The Role of Solution Aggregation Property toward High-Efficiency Non-Fullerene Organic Photovoltaic Cells.

In organic photovoltaic cells, the solution-aggregation effect (SAE) is long considered a critical factor in achieving high power-conversion efficiencies for polymer donor (PD)/non-fullerene acceptor (NFA) blend systems. However, the underlying mechanism has yet to be fully understood. Herein, based on an extensive study of blends consisting of the representative 2D-benzodithiophene-based PDs and acceptor-donor-acceptor-type NFAs, it is demonstrated that SAE shows a strong correlation with the aggregation kinetics during solidification, and the aggregation competition between PD and NFA determines the phase separation of blend film and thus the photovoltaic performance.

A High-Performance Nonfused Wide-Bandgap Acceptor for Versatile Photovoltaic Applications.

Wide-bandgap (WBG) nonfullerene acceptors (NFAs) with nonfused conjugated structures play a critical role in organic photovoltaic (OPV) cells. Here, NFAs named GS-OEH, GS-OC6, and GS-ISO, with optical bandgaps larger than 1.70 eV, are synthesized without using the fused ring structures.

Facile Modification of a Noncovalently Fused-Ring Electron Acceptor Enables Efficient Organic Solar Cells.

Electron acceptors with nonfused aromatic cores (NCAs) have aroused increasing interest in organic solar cells due to the low synthetic complexity and flexible chemical modification, but the corresponding device performance still lags behind. Herein, we designed and synthesized two new quinoxaline-based NCAs, namely, QOC6-4H and QOC6-4Cl. Although both NCAs show good backbone coplanarity, QOC6-4Cl with chlorinated end groups exhibits higher extinction coefficient, enhanced crystallinity, and more compact π-π stacking, which is correlated with the stronger intermolecular interactions induced by chlorine atoms.

18.5% Efficiency Organic Solar Cells with a Hybrid Planar/Bulk Heterojunction.

The donor:acceptor heterojunction has proved as the most successful approach to split strongly bound excitons in organic solar cells (OSCs). Establishing an ideal architecture with selective carrier transport and suppressed recombination is of great importance to improve the photovoltaic efficiency while remains a challenge. Herein, via tailoring a hybrid planar/bulk structure, highly efficient OSCs with reduced energy losses (E s) are fabricated.

Single-Junction Organic Photovoltaic Cell with 19% Efficiency.

Improving power conversion efficiency (PCE) is important for broadening the applications of organic photovoltaic (OPV) cells. Here, a maximum PCE of 19.0% (certified value of 18.

Suppressing Energetic Disorder Enables Efficient Indoor Organic Photovoltaic Cells With a PTV Derivative.

Indoor organic photovoltaics (IOPVs) cells have attracted considerable attention in the past few years. Herein, two PTV-derivatives, PTVT-V and PTVT-T, were used as donor materials to fabricate IOPV cells with ITCC as the acceptor. The preferred orientation of the crystals changed from edge-on to face-on after replacing the ethylene in the backbones of PTVT-V by the thiophene in that of PTVT-T.

Simultaneous Improvement of Efficiency and Stability of Organic Photovoltaic Cells by using a Cross-Linkable Fullerene Derivative.

Improving power conversion efficiencies (PCEs) and stability are two main tasks for organic photovoltaic (OPV) cells. In the past few years, although the PCE of the OPV cells has been considerably improved, the research on device stability is limited. Herein, a cross-linkable material, cross-linked [6,6]-phenyl-C61-butyric styryl dendron ester (c-PCBSD), is applied as an interfacial modification layer on the surface of zinc oxide and as the third component into the PBDB-TF:Y6-based OPV cells to enhance photovoltaic performance and long-term stability.

1 cm Organic Photovoltaic Cells for Indoor Application with over 20% Efficiency.

Organic photovoltaic (OPV) technologies have the advantages of fabricating larger-area and light-weight solar panels on flexible substrates by low-cost roll-to-toll production. Recently, OPV cells have achieved many significant advances with power conversion efficiency (PCE) increasing rapidly. However, large-scale solar farms using OPV modules still face great challenges, such as device stability.

Achieving Over 15% Efficiency in Organic Photovoltaic Cells via Copolymer Design.

Ternary blending and copolymerization strategies have proven advantageous in boosting the photovoltaic performance of organic solar cells. Here, 15% efficiency solar cells using copolymerization donors are demonstrated, where the electron-withdrawing unit, ester-substituted thiophene, is incorporated into a PBDB-TF polymer to downshift the molecular energy and broaden the absorption. Copolymer-based solar cells suitable for large-area devices can be fabricated by a blade-coating method from a nonhalogen and nonaromatic solvent mixture.