High-Performance Pseudo-Bilayer Organic Solar Cells Enabled by Sequential Deposition of D18/Y6 Chloroform Solution

Abstract

Recently, sequential deposition (SD) fabricated pseudo-bilayer organic solar cells (OSCs) have achieved preferable performances compared to the long-term adopted bulk heterojunction (BHJ)-based devices, in which the solution-processing technique is the key to preparing the active layer of electron− donor materials and electron−acceptor materials. For devices with D18 as the electron−donor material and Y-serial small molecules as the electron−acceptor materials, however, one single solvent was seldom applied to prepare the corresponding high-performance SD OSCs. In this work, we adopted chloroform as the single solvent and successfully constructed high-performance SD OSCs based on D18 and Y6. Benefiting from the finely adjusting of the vertical phase distribution, the SD low molecular weight D18/Y6 pseudo-bilayer device realized high short-circuit current density (27.24 mA cm −2 ) and a champion efficiency of 17.94%, which surpassed the 17.36% value of the D18:Y16 device having a bulk heterojunction structure and the 7.81% result of the SD prepared Y6/D18-based device. This work demonstrates a single solvent strategy for fulfilling high-performance SD OSCs and reveals the reasons that account for the distinct performances of these OSCs fabricated by different approaches.

Pseudo-bilayered inverted organic solar cells using the Marangoni effect

“…Consequently, the PCEs of optimized PB OSCs are higher than those of their BHJ counterparts. 36,38–44 In addition, the PB architecture can effectively enhance the stability of OSCs because of the morphological robustness of phase separation. 36,45…”

“…Therefore, most PB OSCs (PCEs > 10%) have normal structures. [39][40][41]43,44,55 The structural constraint can result in stability issues partly because of the hygroscopicity [56][57][58] and acidity [59][60][61] of PEDOT:PSS, which is the most widely used substance for transporting holes from active layers. 62,63 In fact, the air stability (RH > 40%) of PEDOT-based OSCs with a normal structure was demonstrated to be low compared with that of ZnO-based OSCs with an inverted structure.…”

A facile synthetic approach based on thieno[3,4-c]pyrrole-4,6-dione to construct polymer donors for highly efficient organic solar cells

“…5, wherein the PCEs of PM6 and D18 are cited from other state-of-the-art works. 34,66–74 The devices constructed on the basis of PTTB-F:Y6, PTTB-F:N3, PTTB-F:BTP-eC9, PTTB-F:IT-4F and PTTB-F:PYT demonstrated impressive PCEs of 16.05%, 15.42%, 16.75%, 13.86% and 13.69%, respectively. These values, however, are lower than that (PCE = 18.06%) of the PTTB-T:L8-BO devices, as discussed above.…”

Advances in layer-by-layer processing for efficient and reliable organic solar cells

“…Liu et al achieved a PCE of 17.94% for the D18/Y6-based pseudo-bilayer device processed from CF as a single solvent (Table 3). 120 That means the bottom D18 layer can tolerate the CF processing of Y6. Meanwhile, the deposition of the D18 layer over the Y6 film led to a decrease in PCE to 7.8% due to the washing of the Y6 layer by CF.…”