From Frequency Domain to Time Transient Methods for Halide Perovskite Solar Cells: The Connections of IMPS, IMVS, TPC, and TPV

Abstract

The correlation of different methods of measurement can become an important tool to identify the dominant physical elements that govern the electronic and ionic dynamics in perovskite solar cells. The diverse phenomena underlying the response of halide perovskite materials to different stimuli are reflected in time-domain measurements, where transients appear with time scales spanning orders of magnitude, from nanoseconds to hours. We discuss the connection between different frequency- and time-domain methods to probe the voltage and current response of halide perovskite solar cells to different small perturbations. To solve the frequency-to-time transformation, we start from models of the transfer function of intensity-modulated photocurrent spectroscopy (IMPS) and derive the associated impulse response function, the transient photocurrent (TPC), in response to a short light pulse. Similarly, we determine the transient photovoltage (TPV) starting from the intensity-modulated photovoltage spectroscopy (IMVS) transfer function. We also discuss the open-circuit voltage decays (OCVD). We first show the response of simple equivalent circuit models, and then we treat the full model for generation–diffusion–recombination of electrons that shows a spiraling loop in IMPS. This model gives rise to overshoots in the time domain.

Impedance Spectroscopy of Metal Halide Perovskite Solar Cells from the Perspective of Equivalent Circuits

“…The connection between the techniques is explained in ref ; see Figure for the different measurement conditions applied to a simple EC. Impedance Z (ω) is defined in the absence of modulated illumination, Ĵ Φ = 0.…”

“…Note that the current source and parallel resistance can be transformed to a voltage source and series resistance. Reproduced from ref . Copyright 2020 American Chemical Society.…”

“…Recently, it has been remarked that the IMPS of MHP shows negative features in the real part of Q as it is inferred from Figures and d. , The same result is obtained from drift-diffusion simulations as shown in Figure . These features can be well described by the following model of the IMPS transfer function , that is based on the standard generation–diffusion–recombination approach , In eq , ω rec = τ rec –1 is a recombination frequency, ω d = D n / d 2 is a frequency of diffusion over the cell thickness d , and ω α = D n α 2 is a frequency of diffusion over light absorption distance, α being the optical absorption coefficient.…”

Homogeneous Grain Boundary Passivation in Wide‐Bandgap Perovskite Films Enables Fabrication of Monolithic Perovskite/Organic Tandem Solar Cells with over 21% Efficiency

“…[ 51 ] The charge recombination time increased from 13.3 µs for MA 1.06 PbI 2 Br(SCN) 0.12 based PSCs to 31.3 µs of the MA 0.96 FA 0.1 PbI 2 Br(SCN) 0.12 based champion device (Figure 6c), which further demonstrates the effect of FA + on modifying the perovskite film properties and agrees well the improved FF of the MA 0.96 FA 0.1 PbI 2 Br(SCN) 0.12 based PSCs. Moreover, according to the Laplace transformation, [ 52 ] the carrier recombination lifetime (τ a ) of the R rec C rec circuit in the EIS spectra is calculated to be 54.8 µs and 84.3 µs for the MA 1.06 PbI 2 Br(SCN) 0.12 and MA 0.96 FA 0.1 PbI 2 Br(SCN) 0.12 based PSCs, respectively, which is also consistent with the TPV lifetimes of the corresponding PSCs. [ 53 ] Figure S14 (Supporting Information) shows that the MA 0.96 FA 0.1 PbI 2 Br(SCN) 0.12 based devices also exhibited lower dark current than the MA 1.06 PbI 2 Br(SCN) 0.12 based devices, indicating that the optimized device can more effectively prevent the current leakage, which is in good agreement with the improved J sc and FF of the MA 0.96 FA 0.1 PbI 2 Br(SCN) 0.12 based devices.…”

Recent Progress of Light Intensity‐Modulated Small Perturbation Techniques in Perovskite Solar Cells

“…To get the insights into the physical processes occurring within the PSC, a unique electrical EC is required, which can represent both the EIS and IMPS plots obtained from the same device. [22] Pockett et al for the first time presented EC for the interpretation of IMPS and IMVS techniques of planar PSCs as the transmission line model used for meso-PSCs earlier [23,24] does not work for planar PSCs. [25] The authors proposed EC, as shown in Figure 1a, consisting of total capacitance (C total ), which represents overall charge stored in the device.…”