Influence Of Mobile Ions Research Articles

Pulsed operation of perovskite LEDs: a study on the role of mobile ions

ABSTRACT Metal halide perovskite light-emitting diodes (PeLEDs) are a promising technology for energy-efficient and cost-effective lighting and displays, thanks to their tunable color emission, high brightness, color purity and low-temperature fabrication. However, the mixed ionic-electronic conductivity of perovskite materials presents unique challenges, as ionic defects can redistribute under operation, affecting the energy landscape and charge recombination mechanisms. Our drift-diffusion simulations establish a connection between the transient electroluminescence (TrEL) signals of PeLEDs under pulsed operation and the influence of mobile ions. We find that the TrEL plateau value’s dependence on the duty cycle and end-of-pulse overshoot can be explained by the time-varying distribution of ionic defects. The inclusion of mobile ions is crucial to understand the TrEL response. Moreover, the simulations highlight injection barriers at the perovskite/charge-transport layer interfaces, such as is the case for the hole transport layer in our example, as a significant source of non-radiative charge recombination. These findings contribute to the understanding of transient ionic processes in perovskite-based devices.

Influence of mobile ions on the electroluminescence characteristics of methylammonium lead iodide perovskite diodes

Upon forward biasing the perovskite diodes, the turn-on voltage of the electroluminescence diminishes and its intensity substantially increases, suggesting that mobile ions do play an important role in device operation.

Electrode polarization and interface effects in liquid crystal systems with mobile ions: development of a model of bipolar diffusion

Abstract The influence of mobile ions on the results of impedance spectroscopy (dielectric spectroscopy) measurements performed on a liquid crystal cell using the new mathematical model recently described was investigated. This mathematical model reformulates the fundamental equation system of continuity for mobile charge carriers and the Poisson equation using new variables. One makes the following assumptions: ions have different mobilities and diffusion coefficients, there is no generation-recombination process, the equilibrium carrier concentrations are uniform and equal each other, the electrodes are either completely blocking or blocked with adsorption-desorption processes. The final result is the analytical expression of the equivalent admittance for the system, allowing to have a clearer picture of the mobile ions and of the processes that occur at the electrode interface influencing the dielectric behavior.

Influence of mobile ions on the electronic conduction in silicon oxide films

The voltage-current characteristics of capacitors with an evaporated SiO dielectric containing a high ion concentration have been investigated. It is shown that the influence of the space charge effect caused by mobile ions on the potential distribution and hence on the electron current is easily described by an effective electric field, which is proportional to the applied voltage across the capacitor.