  Metal halide perovskites possess many physical properties amenable to
optoelectronic applications, whereas the realization of these potentials has
been hampered by their environmental and electronic instabilities. The
morphological and molecular low dimensional perovskites and perovskite related
materials have shown much promise in enhancing the chemical stability due to
their unique molecular structures. Here we report on robust and reproducible
four-terminal (4T) electrical measurements in a one-dimensional (1D) organic
metal halide hybrid, (R)-{\alpha}-methylbenzylammonium lead triiodide
((R-{\alpha}-MBA)PbI3) made possible by its chemical stability. The results
reveal a distinct intrinsic ion migration dynamic of single exponential, which
underlies the unique 4T I-V characteristics. The dynamic is directly verified
by real-time measurements of the transient ionic current. Our observations are
consistent with photo-activation and field-assisted ion migration. The
elucidated intrinsic ion dynamics may provide the physical basis for
understanding and modelling the ubiquitous hysteresis in metal halides based
electronic devices and new insights into the dynamics of ion migration in metal
halide perovskites and hybrids in general.
