Highly Efficient Ternary‐Blend Polymer Solar Cells Enabled by a Nonfullerene Acceptor and Two Polymer Donors with a Broad Composition Tolerance

Abstract

In this work, highly efficient ternary-blend organic solar cells (TB-OSCs) are reported based on a low-bandgap copolymer of PTB7-Th, a medium-bandgap copolymer of PBDB-T, and a wide-bandgap small molecule of SFBRCN. The ternary-blend layer exhibits a good complementary absorption in the range of 300-800 nm, in which PTB7-Th and PBDB-T have excellent miscibility with each other and a desirable phase separation with SFBRCN. In such devices, there exist multiple energy transfer pathways from PBDB-T to PTB7-Th, and from SFBRCN to the above two polymer donors. The hole-back transfer from PTB7-Th to PBDB-T and multiple electron transfers between the acceptor and the donor materials are also observed for elevating the whole device performance. After systematically optimizing the weight ratio of PBDB-T:PTB7-Th:SFBRCN, a champion power conversion efficiency (PCE) of 12.27% is finally achieved with an open-circuit voltage (V ) of 0.93 V, a short-circuit current density (J ) of 17.86 mA cm , and a fill factor of 73.9%, which is the highest value for the ternary OSCs reported so far. Importantly, the TB-OSCs exhibit a broad composition tolerance with a high PCE over 10% throughout the whole blend ratios.

High‐Performance Green Solvent Processed Ternary Blended All‐Polymer Solar Cells Enabled by Complementary Absorption and Improved Morphology

“…The generated holes can barely be extracted from the HOMO of PBTA‐BO to the anode as they are instead first transferred to the HOMO of PNTB and then extracted to the anode. Similar phenomena have also been observed in other ternary blended systems featuring comparable energy‐level alignments . It is also worth noting that after heating at a moderate temperature of 80 °C for 24 h in glovebox, the all‐PSCs retained over 90% of their original PCE values (Figure S3, Supporting Information), and they also retained over 88% of their original PCE values (Figure S4, Supporting Information) after continuous illumination under AM 1.5 G at 100 mW cm −2 for 24 h in glovebox.…”

Dithieno[3,2‐b:2′,3′‐d]pyrrol Fused Nonfullerene Acceptors Enabling Over 13% Efficiency for Organic Solar Cells

“…[55][56][57][58] We optimize the processing conditions, such as solvent, additive volume ratio, and thermal annealing temperature with donor/acceptor weight ratio of 1:1 ( Figure S12 and Table S2, Supporting Information). The well-known PBDB-T was selected as polymer donor due to its superior photoelectric properties and complementary absorption bands to the NIR absorption acceptors.…”

Morphology Control Enables Efficient Ternary Organic Solar Cells

“…[36][37][38] Recent developments in NFAs offer a wider choice of acceptor materials for ternary devices. [39][40][41][42][43][44][45] In terms of ternary blend incorporating two NFAs, impressive progresses have been also obtained. [21,22] Different ternary blends containing one NFA paired with two donors or one donor/one fullerene derivative exhibited high PCEs over 12%.…”

“…[4,5] Consequently, much effort has been devoted to the study of NFA-based ternary OSCs. [39][40][41][42][43][44][45] In terms of ternary blend incorporating two NFAs, impressive progresses have been also obtained. [39][40][41][42][43][44][45] In terms of ternary blend incorporating two NFAs, impressive progresses have been also obtained.…”