Rational Regulation of the Molecular Aggregation Enables A Facile Blade‐Coating Process of Large‐area All‐Polymer Solar Cells with Record Efficiency

Abstract

Developing robust materials is very critical and faces a big challenge for high‐performance large‐area all‐polymer solar cells (all‐PSCs) by printing methods. Herein, the authors combine the advantages of the terpolymerization strategy with the non‐conjugated backbone strategy to regulate the molecular aggregation rationally during the film‐forming printing process, facilitating a facile printing process for large‐area all‐PSCs. A series of terpolymer acceptors PYSe‐Clx (x = 0, 10, 20, and 30) is also developed, which can effectively fine‐tune the morphology and photoelectric properties of the active layer. The PBDB‐T: PYSe‐Cl20‐based all‐PSC delivers a significantly improved power cconversion efficiency (PCE) than the one with PBDB‐T: PYSe (14.21% vs 12.45%). By addition of a small amount of non‐conjugated polymer acceptor PTClo‐Y, the ternary all‐PSC reaches a PCE of 15.26%. More importantly, the regulation of molecular aggregation enables a facile blade‐coating process of the large‐area device. A record PCE of 13.81% for large‐area devices (1.21 cm2) is obtained, which is the highest value for large‐area all‐PSCs fabricated by blade‐coating. The environmentally friendly solvent processed large‐area device also obtains an excellent performance of 13.21%. This work provides a simple and effective molecular design strategy of robust materials for high‐performance large‐area all‐PSCs by a printing process.

Regulation of Polymer Configurations Enables Green Solvent‐Processed Large‐Area Binary All‐Polymer Solar Cells With Breakthrough Performance and High Efficiency Stretchability Factor

“…During the slow film‐forming process of the BC method, the highly crystalline PSMAs tend to form island film morphology with severe aggregations. [ 26 ] The low‐quality film caused by the mismatch between the intrinsic fast aggregation of the polymer acceptor and the technically slow film‐formation of the BC method becomes the key reason for the large PCE loss from small‐area SC devices to large‐area BC devices. Therefore, how to smoothly transfer from SC small‐area devices to BC large‐area devices with minimal PCE loss is a big challenge, which requires developing high‐performance active materials to withstand different processes.…”

“…[ 27,33 ] Recently, we also found that the integration of non‐conjugated units and an interrupted sequence of random backbone effectively prevented the active layer from over‐aggregation, facilitating a slow BC process. [ 26,33,34 ] Inspired by this, in this work, we report two types of new terpolymer acceptors, PYT X ‐A and PYT X ‐B ( X = Cl or H) with different configurations by random polymerization, in which non‐conjugated units are introduced into the highly efficient polymer acceptor PY‐IT by partly replacing the thiophene bridge and conjugated Y core, respectively, as shown in Scheme a. From the perspective of the polymer configurations, we systematically studied the influence of the different replacements by non‐conjugated units on the molecular spatial geometry, film packing arrangement, optoelectronic properties, device performance, and mechanical properties of the two types of terpolymer acceptors.…”

Overcoming Disordered Preaggregation in Liquid State for Highly Efficient Organic Solar Cells Printed from Nonhalogenated Solvents

“…[ 32 ] The crystalline coherence length (CCL) (Tables S1–S2, Supporting Information) of π–π stacking peaks of D18:BTP‐eC9 DB_XY film (2.76 nm) was increased compared with that of SC_CF films (2.60 nm), indicating higher degree of crystallinity resulted from DB_XY. [ 33 ] For D18:Y6 films (Figure 2g,h), the strong π–π stacking diffraction peak at ≈1.76 Å −1 in the OOP direction of SC_CF film indicates a preferential face‐on orientation, which showed reduction in both intensity and anisotropy for DB_XY films. More quantitatively, the coherence length calculated from π–π stacking peaks in the OOP direction decreased from 3.02 to 2.79 nm when changing from SC_CF to DB_XY.…”

Y-Series-Based Polymer Acceptors for High-Performance All-Polymer Solar Cells in Binary and Non-binary Systems

“…Despite a slight decrease in the V oc due to the low LUMO of PYCl-T, J sc and FF of the ternary-blend-based PSC were improved, resulting in a higher PCE of 16.62% compared to those of the binary PSCs (Table ). Utilizing terpolymer PYSe-TCl20 (Figure ) and polymer acceptor PTCl o -Y (Figure ) with non-conjugated linkages, Chen et al demonstrated the significance of D:A:A′-type ternary systems . The PCE value of the ternary blend of PBDB-T:PYSe-TCl20:PTCl o -Y-based all-PSCs was 15.26%.…”

“…Utilizing terpolymer PYSe-TCl20 (Figure 3) and polymer acceptor PTCl o -Y (Figure 4) with non-conjugated linkages, Chen et al demonstrated the significance of D:A:A′-type ternary systems. 91 The PCE value of the ternary blend of PBDB-T:PYSe-TCl20:PTCl o -Y-based all-PSCs was 15.26%. These findings demonstrated that the collaborative effect of terpolymerization with a non-conjugated backbone and a ternary system can effectively regulate the morphology of blends and improve the performance of the device.…”