Contact‐Architecture‐Dependent Mixed Ionic‐Electronic Transport in Solution‐Grown MAPbBr3 Microwire Photodetectors

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 MAPbBr3 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.