%0 journal article
%@ 2052-2525
%A Märkl, R., Hohn, N., Hupf, E., Bießmann, L., Körstgens, V., Kreuzer, L., Mangiapia, G., Pomm, M., Kriele, A., Rivard, E., Müller-Buschbaum, P.

%D 2020
%J IUCrJ
%N 2
%P 268-275 
%R doi:10.1107/S2052252520000913
%T Comparing the backfilling of mesoporous titania thin films with hole conductors of different sizes sharing the same mass density
%U https://doi.org/10.1107/S2052252520000913
2 
%X Efficient infiltration of a mesoporous titania matrix with conducting organic polymers or small molecules is one key challenge to overcome for hybrid photovoltaic devices. A quantitative analysis of the backfilling efficiency with time-of-flight grazing incidence small-angle neutron scattering (ToF-GISANS) and scanning electron microscopy (SEM) measurements is presented. Differences in the morphology due to the backfilling of mesoporous titania thin films are compared for the macromolecule poly[4,8-bis­(5-(2-ethyl­hexyl)­thio­phen-2-yl)benzo[1,2-b;4,5-b′]di­thio­phene-2,6-diyl-alt-(4-(2-ethyl­hexyl)-3-fluoro­thieno[3,4-b]thio­phene-)-2-carboxyl­ate-2-6-diyl)] (PTB7-Th) and the heavy-element containing small molecule 2-pinacol­boronate-3-phenyl­phen­anthro[9,10-b]telluro­phene (PhenTe-BPinPh). Hence, a 1.7 times higher backfilling efficiency of almost 70% is achieved for the small molecule PhenTe-BPinPh compared with the polymer PTB7-Th despite sharing the same volumetric mass density. The precise characterization of structural changes due to backfilling reveals that the volumetric density of backfilled materials plays a minor role in obtaining good backfilling efficiencies and interfaces with large surface contact.