Contact‐Architecture‐Dependent Mixed Ionic‐Electronic Transport in Solution‐Grown MAPbBr 3 Microwire Photodetectors

ABSTRACT Hybrid organic‐inorganic halide perovskites are attractive semiconductors for optoelectronics, but their electrical and photoresponse are often affected by slow ion‐mediated processes. Although ion migration and history‐dependent photoresponse are well established in halide perovskites, how these mixed ionic‐electronic effects depend on device architecture remains unclear. Here, we investigate solution‐grown MAPbBr 3 microwires integrated onto interdigitated Au electrodes in two representative configurations: a single‐gap (SG) device and a multi‐gap (MG) device comprising five parallel electrically active regions. Combining dark and illuminated current‐voltage measurements, SCLC analysis, and time‐resolved photocurrent measurements under pulsed broadband illumination, we reveal markedly different hysteretic and transient behaviors in the two contact configurations. The SG device exhibits pronounced illumination‐history‐dependent transients and strongly power‐dependent transport, consistent with a significant contribution from local ionic polarization, trap‐mediated processes, and contact injection. In contrast, the MG device displays a more stable and weakly power‐dependent photoresponse. A phenomenological parallel‐channel model shows that the measured polarization‐induced voltage offset in a multi‐gap architecture can be expressed as a conductance‐weighted contribution of the local polarization potentials associated with the individual electrically active regions. These results provide an architecture‐dependent framework for understanding how contact configuration modulates mixed ionic–electronic transport and hysteresis in MAPbBr3 microwire devices.