Low energy loss and efficient charge separation under small driving forces are the prerequisites for realizing high power conversion efficiency (PCE) in organic photovoltaics (OPVs). Here, a new ...molecular design of nonfullerene acceptors (NFAs) is proposed to address above two issues simultaneously by introducing asymmetric terminals. Two NFAs, BTP‐S1 and BTP‐S2, are constructed by introducing halogenated indandione (A1) and 3‐dicyanomethylene‐1‐indanone (A2) as two different conjugated terminals on the central fused core (D), wherein they share the same backbone as well‐known NFA Y6, but at different terminals. Such asymmetric NFAs with A1‐D‐A2 structure exhibit superior photovoltaic properties when blended with polymer donor PM6. Energy loss analysis reveals that asymmetric molecule BTP‐S2 with six chlorine atoms attached at the terminals enables the corresponding devices to give an outstanding electroluminescence quantum efficiency of 2.3 × 10−2%, one order of magnitude higher than devices based on symmetric Y6 (4.4 × 10−3%), thus significantly lowering the nonradiative loss and energy loss of the corresponding devices. Besides, asymmetric BTP‐S1 and BTP‐S2 with multiple halogen atoms at the terminals exhibit fast hole transfer to the donor PM6. As a result, OPVs based on the PM6:BTP‐S2 blend realize a PCE of 16.37%, higher than that (15.79%) of PM6:Y6‐based OPVs. A further optimization of the ternary blend (PM6:Y6:BTP‐S2) results in a best PCE of 17.43%, which is among the highest efficiencies for single‐junction OPVs. This work provides an effective approach to simultaneously lower the energy loss and promote the charge separation of OPVs by molecular design strategy.
Asymmetric electron acceptors, by combining halogenated indandione and 3‐dicyanomethylene‐1‐indanone as two different conjugated terminals, are designed and synthesized. Such design enables reduced energy loss and boosts charge separation, thus leading to 16.37% binary organic photovoltaics (OPVs) and 17.43% ternary OPVs, which are among the best efficiencies for single‐junction OPVs.
Organic photovoltaic cells (OPVs) have attracted broad attention and become a very energetic field after the emergence of nonfullerene acceptors. Long‐lifetime triplet excitons are expected to be ...good candidates for efficiently harvesting a photocurrent. Parallel with the development of OPVs based on singlet materials (S‐OPVs), the potential of triplet materials as photoactive layers has been explored. However, so far, OPVs employing triplet materials in a bulk heterojunction have not exhibited better performance than S‐OPVs. Here, the recent progress of representative OPVs based on triplet materials (T‐OPVs) is briefly summarized. Based on that, the performance limitations of T‐OPVs are analyzed. The shortage of desired triplet materials with favorable optoelectronic properties for OPVs, the tradeoff between long lifetime and high binding energy of triplet excitons, as well as the low charge mobility in most triplet materials are crucial issues restraining the efficiencies of T‐OPVs. To overcome these limitations, first, novel materials with desired optoelectronic properties are urgently demanded; second, systematic investigation on the contribution and dynamics of triplet excitons in T‐OPVs is necessary; third, close multidisciplinary collaboration is required, as proved by the development of S‐OPVs.
To harvest a large photocurrent in bulk‐heterojunction organic photovoltaic cells (OPVs), materials with long‐lifetime triplet excitons are expected to be potential candidates for providing sufficient time for diffusion of excitons to donor/acceptor interfaces. Recent progress of various triplet‐material‐based OPVs (T‐OPVs) is briefly summarized, and performance limitations and strategies to further enhance the performance of T‐OPVs are discussed.
PEDOT is the most popularly used conductive polymer due to its high conductivity, good physical and chemical stability, excellent optical transparency, and the capabilities of easy doping and ...solution processing. Based on the advantages above, PEDOT has been widely used in various devices for energy conversion and storage, and bio-sensing. The synthesis method of PEDOT is very important as it brings different properties which determine its applications. In this mini review, we begin with a brief overview of recent researches in PEDOT. Then, the synthesis methods of PEDOT are summarized in detail, including chemical polymerization, electrochemical polymerization, and transition metal-mediated coupling polymerization. Finally, research directions in acquiring high-quality PEDOT are discussed and proposed.
