Planar Benzofuran Inside-Fused Perylenediimide Dimers for High V_OC Fullerene-Free Organic Solar Cells

Abstract

Bulk heterojunction organic solar cells based on perylenediimide (PDI) derivatives as electron acceptors have afforded high power conversion efficiency (PCE) but still lagged behind fullerene-based analogues. Design of novel molecular structures by adjusting the PDI ring and/or connection mode remains the breakthrough point to improve the photovoltaic performance. After introducing benzofuran at the inside bay positions and being linked with a single bond and a fluorene unit, mandatory planar PDI dimers were achieved and named FDI 2 and F-FDI 2 . Both acceptors show high-lying LUMO energy levels and realize high V OC beyond 1.0 V when using the classic polymer of PBDB-T as an electron donor. However, FDI 2 and F-FDI 2 gave totally different photovoltaic performance with PCEs of 0.15 and 6.33%, respectively. The central fluorene linkage increased the miscibility of materials and ensured a much higher short-circuit current because of the formation of suitable phase separation. Our results demonstrated that utilizing the mandatory planar skeleton of PDI dimers is a simple and effective strategy to achieve high-performance nonfullerene electron acceptors, and the modulation of central conjugated units is also vital.

Benzodithiophene‐Fused Perylene Bisimides as Electron Acceptors for Non‐Fullerene Organic Solar Cells with High Open‐Circuit Voltage

“…A PCE of 6.63 % could be achieved with photoresponse in the visible light region. More importantly, the solar cells provided a high V oc of 1.14 V, among the highest V oc s in OSCs to the best of our knowledge . The high V oc and visible light photoresponse indicate that the materials developed in this work have the great potential application in tandem OSCs…”

Recent Advances of Furan and Its Derivatives Based Semiconductor Materials for Organic Photovoltaics

“…synthesized two PDI‐based acceptors, in which introducing benzofuran at the inside bay positions and being linked with a single bond and a fluorene unit, producing molecules PCFA2 and PCFA3 . [ 305 ] Since the introduction of fluorene could facilitate molecular torsion, reducing intermolecular over‐aggregation of PCFA3 and achieving increased miscibility with donor material, therefore, the PBDB‐T: PCFA3 combination realized higher PCE of 6.33% than that of PCFA2 .…”

Molecular design towards two-dimensional electron acceptors for efficient non-fullerene solar cells

“…However, the strong aggregation hinders the formation of high-quality films for application, which was eventually exempted by the design of a three-dimensional strategy to weaken the crystallinity of the PDI molecules [19][20][21][22][23][24][25][26][27][28][29] . A-D-A SMAs usually possess near-infrared absorption, linear geometry, and tunable molecular crystallization and aggregation, all of which can be easily tune via structural evolution [30][31][32][33][34][35][36][37][38][39][40][41][42] . For example, modification on the aromatic core (such as indacenodith iophene, indacenodithieno[3,2-b]thiophene, A 2 -A 1 -D-A 1 -A 2 type aromatic core and more) [ 37 , 41 , 42 ], end-capped groups (such as rhodamine, 2-(3-oxo-2,3-dihydroinden-1-ylidene) and more) [ 35 , 40 ], and sidechains (such as phenyl side-chains, thienyl side chain and more) [ 32 , 38 ] of A-D-A small molecules could enable versatile electronic properties as well as improved photovoltaic performance.…”