Abstract
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-ethyl-hexyl)-thio-phen-2-yl)benzo[1,2-b;4,5-b']di-thio-phene-2,6-diyl-alt-(4-(2-ethyl-hexyl)-3-fluoro-thieno[3,4-b]thio-phene-)-2-carboxyl-ate-2-6-diyl)] (PTB7-Th) and the heavy-element containing small molecule 2-pinacol-boronate-3-phenyl-phen-anthro[9,10-b]telluro-phene (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.
Highlights
Creating maximum surface contact between functional materials is one of the most challenging and vital aspects of functional interface design (Graetzel et al, 2012)
Mesoporous titania films synthesized using a sol–gel diblock copolymer templating method are subsequently backfilled with the macromolecule PTB7-Th and the custom-made small molecule PhenTe-BPinPh
As the two materials are of different material classes, namely a polymer and a small molecule, many structural properties differ
Summary
Creating maximum surface contact between functional materials is one of the most challenging and vital aspects of functional interface design (Graetzel et al, 2012). We investigate the backfilling of al., 2013; Bencheikh et al, 2015) It has been two different materials, namely the conjugated polymer shown that interaction with additives and ternary components poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b0]- in OPVs can greatly enhance device performance, thereby dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4- opening a large range of combination opportunities (Sun et al, b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th) and the 2016). Much attention has been focused on the photovoltaic performance of PTB7-Th and the exciton lifetime-enhancing properties of heavy-element containing small molecules, reported work concerning the infiltration behavior of these materials into inorganic mesoporous structures is limited As these materials appear promising for future hybrid photovoltaic configurations, their suitability for creating desirable interfaces is of special interest. Our resulting morphological findings lay the groundwork for future research on the successful incorporation of PTB7-Th and PhenTe-BPinPh into hybrid photovoltaic devices and contribute a deeper understanding of influences on infiltration efficiency
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
