Organic-inorganic hybrid perovskites have demonstrated exceptional photovoltaic properties, making them highly promising for solar cells and photodetectors (PDs). However, the organic components of these materials are vulnerable to heat and strong light illumination, limiting their application prospects. All-inorganic cesium-based perovskite PDs, on the other hand, possess enhanced thermal tolerance and stability, making them ideal for perovskite applications. The utilization of a ternary mixture solvent and additives in combination with single crystal (SC) growth has enabled the production of highly crystalline SCs with a defect density of 3.79 × 10⁹ cm^-3. The performance of the SC PDs had been evaluated using metal-semiconductor-metal devices, which demonstrated excellent results with a dark current as low as 0.198 μA at 10 V bias, on-off ratios exceeding 10³, and a response time of shorter than 1 ms.

With a striking explosion of digital information, organic–inorganic halide perovskite (OHP) memristors have been regarded as a promising solution to break the von Neumann bottleneck as the nonvolatile computing‐in‐memory architecture. However, toxicity and stability under ambient conditions are two critical issues for practical applications. Here, lead‐free MASnI₃ (MASI) perovskites are reported with improved resistive switching (RS) performance via defects passivating by introducing PEACl. In‐Sn/PEACl‐MASI/PEDOT:PSS/ITO memristor arrays (10 × 10) exhibit reproducible RS with low SET/RESET voltage (V_SET/V_RESET, +0.58/−0.49 V), ultrahigh ON/OFF ratio (8.5 × 10³), stable endurance (2 × 10³ cycles), excellent retention (2 × 10⁴ s), high device yield (88%), and multilevel storage. RS remains robust in harsh environments, including high temperature and humidity, long‐term light irradiation, and open‐air conditions. Importantly, a complete physical simulation model that quantitatively and accurately describes RS in vacancy concentration, temperature, and electric potential is proposed originating from conductive filaments formation/rupture. Additionally, PEACl‐MASI memristors are successfully fabricated on polyethylene terephthalate (PET) and Si substrates to explore the potential for large‐scale application on different substrates. The PEACl‐MASI memristors provide an opportunity to develop the next generation of high‐performance and environmentally robust multilevel information storage devices.