The development of conjugated alternating donor–acceptor (D–A) copolymers with various electron‐rich and electron‐deficient units in polymer backbones has boosted the power conversion efficiency ...(PCE) over 17% for polymer solar cells (PSCs) over the past two decades. However, further enhancements in PCEs for PSCs are still imperative to compensate their imperfect stability for fulfilling practical applications. Meanwhile development of these alternating D–A copolymers is highly demanding in creative design and syntheses of novel D and/or A monomers. In this regard, when being possible to adopt an existing monomer unit as a third component from its libraries, either a D′ unit or an A′ moiety, to the parent D–A type polymer backbones to afford conjugated D–A terpolymers, it will give a facile and cost‐effective method to improve their light absorption and tune energy levels and also interchain packing synergistically. Moreover, the rationally controlled stoichiometry for these components in such terpolymers also provides access for further fine‐tuning these factors, thus resulting in high‐performance PSCs. Herein, based on their unique features, the recent progress of conjugated D–A terpolymers for efficient PSCs is reviewed and it is discussed how these factors influence their photovoltaic performance, for providing useful guidelines to design new terpolymers toward high‐efficiency PSCs.
In contrast to conjugated donaor–acceptor (D–A) alternating copolymers, incorporating a third component, either D′‐ or A′‐unit, to their D–A type polymer backbones can improve their light absorption, and tune energy levels and interchain packing synergistically. Moreover, the well‐controlled stoichiometry for these components in terpolymers also provides further access to fine‐tune these factors, thus resulting in high photovoltaic performance in polymer solar cells.
All‐polymer solar cells (all‐PSCs) based on n‐ and p‐type polymers have emerged as promising alternatives to fullerene‐based solar cells due to their unique advantages such as good chemical and ...electronic adjustability, and better thermal and photochemical stabilities. Rapid advances have been made in the development of n‐type polymers consisting of various electron acceptor units for all‐PSCs. So far, more than 200 n‐type polymer acceptors have been reported. In the last seven years, the power conversion efficiency (PCE) of all‐PSCs rapidly increased and has now surpassed 10%, meaning they are approaching the performance of state‐of‐the‐art solar cells using fullerene derivatives as acceptors. This review discusses the design criteria, synthesis, and structure–property relationships of n‐type polymers that have been used in all‐PSCs. Additionally, it highlights the recent progress toward photovoltaic performance enhancement of binary, ternary, and tandem all‐PSCs. Finally, the challenges and prospects for further development of all‐PSCs are briefly considered.
The rapid development of n‐type polymers has boosted the efficiency of all‐polymer solar cells, which has improved from 2% to 10% in only seven years. There is a strong need to summarize the design criteria, synthesis, structure–property relationships and recent advances of n‐type polymers, which is addressed in this review. Moreover, the challenges and prospects for further development of all‐PSCs are briefly discussed.
Driven by the potential advantages and promising applications of organic solar cells, donor‐acceptor (D‐A) polymers have been intensively investigated in the past years. One of the strong ...electron‐withdrawing groups that were widely used as acceptors for the construction of D‐A polymers for applications in polymer solar cells and FETs is isoindigo. The isoindigo‐based polymer solar cells have reached efficiencies up to ∼7% and hole mobilities as high as 3.62 cm2 V−1 s−1 have been realized by FETs based on isoindigo polymers. Over one hundred isoindigo‐based small molecules and polymers have been developed in only three years. This review is an attempt to summarize the structures and properties of the isoindigo‐based polymers and small molecules that have been reported in the literature since their inception in 2010. Focus has been given only to the syntheses and device performances of those polymers and small molecules that were designed for use in solar cells and FETs. Attempt has been made to deduce structure‐property relationships that would guide the design of isoindigo‐based materials. It is expected that this review will present useful guidelines for the design of efficient isoindigo‐based materials for applications in solar cells and FETs.
This review summarizes isoindigobased polymers and small molecules for bulk‐heterojunction solar cells and field‐effect transistors (FETs). The structure‐property relationships are deduced based on results from the literature and density functional theory (DFT) calculations. Isoindigo‐based materials are anticipated to play an important role in the development of solar cells and FETs due to their appropriate energy levels, high absorption coefficients, and mobility.
