A series of new one-dimensional (1D) CuI-based inorganic-organic hybrid semiconductors have been designed and synthesized, namely, 1D-Cu₆I₉(dmpi)₃ (1), 1D-Cu₄I₆(5asn)₂(2), 1D-Cu₄I₆(Nhex)₂(3) and 1D-Cu₂I₆(Npipz)₂ (4) (dmpi = N,N-dimethylpiperidinium, 5asn = 5-azaspiro[4.4]nonan-5-ium, Nhex = cyclohexanaminium, Npipz = 1-methylpiperazine-1,4-diium). All structures are composed of aliphatic cations and various 1D CuI anionic chains that interact through ionic bonding. Due to their wide bandgaps, all materials display ultraviolet (UV) emission between 340 – 390 nm, with internal quantum yields (IQYs) up to 6.4%. All compounds are solution-processable due to their ionic bonding nature and have excellent thermal stability up to T_d = 260 C, as well as impressive structural stability over long time periods. Due to the use of aliphatic cations as structure directing agents, the photophysical properties of these materials are dominated by their inorganic components, as confirmed by electronic structure calculations. Additionally, their non-toxicity and facile synthesis make them highly practical materials for commercial use. These findings provide helpful insight into the future development of high-performance wide bandgap semiconductors that may have promise in various UV-emitting applications.

Simon Teat

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