Odd rectification, hysteresis and quasi switching in solid state devices based on mixed ionic electronic conductors

The Nature of Ion Conduction in Methylammonium Lead Iodide: A Multimethod Approach

“…[12,13] This situation can be expected to take place in all perovskite solar cell devices due to the ion-blocking nature of the neighboring phases. [14] In addition to this phenomenon, which comprises the entire bulk, space charge polarization occurs at the interface between perovskite and neighboring phases but on ac ompletely different length scale (for generalized treatments the reader is referred to literature [15,16] ). Mobile ionic point defects are of great significance for such space charge potentials at the contacts,b et hey present already in equilibrium or generated under load, [17] and hence they are important for electronic carrier extraction and thus for device performance.…”

Negative differential resistance and hysteresis in Au/MoO3−δ/Au devices

“…1), the displacement current cannot be neglected due to charging of the metal electrodes, and the current does not pass through the origin. 20,29 In the calculated I-V relations, tted to the measured I-V relations in Fig. 1, the curves do not self-cross.…”

“…Owing to a difference in the response of ions and electrons to an applied voltage, hysteresis appears. 29,30 Strong negative differential resistance develops, and the I-V curves do not cross. For even lower frequency, the hysteresis is signicantly reduced, as shown in Fig.…”

“…The electrons are driven by the applied voltage, whereas the ions are driven by a combination of the applied voltage V and a difference in the Nernst voltage, V th , which equals (up to a coefficient being the ion charge) to a difference, on the oxide, in the chemical potential of the chemical components from which the ions are derived. 29,37 Thus, for oxygen ions, the latter is a difference in the chemical potential of atomic oxygen (for neutral oxygen vacancies, it is minus that value). For a uniform surrounding, V th can still appear as it is generated by polarization within the oxide under an applied voltage when the electrodes exhibit poor material transfer.…”

“…Eventually, the ion distribution is changed to the long-term distribution, being depleted on the side which is under positive polarity. 29 This leads to a corresponding depletion of electrons there, which increases the overall resistance and decreases the current, i.e., NDR appears. Signicant hysteresis appears in the frequency range of 2 Â 10 À4 to 2 Â 10 À2 Hz for the amplitude of 0.6 V at 70 C. This provides an estimate of the relaxation time of the hysteresis in the range of 50-5000 s, typically 500 s.…”