Tunable quantum coherence of organic luminescent radical qubits centered in star-like block copolymers and self-assembling nanostructures

Electronic or nuclear spins such as inorganic ‘nitrogen-vacancy’ centers in diamond and other defects in silicon represent a promising type of quantum bits (qubits) for applications in quantum information processing, data storage as well as quantum sensing. However, it remains challenging to achieve scalable and spatially defined organization of a large number of spins as qubits. Therefore, development of new materials and technologies to regulate spin-spin distance and interaction plays an important role in preservation of quantum coherence and realization of coherent exchange of information between spin qubits. Herein, we report that spatially defined organization of organic radicals as electronic spins can be realized via a strategy of block copolymer self-assembly. We demonstrate quantum coherence and spin-lattice relaxation of organic luminescent radical spins can be facilely tuned using a library of well-defined star-like block copolymers containing a common core of tris[4-(p-benzyl)-2,6-dichlorophenyl]methyl radical in the center, from which diblock polyesters are grafted via controllable ring-opening polymerization. The fine tuning of the incompatibility and the volume ratio of the two blocks of polyesters leads to not only a series of self-assembling patterns (i.e., spheres, cylinders, lamellae, and gyroids) with phase-separation of the spins in the nanometer scale, but also tunable spin-lattice relaxation dynamics and spin coherence lifetimes that strongly depend on the lengths and rigidities of the polymeric matrices surrounding the organic radicals as molecular spins. Such strategy of block copolymer self-assembly may offer a generally applicable approach to integrating and organizing molecular spins as promising qubits into scalable architectures and functional devices towards cutting-edge applications in quantum information processing, quantum computation and spintronics.