Molecular orientation in polymer/fullerene blend films and the influence of annealing

Photodegradation of C‐PCPDTBT and Si‐PCPDTBT: Influence of the Bridging Atom on the Stability of a Low‐Band‐Gap Polymer for Solar Cell Application

“…As an example, it was found for P3HT that the ordering and aggregation of the polymer chains can vary at interfaces and surfaces, for example, by comparing C 1s and S 1s X-ray absorption spectra with different surface sensitivities (see the Supporting Information of Ref. [34]). Moreover, it was shown for this polymer that the orientation and thus the pelectron density distribution at the outermost surface can be even controlled.…”

Tailoring ultra-fast charge transfer in MoS2

“…16 Ultra-fast electron dynamics can be studied using several spectroscopic techniques. X-ray absorption (XAS) is commonly used to study for example molecular donor-acceptor systems, 17 pump-probe spectroscopy 18 for dynamics in low energy excited systems, e.g. pump-probe transient absorption spectroscopy has been used to study electronic coupling between MoS 2 monolayers and Ag nanoparticles.…”

Combining theory and experiment for X-ray absorption spectroscopy and resonant X-ray scattering characterization of polymers

“…Since NEXAFS is sensitive to specific functional groups and bonds, materials that are composed of the same elements, for example polystyrene and polyethylene which both contain just carbon and hydrogen, can have very distinct NEXAFS profiles. NEXAFS is itself a useful tool in polymer science, and has been widely used to examine thin film properties such as surface composition [15][16][17][18] and molecular orientation in ordered polymers [19][20][21][22][23]. Furthermore, absorption differences between polymers can be utilized for chemical sensitivity in real space imaging of thin films via scanning transmission X-ray microscopy (STXM) [24][25][26][27][28][29][30][31].…”

“…Only limited work has been done to predict NEXAFS of semiconducting polymers, but these studies demonstrate its potential and utility. For example, simulations have been able to help assign core-level transitions needed for orientation analysis [43,20] (Figure 2), and help make connections between excited state delocalization and the formation of free charges versus excitons [51]. The combination of theory and experiment for X-ray absorption spectroscopy…”

“…Even though these K edges start to go beyond the energy range of many soft X-ray beamlines, there is much interest to increase capabilities in this "tender" X-ray (2 keV-7 keV) regime. Although typically less common due to the limited number of endstations that can perform XAS or RSoXS near the sulfur and phosphorus K edges, notable work has been done on sulfur edge XAS to probe molecular orientation of semiconducting oligothiophenes such as α-sexithiophene [80][81][82], polythiophenes [83][84][85]20], and low-bandgap donoracceptor polymers [84,20,86]. Assigning the transitions near the sulfur K edge is difficult not only because of the limited body of work published, but also due to challenges such as π * and σ * peaks being very close in energy.…”