A flexible nickel phthalocyanine resistive random access memory with multi-level data storage capability

•Trap concentration is important for trap-controlled RRAM with SCLC conduction.•A flexible multi-level NiPc RRAM is explored due to its high trap-concentration.•NiPc film provides numerous traps, enabling effective resistance switching.•NiPc RRAM shows the flexibility, reliability, uniformity and multi-level capability.•A fast operation speed is also primary for NiPc RRAM.