The ternary strategy has been widely identified as an effective approach to obtain high‐efficiency organic solar cells (OSCs). However, for most ternary OSCs, the nonradiative voltage loss lies between those of the two binary devices, which limits further efficiency improvements. Herein, an asymmetric guest acceptor BTP‐2F2Cl is designed and incorporated into a PM1:L8‐BO host blend. Compared with the L8‐BO neat film, the L8‐BO:BTP‐2F2Cl blend film shows higher photoluminescence quantum yield and larger exciton diffusion length. Introducing BTP‐2F2Cl into the host blend extends its absorption spectrum, improves the molecular packing of host materials, and suppresses the nonradiative charge recombination of the ternary OSCs. Consequently, the power conversion efficiency is improved up to 19.17% (certified value 18.7%), which represents the highest efficiency value reported for single‐junction OSCs so far. The results show that improving the exciton behaviors is a promising approach to reducing the nonradiative voltage loss and realizing high‐performance OSCs.

Single‐Junction Organic Solar Cells with 19.17% Efficiency Enabled by Introducing One Asymmetric Guest Acceptor

Flexible perovskite solar cells (f‐PSCs) have attracted great attention because of their unique advantages in lightweight and portable electronics applications. However, their efficiencies are far inferior to those of their rigid counterparts. Herein, a novel histamine diiodate (HADI) is designed based on theoretical study to modify the SnO2/perovskite interface. Systematic experimental results reveal that the HADI serves effectively as a multifunctional agent mainly in three aspects: 1) surface modification to realign the SnO2 conduction band upward to improve interfacial charge extraction; 2) passivating the buried perovskite surface, and 3) bridging between the SnO2 and perovskite layers for effective charge transfer. Consequently, the rigid MA‐free PSCs based on the HADI‐SnO2 electron transport layer (ETL) display not only a high champion power conversion efficiency (PCE) of 24.79% and open‐circuit voltage (VOC) of 1.20 V but also outstanding stability as demonstrated by the PSCs preserving 91% of their initial efficiencies after being exposed to ambient atmosphere for 1200 h without any encapsulation. Furthermore, the solution‐processed HADI‐SnO2 ETL formed at low temperature (100 °C) is utilized in f‐PSCs that achieve a PCE as high as 22.44%, the highest reported PCE for f‐PSCs to date.

Record‐Efficiency Flexible Perovskite Solar Cells Enabled by Multifunctional Organic Ions Interface Passivation

Small-molecular donor guest achieves rigid 18.5% and flexible 15.9% efficiency organic photovoltaic via fine-tuning microstructure morphology

Organic photovoltaics (OPVs) have progressed steadily through three stages of photoactive materials development: (i) use of poly(3-hexylthiophene) and fullerene-based acceptors (FAs) for optimizing bulk heterojunctions; (ii) development of new donors to better match with FAs; (iii) development of non-fullerene acceptors (NFAs). The development and application of NFAs with an A-D-A configuration (where A = acceptor and D = donor) has enabled devices to have efficient charge generation and small energy losses (Eloss < 0.6 eV), resulting in substantially higher power conversion efficiencies (PCEs) than FA-based devices. The discovery of Y6-type acceptors (Y6 = 2,2'-((2Z,2'Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]-thiadiazolo[3,4-e]-thieno[2″,3″:4',5']thieno-[2',3':4,5]pyrrolo-[3,2-g]thieno-[2',3':4,5]thieno-[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) with an A-DA' D-A configuration has further propelled the PCEs to go beyond 15% due to smaller Eloss values (∼0.5 eV) and higher external quantum efficiencies. Subsequently, the PCEs of Y6-series single-junction devices have increased to >19% and may soon approach 20%. This review provides an update of recent progress of OPV in the following aspects: developments of novel NFAs and donors, understanding of the structure-property relationships and underlying mechanisms of state-of-the-art OPVs, and tasks underpinning the commercialization of OPVs, such as device stability, module development, potential applications, and high-throughput manufacturing. Finally, an outlook and prospects section summarizes the remaining challenges for the further development of OPV technology.

Renewed Prospects for Organic Photovoltaics.

Achieving high efficiency and well-kept ductility in ternary all-polymer organic photovoltaic blends thanks to two well miscible donors

Solvent Annealing Enables 15.39% Efficiency All-Small-Molecule Solar Cells through Improved Molecule Interconnection and Reduced Non-Radiative Loss

π-Conjugated Small Molecules Modified SnO2 Layer for Perovskite Solar Cells with over 23% Efficiency

Crumple Durable Ultraflexible Organic Solar Cells with an Excellent Power-per-Weight Performance

The stability of organic solar cells (OSCs) is an urgent problem for commercialization. In this work, a novel asymmetric molecule TB-4Cl was designed and synthesized. Quantum chemical computations ...

Jinsheng Zhang

Papers

Small-molecular donor guest achieves rigid 18.5% and flexible 15.9% efficiency organic photovoltaic via fine-tuning microstructure morphology

Solvent Annealing Enables 15.39% Efficiency All-Small-Molecule Solar Cells through Improved Molecule Interconnection and Reduced Non-Radiative Loss

π-Conjugated Small Molecules Modified SnO2 Layer for Perovskite Solar Cells with over 23% Efficiency

Crumple Durable Ultraflexible Organic Solar Cells with an Excellent Power-per-Weight Performance

High-Efficiency Thermal-Annealing-Free Organic Solar Cells Based on an Asymmetric Acceptor with Improved Thermal and Air Stability.