From Molecular Cages to Functional Devices: Silsesquioxane Hybrid Platforms for Next-Generation Electronic Materials

Polyhedral oligomeric silsesquioxanes (POSS) and related silsesquioxanes provide an atomically precise platform for organic–inorganic hybrid electronics. Existing reviews mainly address synthesis, functionalisation, and application breadth; comparatively few connect molecular architecture to electronic function and benchmark the resulting devices against contemporary non-POSS records. This review is organised around that structure–property–device relationship. Each cage class—closed T8/T10/T12 cages, open-cage and double-decker frameworks, Janus cubes, ladder polymers, and ionic or fluorinated derivatives—is paired with the electronic function it enables; reported figures of merit are compared with current field records, and unresolved contradictions, trade-offs, and manufacturing barriers are stated explicitly. Device classes surveyed include light emission (OLEDs, perovskite LEDs, quantum-dot LEDs, and white LEDs), thin-film transistors and interlayer dielectrics, organic, perovskite, and dye-sensitised photovoltaics, and emerging platforms in memory, chemosensing, flexible electronics, and thermal management. We conclude that encapsulation resins, nanocrystal surface modifiers, and low-k dielectric formulations appear among the most promising candidates for translation beyond laboratory-scale demonstrations. Machine-learning-guided cage design, mixed-architecture networks, and fluorine-free routes to hydrophobicity are identified as the most credible routes to closing the remaining gaps.