Study of the doping effect on imperfect morphology at photovoltaic heterojunctions in bilayer organic solar cells

Abstract

The efficient doping of a donor–acceptor copolymer is controlled by the charge–quadrupole interaction between the dopant and the respective units to improve the photovoltaic performance by alleviating the energy barrier for charge separation.

Direct C–H Arylation-Derived Donor Polymers Afford PCEs over 10% for Organic Solar Cells

“…Thus, the surface ratio of the π-layer-stacking region to the alkyl chains can determine the orientation of the polymer chain in the solid films. The higher the surface ratio of the π-layer stacking, the more likely the face-on orientation will be formed . The PM6- CH solid thin film might have less face-on orientation owing to its lower ratio of the surficial π-layer stacking region compared to PM6- St , as revealed by UV–vis spectroscopy (Figure b).…”

“…The higher the surface ratio of the π-layer stacking, the more likely the face-on orientation will be formed. 54 The PM6-CH solid thin film might have less face-on orientation owing to its lower ratio of the surficial π-layer stacking region compared to PM6-St, as revealed by UV−vis spectroscopy (Figure 1b).…”

“…In CHCl 3 solutions, PM6-CH exhibits a broader absorption with a larger extension to shorter wavelengths compared to PM6-St, whereas PM6-St showed a sharp peak at 613 nm. The ratio of 0−0 and 0−1 peak intensities of PM6-CH in solution decreases relative to PM6-St, indicating the enhanced H-type aggregation of PM6-St. 54 The preaggregation of the conjugated polymers in solutions can typically influence their π−π stacking behavior and morphology of the spin-coated thin solid films. In thin solid films, both PM6-CH and PM6-St exhibit a wider absorption window (350−725 nm) with double absorption peaks at 573 and 632 nm, respectively.…”

A paradigm study of polymer donor diluted bulk heterojunction films for application in semitransparent organic photovoltaics

“…The sacri-ced domain purity with less D18 content is hard to be compensated by traditional optimization methods; however, our recent ndings reveal dopant addition as a feasible strategy to enhance the FF in such imperfect morphology. 15,23 We chose N-DMBI as an n-dopant (Fig. S1 †), and added it separately to the D18:Y6 and PM6:Y6 diluted BHJ lm.…”

“…where J D represents the double-carrier current, and J p(n) denotes the hole (electron) current density (see details in ref. 23). The g pre values are separately 0.084, 0.072, and 0.044 for devices with D : A ratios of 0.35 : 1, 0.30 : 1, and 0.25 : 1.…”