Electronic-Ionic Transport in MAPbBr₃ Single Crystal: The Evidence of Super-Linear Power Law in AC Conductivity

Abstract

Hybrid halide perovskites recently emerged as promising semiconductor materials for high-mobility field-effect transistors and detectors due to their unique optoelectronic properties. However, iontronics in these materials play a significant role in charge carrier dynamics. In addition, the impact of grain boundaries and trap density on the dielectric properties and the alternate current (AC) ionic conductivity has been one of the most debated topics. In this work, we have studied the electro-ionic dynamics in perovskite single crystals (SCs) using temperature-dependent impedance spectroscopy and the transient photovoltage (TPV) technique. The device capacitances are temperature-independent, revealing that the temperature is only accelerating the migration of ions (MA+ and Br–) but not increasing the number of ion migrations in single crystals. Moreover, the ions in perovskite single crystals are not trapped at the grain boundaries, and hence all of the ions participate in the conduction; this leads to a higher increase in conductivity resulting in the super-linear power law (SPL) region at a higher frequency. Furthermore, TPV measurements also confirmed the temperature independence recombination lifetime in these materials. The maximum values of responsivity (R), detectivity (D), and external quantum efficiency (EQE) are 12.35 mA/W, 5.89 × 109 Jones, and 38.8%, respectively. This work will be beneficial for understanding charge carrier dynamics in single-crystal field-effect transistors (FETs) and detectors.

Tuning Conductivity of Lead-Free Cs2AgBiBr6 Double Perovskite Ternary Composite with PEDOT:PSS and Carbon Black for Supercapacitor Application

“…The high-frequency semicircle can be attributed to the charge transfer resistance ( R ct ), while the low-frequency arch is related to ion transport, ion interactions, and redox reactions at the perovskite/electrolyte interface. The equivalent series resistance (ESR), which represents the contact resistance at the perovskite active materials and the liquid electrolyte interface, can be inferred from the real impedance ( x -axis) intercept on the left side of the high-frequency semicircle . The ESR values of the electrodes were negligible for C-15 and C7-P7 and 50.3 Ω for the P-15 composite, indicating that the carbon-based supercapacitors exhibited fast charging/discharging response times.…”

“…The equivalent series resistance (ESR), which represents the contact resistance at the perovskite active materials and the liquid electrolyte interface, can be inferred from the real impedance (x-axis) intercept on the left side of the high-frequency semicircle. 33 The ESR values of the electrodes were negligible for C-15 and C7-P7 and 50.3 Ω for the P-15 composite, indicating that the carbon-based supercapacitors exhibited fast charging/discharging response times. The values of R ct for C-15, P-15, and C7-P7 electrodes were found to be approximately 177.09, 88.3, and 117.7 Ω, respectively.…”

Photo‐generated Charge Trapping in Phase Segregated Halide Perovskites – A Comprehensive Approach towards Efficient Photo‐Rechargeable Ion Capacitors

“…In last decades organic‐inorganic hybrid halide perovskite materials have been utilized for photovoltaics [15–17] and other optoelectronic applications [18–20] due to extraordinary properties. These materials have shown great promise for the fabrication of efficient energy storage devices for smart applications [21–26] .…”

Iontronics in Hybrid Halide Perovskites for Smart Portable Electronic Devices and Their Challenges

“…Metal halide perovskites (MHPs) structured as ABX 3 compounds, where A represents an organic or inorganic cation, B is a metal cation (typically lead or tin), and X is a halide anion, have achieved remarkable attention in the field of solar photovoltaics − owing to their extraordinary optoelectronic properties of high absorption coefficient, large carrier diffusion length, , high carrier mobility, , ambipolar charge transport, tunable band gap, , long carrier lifetime, , and low-cost solution based processability. , The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has skyrocketed to the latest record of 25.7%, advancing to the top values accomplished by single crystalline silicon solar cells . As a result of considerable interdisciplinary research worldwide from the society of researchers with varied backgrounds, the applications of MHPs have expanded beyond solar cells to numerous other optoelectronic devices such as light emitting diodes, − photoelectrochemical cells for water splitting and CO 2 reduction, , memory devices, , supercapacitors, − X-ray detectors, and photodetectors . Notably, such multiple functions and the versatility of these materials have led to explorations beyond terrestrial applications, with ongoing investigations into the potential use of perovskite solar cells in space conducted by researchers at NREL.…”

“…(b) Iontronics in single crystals and polycrystalline thin films through deep and shallow traps. Reprinted with permission from ref . Copyright 2022, American Chemical Society.…”