Boag, N.M.; Nelson, K.; Montag, B.; Brand, Jennifer I.; and Dowben, Peter A., "The electronic structure of 1,2-PCB 10 H 11 molecular films: a precursor to a novel semiconductor" (2006 Abstract: The band gaps and electronic structure of un doped fi lms of molecular icosahedra of closo-1-phospha-2 carbadodecaborane (1,2-PCB 10 H 11 ) are reported.

We compare the molecular films of three different isomers of closo-dicarbadodecaborane (orthocarborane (1,2-C2B10H12), metacarborane (1,7-C2B10H12), paracarborane (1,12-C2B10H12)) and two related icosahedral cage molecules, 1-phospha-2-carbadodecaborane (1,2-PCB10H11) and 1-phospha-7-carbadodecaborane (1,7-PCB10H11) adsorbed on a variety of substrates. While the experimental electronic structure from combined photoemission and inverse photoemission studies of the molecular films are in good agreement with semiempirical calculations for the isolated molecule, there is a shift in the chemical potential for each molecule. The experimental position of the molecular chemical potential implicates an influence of both interface and adsorbate dipole.

The electronic structure and highest occupied to lowest unoccupied molecular orbital gap of undoped films of the molecular icosahedra of closo-1-phospha-7-carbadodecaborane (1,7-PCB10H11, meta-phosphacarborane) are reported. For 1,7-PCB10H11 adsorbed on Au and Ag, the Fermi level is placed closer to the lowest unoccupied molecular orbital than has been observed with closo-1-phospha-2-carbadodecaborane (1,2-PCB10H11, ortho-phosphacarborane) adsorbed on Au and Ag.