Growing interests have been devoted to the design of polymer acceptors as potential replacement for fullerene derivatives for high-performance all polymer solar cells (all-PSCs). One key factor that ...is limiting the efficiency of all-PSCs is the low fill factor (FF) (normally <0.65), which is strongly correlated with the mobility and film morphology of polymer:polymer blends. In this work, we find a facile method to modulate the crystallinity of the well-known naphthalene diimide (NDI) based polymer N2200, by replacing a certain amount of bithiophene (2T) units in the N2200 backbone by single thiophene (T) units and synthesizing a series of random polymers PNDI-Tx, where x is the percentage of the single T. The acceptor PNDI-T10 is properly miscible with the low band gap donor polymer PTB7-Th, and the nanostructured blend promotes efficient exciton dissociation and charge transport. Solvent annealing (SA) enables higher hole and electron mobilities, and further suppresses the bimolecular recombination. As expected, the PTB7-Th:PNDI-T10 solar cells attain a high PCE of 7.6%, which is a 2-fold increase compared to that of PTB7-Th:N2200 solar cells. The FF of 0.71 reaches the highest value among all-PSCs to date. Our work demonstrates a rational design for fine-tuned crystallinity of polymer acceptors, and reveals the high potential of all-PSCs through structure and morphology engineering of semicrystalline polymer:polymer blends.
A non‐conjugated polymer acceptor PF1‐TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated ...polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient >105 cm−1, a high LUMO level of −3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1‐TS4‐based all‐PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is ≈45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1‐TS4‐based all‐PSC has good thermal stability with ≈70 % of its initial PCE retained after being stored at 85 °C for 180 h, while the IDIC16‐based device only retained ≈50 % of its initial PCE when stored at 85 °C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non‐conjugated thioalkyl segments.
An efficient non‐conjugated polymer acceptor PF1‐TS4 was developed by embedding thioalkyl linkages in the mainchain of a conjugated polymer. The resulting all‐polymer solar cells achieved a promising device efficiency of 8.63 % with excellent thermal stability at 85 °C for 180 hours.
Integration of a third component into a single-junction polymer solar cell (PSC) is regarded as an attractive strategy to enhance the performance of PSCs. Although binary all-polymer solar cells ...(all-PSCs) have recently emerged with compelling power conversion efficiencies (PCEs), the PCEs of ternary all-PSCs still lag behind those of the state-of-the-art binary all-PSCs, and the advantages of ternary systems are not fully exploited. In this work, we realize high-performance ternary all-PSCs with record-breaking PCEs of 9% and high fill factors (FF) of over 0.7 for both conventional and inverted devices. The improved photovoltaic performance benefits from the synergistic effects of extended absorption, more efficient charge generation, optimal polymer orientations and suppressed recombination losses compared to the binary all-PSCs, as evidenced by a set of experimental techniques. The results provide new insights for developing high-performance ternary all-PSCs by choosing appropriate donor and acceptor polymers to overcome limitations in absorption, by affording good miscibility, and by benefiting from charge and energy transfer mechanisms for efficient charge generation.
High performance solar cells fabricated from an easily synthesized donor‐acceptor polymer show maximum power point up to 6.0 mW cm−2, with an open‐circuit voltage of 0.89 V, short‐circuit current ...density of 10.5 mA cm−2 and fill factor of 0.64, making this polymer a particularly promising candidate for high‐efficiency low‐cost polymer solar cells.
A new, low-band-gap alternating copolymer consisting of terthiophene and isoindigo has been designed and synthesized. Solar cells based on this polymer and PC71BM show a power conversion efficiency ...of 6.3%, which is a record for polymer solar cells based on a polymer with an optical band gap below 1.5 eV. This work demonstrates the great potential of isoindigo moieties as electron-deficient units for building donor–acceptor-type polymers for high-performance polymer solar cells.
Intravital imaging of mouse embryos Huang, Qiang; Cohen, Malkiel A; Alsina, Fernando C ...
Science,
04/2020, Letnik:
368, Številka:
6487
Journal Article
Recenzirano
Odprti dostop
Embryonic development is a complex process that is unamenable to direct observation. In this study, we implanted a window to the mouse uterus to visualize the developing embryo from embryonic day 9.5 ...to birth. This removable intravital window allowed manipulation and high-resolution imaging. In live mouse embryos, we observed transient neurotransmission and early vascularization of neural crest cell (NCC)-derived perivascular cells in the brain, autophagy in the retina, viral gene delivery, and chemical diffusion through the placenta. We combined the imaging window with in utero electroporation to label and track cell division and movement within embryos and observed that clusters of mouse NCC-derived cells expanded in interspecies chimeras, whereas adjacent human donor NCC-derived cells shrank. This technique can be combined with various tissue manipulation and microscopy methods to study the processes of development at unprecedented spatiotemporal resolution.
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