Three Iodobismuthates Hybrids Displaying Mono-nuclear, Dimer and 1-D Arrangements Templated by 1,4-diazabicyclo[2.2.2]octane Derivatives: Semiconductor and Photocurrent Response Properties

The structures, semiconductor and photocurrent response properties of three 1,4-diazabicyclo[2.2.2]octane derivative-templated iodobismuthates, (Et2DABCO)3(BiI6)2 (1), (i-Pr2DABCO)2(Bi2I10) (2), [(Me2DABCO)2(Bi2I10)2] n (3) (Et2DABCO2+ = N,N′-diethyl-1,4-diazabicyclo[2.2.2] octane, i-Pr2DABCO2+ = N,N′-diisoproyl-1,4-diazabicyclo[2.2.2] octane, Me2DABCO2+ = N,N′-dimethyl-1,4-diazabicyclo[2.2.2] octane), are reported. Based on the templates with different substitutents on 1,4-diazabicyclo[2.2.2]octane, mono-nuclear ((BiI6) 3 − for 1), dimer ((Bi2I10) 4 − for 2) and 1-D chain ((BiI5) n 2n− for 3) can be obtained. C-H···I hydrogen bonds contribute to the structural extension to 2-D layer (for 2) and 3-D network (for 3). Their absorption spectra were investigated, and energy band gaps of 2.24/1.73/1.44 eV indicate their narrow-gap semiconductor natures. Their photocurrent response properties were also discussed. Finally, theoretical calculation was executed to give structure-properties correlation.