Dielectric Breakdown of 2D Hybrid Organic-Inorganic Perovskites

2D hybrid organic-inorganic perovskites (HOIPs) have emerged as promising low-cost, high-performance direct bandgap semiconductor materials in a plethora of energy and electronic applications, offering enhanced environmental stability compared to their conventional 3D analogs. While the breakdown of HOIPs under an electric field is commonly found in optoelectronic devices under reverse bias conditions and during the switching of memories/memristors based on these materials, a fundamental understanding of their dielectric breakdown behavior is still missing. Here, we investigate the dielectric breakdown of a prototypical family of 2D HOIPs, (BA)₂MA_n-1PbnI_3n+1 (BA = butylammonium, MA = methylammonium cation, and n = 1 to 5) in the out-of-plane direction, using conductive atomic force microscopy. The dielectric breakdown of mechanically exfoliated 2D HOIP flakes manifests a rapid current rise in the I-V curve, and results in a pit locally. The irreversible defects generated by the breakdown are largely concentrated on the top layer, resulting in layer-by-layer damage and material removal in 2D HOIPs from the top. The breakdown voltage V_BD increases with the thickness while the breakdown strength follows a decline trend. A lower ramping rate gives a lower E_BD value owing to the longer time provided for the defects to nucleate and grow. The distribution of the breakdown characteristics of 2D HOIPs follows the Weibull statistics, and the Weibull modulus shows an increasing trend as the thickness increases, which implies the breakdown process can be described by the classical percolation model. 2D HOIPs with higher n number have higher E_BD, probably due to better electrical and thermal conductivities. The measured E_BD is on the order of 10⁸ V/m, showing the great intrinsic resilience of 2D HOIPs to dielectric failure. Our results provide indispensable insights into the failure of 2D HOIPs under the electrical field in electronic and optoelectronic devices, which are critically needed to improve the stability and durability of the devices. The high breakdown strength (on par with or better than that of many dielectric materials) and the band alignment tunable through the chemical composition, together with the dangling bond-free 2D interface and the scalable solution processability, promise 2D HOIPs great potential in application as dielectric materials for future 2D electronic devices.