To analyze the predictive value of hyperglycemia on the extrapancreatic infection (EPI) and infected pancreatic necrosis (IPN) of severe patients with acute pancreatitis (AP). We enrolled 234 ...patients with acute pancreatitis admitted to the intensive care unit (ICU) of the Second Affiliated Hospital of Nanchang University from July 2017 to July 2022 for a retrospective cohort study. We collected maximum blood glucose values three times after admission to the ICU within 120 h (Glu1: 0-24 h, Glu2: 24-48 h, Glu3: 48-120 h), the levels of leucocyte, blood urea nitrogen (BUN), C-reactive protein (CRP), procalcitonin (PCT), and albumin within 24 h after admission to the ICU, and the BISAP and SIRS scores of all patients within 24 h. EPI was taken as the primary outcome indicator and IPN as the secondary outcome indicator. The accuracy of blood glucose values in predicting acute pancreatitis infection was measured by the area under the curve (AUC). A total of 56 patients appeared EPI. Univariate analysis showed that Glu3 was associated with IPN in critically ill patients with AP. Multivariate logistic regression analysis showed that Glu2, Glu3, and SIRS > 48 h were associated with EPI in critically ill patients with AP. The AUCs of Glu2 and Glu3 to predict EPI were 0.805(95%CI: 0.717-0.892) and 0.782(95%CI: 0.685-0.878), respectively, and the cutoff values were 12.60 mmol/L and 14.75 mmol/L, respectively. The AUC of Glu2 combined with Glu3 to predict EPI was 0.812(0.725-0.899). The maximum blood glucose on Day2-5 after admission to the ICU can predict infection in critically ill patients with AP. There are differences in etiology while glucose predicting infection. Patients with hypertriglyceridemia AP need to intervene blood glucose levels more actively and earlier, and control it more strictly.
Abstract
We explored the application value of bedside ultrasound dynamic monitoring of the inferior vena cava diameter (IVCD) and collapse with sniff (inferior vena cava collapsibility index IVCCI) ...to guide dehydration adjustment in continuous renal replacement therapy (CRRT) in patients with combined renal failure and acute heart failure. We selected 90 patients with combined renal and acute heart failure who required CRRT in the intensive care unit (ICU) from January 2019 to June 2021. According to different blood volume assessment methods, patients were randomly divided into ultrasound, experience, and control groups. We compared serum creatinine, potassium, and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels; time to improved heart failure symptoms; CRRT time; ventilator use; ICU length of stay; vasopressor use; and incidence of adverse events among groups. There were no significant differences in serum creatinine, potassium, and NT-proBNP levels in pairwise comparisons among groups before and after CRRT (P > 0.05). The time to improved heart failure symptoms, CRRT time, and ICU length of stay in the ultrasound and experience groups were lower than those in the control group; the differences were statistically significant (P < 0.05). Ventilator use duration was lower in the ultrasound and experience groups compared with the control group, with a statistically significant difference between the ultrasound and control groups (P < 0.05). The duration of vasopressor use in the ultrasound and control groups was lower than that in the experience group; the difference was statistically significant (P < 0.05). The incidence of adverse events was lower in the ultrasound group compared with the experience and control groups; the difference was statistically significant (P < 0.05). Ultrasound dynamic monitoring of IVCD and collapse with sniff can accurately assess blood volume status, and provide guidance for dehydration adjustments in CRRT and rapid relief of heart failure symptoms in patients with combined renal and acute heart failure.
Plastic electrodes are desirable for the rapid development of flexible organic electronics. In this article, a plastic electrode has been prepared by employing traditional conducting polymer ...poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and plastic substrate polyethersulfone (PES). The completed electrode (Denote as HC-PEDOT:PSS) treated by 80% concentrated sulfuric acid (H
SO
) possesses a high electrical conductivity of over 2673 S/cm and a high transmittance of over 90% at 550 nm. The high conductivity is attributed to the regular arrangement of PEDOT molecules, which has been proved by the X-ray diffraction characterization. Temperature-dependent conductivity measurement reveals that the HC-PEDOT:PSS possesses both semiconducting and metallic properties. The binding force and effects between the PEDOT and PEI are investigated in detail. All plastic solar cells with a classical device structure of PES/HC-PEDOT:PSS/PEI/P3HT:ICBA/EG-PEDOT:PSS show a PCE of 4.05%. The ITO-free device with a structure of Glass/HC-PEDOT:PSS/Al4083/PM6:Y6/PDINO/Ag delivers an open-circuit voltage (
) of 0.81 V, short-circuit current (
) of 23.5 mA/cm
, fill factor (FF) of 0.67 and a moderate power conversion efficiency (PCE) of 12.8%. The above results demonstrate the HC-PEDOT:PSS electrode is a promising candidate for all-plastic solar cells and ITO-free organic solar cells.
