Principles and advances in spin light-emitting diodes

Abstract Spin light-emitting diodes (spin-LEDs), which converts carrier spin information to optical polarization, are important for modern display application and future technologies including spin-based electronic circuits and quantum information science. Spin-LEDs operate through spin-polarized carrier injection, directly converting spin angular momentum into photon helicity. Recent advances in materials and mechanism understanding have significantly improved spin injection efficiency and device performance. This review discusses the fundamental principles and operation mechanisms of spin-LEDs, where we examine conventional spin injection approaches and their constraints. We then highlight the emerging role of chiral-induced spin selectivity (CISS) in spin-LEDs, exploring how this novel mechanism could enhance circularly polarized electroluminescence efficiency and enable new device architectures. Finally, we provide perspectives on current challenges.