in different laboratories. In this work, we report a hysteresis analysis of a hole-transport-material-free (HTM-free) carbon-counter-electrode-based PSC conducted by current density–voltage and impedance spectra measurements. The effect of sweep scan direction and time delay was examined on the J–V characteristics of the device. The hysteresis was observed to be strongly sweep scan direction and time delay dependent and decreased as the delay increased. The J–V analysis conducted in the reverse sweep scan direction at a lower sweep time delay of 0.2 s revealed very large increases in the short circuit current density and the power conversion efficiency of 57.7% and 56.1%, respectively, compared with the values obtained during the forward scan under the same conditions. Impedance spectroscopy (IS) investigations were carried out and the effects of sweep scan speed, time delay, and frequency were analyzed. The hysteresis was observed to be strongly sweep scan direction, sweep time delay, and frequency dependent. The correlation between J–V and IS data is provided. The wealth of photovoltaic and impendence spectroscopic data reported in this work on the hysteresis study of the HTM-free PSC may help in establishing a current density–voltage measurement protocol, identifying components and interfaces causing the hysteresis, and modeling of PSCs, eventually benefiting device performance and long-term stability.

Recent Criterion on Stability Enhancement of Perovskite Solar Cells

“…The absolute reason behind this incidence is still unacquainted to the researchers. Therefore, hysteresis is an anomalous behavior of a solar cell that is related to the contradiction in the standard J-V curves of the device and is defined by the difference in open circuit voltages (∆V oc ) while applying external dichotomous forward and reverse biases across it to evaluate its PV performance [127,128]. This labyrinth of a PSC device significantly affects its overall performance as well as imparts a negative influence on its long-term stability [129][130][131].…”

“…Later on, Zhang et al [80] reported an HTL-free device based on SrCl 2 -modified CH 3 NH 3 PbI 3 perovskite sensitizer that approached up to 16% PCE with enhanced stability. Other than these precedents, many more researchers have reported HTL-free device structures that exhibited comparatively better stability than HTL-comprising devices [127,135,214,[278][279][280][281][282]. Another advantageous aspect of these devices is their low-cost fabrication process since one of the basic layers is eliminated in such construction.…”

Configuration of Methylammonium Lead Iodide Perovskite Solar Cell and its Effect on the Device's Performance: A Review

“…They found that the dominant phenomena contributing to hysteresis are trapping/detrapping and capacitive currents. [ 346 ] Recently, Zhang et al. introduced dipole interlayers, including 4‐Fluorophenylacetic acid (FA), 4‐(Trifluoromethyl) phenylacetic acid (TFA), and 3,5‐Bis(trifluoromethyl) phenylacetic acid (2TFA), between ITO and MAPbI 3 perovskite to optimize energy level alignment and reduce defect states at the ITO/MAPbI 3 interface.…”

Application of MXenes in Perovskite Solar Cells: A Short Review

“…Among all these emerging PV technologies, PSCs are the most viable alternate offering a comparable PCE to the mature silicon solar cells. In addition, their lower cost, adjustable bandgap, low-temperature solution processability, lower exciton binding energy, high light absorption coefficients, long charge carrier diffusion lengths, multiple options of performance enhancement and significantly simpler mass production techniques bring in added advantages that conventional Si based technologies lack [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Furthermore, unlike conventional Si solar cells, PSCs also have high performance in diffused or dim lights, making them ideal for indoor applications [ 11 ].…”