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

Following the 2nd release of the “Emerging PV reports,” the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer‐reviewed articles in academic journals since August 2021. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open‐circuit voltage, short‐circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application, and are put into perspective using, e.g., the detailed balance efficiency limit. The 3rd installment of the “Emerging PV reports” extends the scope toward triple junction solar cells.

Device Performance of Emerging Photovoltaic Materials (Version 3)

High-Performance Ternary Organic Solar Cells through Incorporation of a Series of A2-A1-D-A1-A2 Type Nonfullerene Acceptors with Different Terminal Groups

High-performance organic photovoltaic modules using eco-friendly solvents for various indoor application scenarios

With the emergence of ADA'DA‐type (Y‐series) non‐fullerene acceptors (NFAs), the power conversion efficiencies (PCEs) of organic photovoltaic devices have been constantly refreshed and gradually reached 20% in recent years (19% for single junction and 20% for tandem device). The acceptors possess specific design concept, which greatly enrich the NFA types and have excellent compatibility with many donor materials. It is gratifying to note that the previously underperforming donor materials combine with these regulated acceptors to shine again. Nowadays, the concept of modular design is widely used in the research of acceptors and donors, injecting new vitality into the field of organic photovoltaics. Furthermore, these acceptors also promote the research of multicomponent devices, tandem devices, bilayer devices, processing solvent engineering, and additive engineering. Herein, the latest progresses of polymer solar cells with efficiency over 17% are briefly reviewed from the aspects of active material design, interface material development, and device technology. At last, the opportunities and challenges of organic photovoltaic commercialization in the future are discussed.

Recent Developments of Polymer Solar Cells with Photovoltaic Performance over 17%

Ternary strategy has been identified as a feasible and effective way to obtain high-efficiency organic solar cells (OSCs). However, for most ternary OSCs, the voltage loss (Vloss) lies between those...

Ternary Strategy Enabling High-Efficiency Rigid and Flexible Organic Solar Cells with Reduced Non-radiative Voltage Loss

In this study, copolymer of poly (aniline-co-pyrrole) (P(ANI-co-Py)) was synthesized through copolymerization with (NH4)2S2O8 (APS) as oxidizing agent. Au nanoparticles (NPs) were deposited on P(ANI-co-Py) through the Au sol adsorption technique to obtain Au/P(ANI-co-Py) catalysts. For comparison, Au/PPy and Au/PANI were also prepared under the same procedure. The samples were characterized by SEM, TEM, XPS, N2 adsorption/desorption, XRD and FT-IR. Results imply that the P(ANI-co-Py) can be successfully prepared and can stabilize the small Au NPs with highly dispersed state. As expected, the Au/P(ANI-co-Py) catalysts, especially Au/P(5ANI-co-Py5), show efficient performance compared with Au/PANI and Au/PPy in 4-nitrophenol (4-NP) reduction. The outstanding catalytic activities of Au/P(5ANI-co-5Py) can be ascribed to well dispersed Au NPs, strong electronic metal-support interaction (EMSI), an appropriate adsorption of 4-NP and the negatively charged Au NPs surface. This work offers a facile method to provide conductive polymers supported Au catalysts with high catalytic performance and excellent reusability and clarifies their potential applications in industrial wastewater treatment. 

Gold nanoparticles supported on poly (aniline-co-pyrrole) as the efficient catalysts for the reduction of 4-nitrophenol

Abstract Friction modifiers (FMs) are surface-active additives added to base fluids to reduce friction between rubbing surfaces. Their effectiveness depends on their interactions with rubbing surfaces and may be mitigated by the choice of the base fluid. In this work, the performance of an imidazolium ionic liquid (ImIL) additive in polyethylene-glycol (PEG) and 1,4-butanediol for lubricating steel/steel and diamond-like-carbon/diamond-like carbon (DLC—DLC) contacts were investigated. ImIL-containing PEG reduces friction more effectively in steel—steel than DLC—DLC contacts. In contrast, adding ImIL in 1,4-butanediol results in an increase in friction in steel—steel contacts. Results from the Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and focused ion beam-transmission electron microscopy (FIB-TEM) reveal that a surface film is formed on steel during rubbing in ImIL-containing PEG. This film consists of two layers. The top layer is composed of amorphous carbon and are easily removed during rubbing. The bottom layer, which contains iron oxide and nitride compound, adheres strongly on the steel surface. This film maintains its effectiveness in a steel—steel contact even after ImIL additives are depleted. Such film is not observed in 1,4-butanediol where the adsorption of ImIL is hindered, as suggested by the quartz crystal microbalance (QCM) measurements. No benefit is observed when the base fluid on its own is sufficiently lubricious, as in the case of DLC surfaces. This work provides fundamental insights on how compatibilities among base fluid, FM, and rubbing surface affect the performance of IL as surface active additives. It reveals the structure of an ionic liquid (IL) surface film, which is effective and durable. The knowledge is useful for guiding future IL additive development. 

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Wei Song

Papers

Ternary Strategy Enabling High-Efficiency Rigid and Flexible Organic Solar Cells with Reduced Non-radiative Voltage Loss

Gold nanoparticles supported on poly (aniline-co-pyrrole) as the efficient catalysts for the reduction of 4-nitrophenol

Lubrication mechanism of a strong tribofilm by imidazolium ionic liquid