In this work, we developed four porphyrin-based small molecular electron acceptors for non-fullerene organic solar cells, in which different side groups attached to the porphyrin core were selected ...in order to achieve optimized performance. The molecules contain porphyrin as the core, perylene bisimides as end groups, and the ethynyl unit as the linker. Four side groups, from 2,6-di(dodecyloxy)phenyl to (2-ethylhexyl)thiophen-2-yl, pentadecan-7-yl, and 3,5-di(dodecyloxy)phenyl unit, were applied into the electron acceptors. The new molecules exhibit broad absorption spectra from 300 to 900 nm and high molar extinction coefficients. The molecules as electron acceptors were applied into organic solar cells, showing increased power conversion efficiencies from 1.84 to 5.34%. We employed several techniques, including photoluminescence spectra, electroluminescence spectra, atomic force microscopy, and grazing-incidence wide-angle X-ray to probe the blends to find the effects of the side groups on the photovoltaic properties. We found that the electron acceptors with 2,6-di(dodecyloxy)phenyl units show high-lying frontier energy levels, good crystalline properties, and low nonradiative recombination loss, resulting in possible large phase separation and low energy loss, which is responsible for the low performance. Our results provide a detailed study about the side groups of non-fullerene materials, demonstrating that porphyrin can be used to design electron acceptors toward near-infrared absorption.
With the growing popularity of portable and wearable smart electronics, the electromagnetic shielding materials with high shielding effectiveness (SE) as well as light weight and excellent mechanical ...strength are in high. In this work, the PEDOT:PSS‐based free‐standing conducting film with superior conductivity and mechanical strength is prepared through a facile fabrication. The cellulose nanofibers (CNFs) are first introduced to induce an orderly grow and stack of the PEDOT grains. A phosphoric acid immersion process is then employed to remove the insulating CNF and PSS in the film. The obtained free‐standing conducting film shows a record conductivity of 3508 S cm−1 and its elongation at break reaches 3.75%. Encouragingly, the film delivers an excellent electromagnetic interference (EMI) shielding behavior with a SE of 49 dB in the X‐band (8.2–12.4 GHz) at a thickness of 4 µm. The superior conductivity, mechanical strength, and high SE as well as its facile solution processability make this free‐standing conducting film to be an attractive EMI material for portable and wearable smart electronics.
A densely packed free‐standing PEDOT:PSS film with superior conductivity and mechanical strength is prepared. The free‐standing film exhibits an excellent electromagnetic interference shielding behavior with a shielding effectiveness of 49 dB in the X‐band and is envisioned to bwoven into clothing to protect the human body from electromagnetic damage.
A free‐standing high‐output power density polymeric thermoelectric (TE) device is realized based on a highly conductive (≈2500 S cm−1) structure‐ordered poly(3,4‐ethylenedioxythiophene):polystyrene ...sulfonate film (denoted as FS‐PEDOT:PSS) with a Seebeck coefficient of 20.6 µV K−1, an in‐plane thermal conductivity of 0.64 W m−1 K−1, and a peak power factor of 107 µW K−2 m−1 at room temperature. Under a small temperature gradient of 29 K, the TE device demonstrates a maximum output power density of 99 ± 18.7 µW cm−2, which is the highest value achieved in pristine PEDOT:PSS based TE devices. In addition, a fivefold output power is demonstrated by series connecting five devices into a flexible thermoelectric module. The simplicity of assembling the films into flexible thermoelectric modules, the low out‐of‐plane thermal conductivity of 0.27 W m−1 K−1, and free‐standing feature indicates the potential to integrate the FS‐PEDOT:PSS TE modules with textiles to power wearable electronics by harvesting human body's heat. In addition to the high power factor, the high thermal stability of the FS‐PEDOT:PSS films up to 250 °C is confirmed by in situ temperature‐dependent X‐ray diffraction and grazing incident wide angle X‐ray scattering, which makes the FS‐PEDOT:PSS films promising candidates for thermoelectric applications.
A free‐standing thermoelectric (TE) device is realized based on a high conductivity (2500 S cm−1) structure‐ordered poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) film with output power density of 99 ± 18.7 µW cm−2 under a gradient of 29 K, which is the highest value for pure PEDOT:PSS‐based TE device. Free‐standing TE device presented here suggests its great potential application in low‐consumption wearable electronics.
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