Improving Photovoltaic Performance of Non‐Fullerene Polymer Solar Cells Enables by Fine‐Tuning Blend Microstructure via Binary Solvent Mixtures

Abstract

Studies of the relationship between blend microstructure and photovoltaic performance are becoming more common, which is a prerequisite for rationally improving device performance. Non‐fullerene acceptors usually have planar backbone conformation and strong intermolecular packing, normally resulting in excessive phase separation. Herein, an effective co‐solvent blending strategy to turn the molecular organization of a chlorinated small molecule acceptor Y6‐2Cl and phase separation of the corresponding active layer with PM6 as donor is demonstrated. The in situ photoluminescence measurements and relevant morphological characterizations illustrate that the film‐forming process is fine‐turned when using the mixtures of chloroform (CF) and chlorobenzene (CB) solvents, and the blend showed high domain purity with suitable phase‐separated networks. Thus, better exciton dissociation and charge generation, more balanced charge transport, and less recombination loss are obtained in the co‐solvent blade‐coated devices. As a result, a maximum power conversion efficiency (PCE) of 16.17% is achieved, which is much higher than those of CF‐ and CB‐bladed devices (14.08% and 11.44%, respectively). Of note is that the use of this co‐solvent approach in the other two high‐performance photovoltaic systems is also confirmed, demonstrating its good generality of employing in the printing organic solar cells.

Tailoring polymer acceptors by electron linkers for achieving efficient and stable all-polymer solar cells

“…4 D). It seems plausible that the molecular crystallinity and phase compatibility are not directly related, supported by our analysis results, which is inconsistent with some previous findings [ 35 , 54 , 55 ], especially in N2200-based systems [ 56–58 ]. Nonetheless, we can conclude with care that both intermolecular interactions and D-A compatibility simultaneously determined the blend morphological characteristics, which result in the performance differences of all-polymer systems based on various electron linkers (Fig.…”

Impact of substituents on the performance of small-molecule semiconductors in organic photovoltaic devices via regulating morphology

“…Toward this end, in situ analysis of morphology should be of critical importance; indeed, in situ light absorption, photoluminescence, and X-ray scattering analyses are becoming increasingly common in OPV research. [163][164][165][166] We also note that the use of computer-aided approaches should be widely extended to accelerate the understanding of the structuremorphology-performance relationship of OPV materials. There have been already several studies in this context, [167][168][169][170][171][172][173] and research efforts in this area will aid achieving PCEs nearing the theoretical limit.…”

Asymmetric Isomer Effects in Benzo[c ][1,2,5]thiadiazole‐Fused Nonacyclic Acceptors: Dielectric Constant and Molecular Crystallinity Control for Significant Photovoltaic Performance Enhancement

“…Apart from J SC , the variations in FF of three OSCs were also revealed by employing transient photocurrent (TPC) and transient photovoltage (TPV) techniques. [59] The charge extraction time can be obtained by fitting the TPC decay curves under short circuit condition. As depicted in Figure 3e, the photocurrent decay time of PM6:BP6T-4F and PM6:ABP6T-4F are 0.30 and 0.23 µs, respectively, indicating that PM6:ABP6T-4F exhibited a more efficient charge extraction, leading to faster charge sweepout than PM6:BP6T-4F.…”