Emerging Upconversion Nanoparticle Hybrid Heterostructures for Advanced Optoelectronic Devices and Intelligent Applications

ABSTRACT Upconversion nanoparticle (UCNP)‐based hybrid heterostructures are emerging as a versatile platform for next‐generation optoelectronic devices and intelligent technologies, owing to their capability to convert low‐energy near‐infrared (NIR) photons into higher‐energy visible or ultraviolet (UV) emission. This review provides a critical overview of recent advances in UCNP design, interface engineering, and hybrid integration with organic, inorganic, and low‐dimensional materials, and clarifies how structural and compositional tailoring governs optical coupling and device performance. The diverse optoelectronic applications of UCNP hybrid systems, including photodetectors, solar cells, light‐emitting diodes (LEDs), and optical memories, are systematically discussed with particular emphasis on energy transfer and charge transport processes that underpin efficiency enhancement. Persistent challenges such as spectral mismatch, interfacial losses, and scalable fabrication are analyzed from both materials and device perspectives. Finally, future opportunities for UCNP hybrid heterostructures in intelligent sensing, neuromorphic information processing, biomedical applications, and space‐related optoelectronics are outlined, highlighting their potential to bridge photon conversion, information processing, and intelligent optoelectronic functionalities within unified material platforms.