Lead-free halide perovskite (LFHP) materials have recently received a lot of attention in optoelectronic applications due to their low toxicity and outstanding optical characteristics. Simultaneously, the increased thrust for flexible, wearable, and lightweight optoelectronic devices is driving improvements in sensor and actuator technology. In this context, flexible piezoelectric polymer composites based on LFHPs are gaining popularity due to their exceptional piezoelectric, pyroelectric, ferroelectric, and optical traits. Thus, this investigation presents long-term stable lead-free rubidium copper chloride (Rb