Electrochemical studies on lead iodide

127I and 207Pb Solid-State NMR Spectroscopy and Nuclear Spin Relaxation in PbI2: A Preliminary Study

“…In the higher temperature phases, at least above 540 K, lead atoms have been suggested to dominate the conduction, and at even higher temperatures, electron holes contribute to the conductivity. 34 The hopping among vacancy sites subjects an iodine nucleus to time-dependent electric field gradients. For fast hopping on the NMR time scale, the solid-state NMR spectrum of the iodine nucleus reflects the time-averaged electric field gradient seen by the iodine nucleus.…”

“…2,5 The conductivity of lead iodide has been the subject of numerous investigations. 4,5,10,11,14,16,18,22,28,29,32,34 A study of the temperature dependence of the capacitance and loss tangent 5 indicates the presence of two thermally activated processes affecting its electrical response. The first process, with an activation energy of 0.087 eV (8.4 kJ/mol), is in the range of 288−348 K, and the second process, with a reported activation energy of 0.23 eV (22 kJ/mol), is dominant in the range of 348−393 K. These energies are very much smaller than the ionization energy of 10.45 eV (1.008 MJ/mol).…”

“…Lead iodide (PbI 2 ) has unusual structural properties that result in interesting physical and electronic properties which make this ionic conductor/semiconductor a candidate for use in a variety of applications (see section ). − Despite many published reports using a variety of experimental probes, − the dynamics of the lead and iodine ions at the atomic level are not well understood. Techniques such as X-ray diffraction and neutron scattering provide static information at the atomic level. ,,,,, Techniques such as conductivity measurements ,,,,,,,,,,, give macroscopic information, where the dynamics of atoms can only be described by nonunique models. Although descriptions of atomic motion in this material are model-dependent, 207 Pb and 127 I nuclear magnetic resonance (NMR) experiments can considerably reduce the range of potentially successful models.…”

Electronic conductivity in La1−xBaxF3−x crystals

“…I) also reveal values of ct which are much larger than one. Such a large value of a has been observed many times before and has, amongst others, been ascribed to partial blocking of the ionic current [21,25]. Brook et al [24] have considered a relaxed requirement of complete blocking of ions at the inert interface, in that a residual ionic current Iir is allowed for.…”

Impact of PbI2 Passivation and Grain Size Engineering in CH3NH3PbI3 Solar Absorbers as Revealed by Carrier‐Resolved Photo‐Hall Technique

“…[18,[22][23][24]48] The diffusion lengths are increased by a factor of three with the addition of 5% [27,28] It is important to note that PbI 2 is highly resistive (conductivity around 10 -13 -10 -10 Scm -1 ) and typically exhibits a p-type character. [49,50] Therefore, it is unlikely that the increase in electron density observed upon excess PbI 2 is due to the presence of the secondary phase itself. The improvement of carrier recombination lifetime by one order of magnitude and diffusion length by a factor of three supports the hypothesis of deep trap passivation.…”