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Exploiting ternary blends for improved photostability in high efficiency organic solar cells
摘要： Ternary organic solar cells based on polymer donor and nonfullerene acceptors (NFAs) are delivering high power conversion efficiencies (PCE). Now, further improvement needs to be directed to enhance the operational lifetime of organic photovoltaics. Here, we selected three NFAs with different electron affinities and structural properties and found that the most crystalline third component, O-IDTBR, is selectively miscible within the acceptor phase. This reduced trap-assisted recombination and delivered a PCE of 16.6% and a fill factor of 0.76, compared to PM6:Y6 binary devices (15.2% PCE). Charge transport and recombination analyses revealed that O-IDTBR acts as a charge relay for improved charge transfer of both donor and acceptor materials leading to a more ordered transport. We find that minimizing traps formation in ternary devices deactivates light-induced traps upon full sun illumination (AM1.5G). As a result, ternary devices do not show any PCE drop in 225h, in comparison to binary cells which lose more than 60% of their initial performances.
关键词： photostability,nonfullerene acceptors,ternary organic solar cells,power conversion efficiency,charge transport
更新于2025-09-23 15:21:01
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Role of shell composition and morphology in achieving single-emitter photostability for green-emitting a??gianta?? quantum dots
摘要： The use of the varied chemical reactivity of precursors to drive the production of a desired nanocrystal architecture has become a common method to grow thick-shell graded alloy quantum dots (QDs) with robust optical properties. Conclusions on their behavior assume the ideal chemical gradation and uniform particle composition. Here, advanced analytical electron microscopy (high-resolution scanning transmission electron microscopy coupled with energy dispersive spectroscopy) is used to confirm the nature and extent of compositional gradation and these data are compared with performance behavior obtained from single-nanocrystal spectroscopy to elucidate structure, chemical-composition, and optical-property correlations. Specifically, the evolution of the chemical structure and single-nanocrystal luminescence was determined for a time-series of graded-alloy “CdZnSSe/ZnS” core/shell QDs prepared in a single-pot reaction. In a separate step, thick (～6 monolayers) to giant (>14 monolayers) shells of ZnS were added to the alloyed QDs via a successive ionic layer adsorption and reaction (SILAR) process, and the impact of this shell on the optical performance was also assessed. By determining the degree of alloying for each component element on a per-particle basis, we observe that the actual product from the single-pot reaction is less “graded” in Cd and more so in Se than anticipated, with Se extending throughout the structure. The latter suggests much slower Se reaction kinetics than expected or an ability of Se to diffuse away from the initially nucleated core. It was also found that the subsequent growth of thick phase-pure ZnS shells by the SILAR method was required to significantly reduce blinking and photobleaching. However, correlated single-nanocrystal optical characterization and electron microscopy further revealed that these beneficial properties are only achieved if the thick ZnS shell is complete and without large lattice discontinuities. In this way, we identify the necessary structural design features that are required for ideal light emission properties in these green-visible emitting QDs.
关键词： green-emitting,photostability,quantum dots,morphology,giant quantum dots,shell composition
更新于2025-09-23 15:21:01
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Higha??Performance Ternary Organic Solar Cells with Morphologya??Modulated Hole Transfer and Improved Ultraviolet Photostability
摘要： Ternary bulk-heterojunction (BHJ) strategy synergistically combining the merits of fullerene and non-fullerene acceptors has been regarded as a promising approach to enhance the power conversion efficiencies (PCEs) of organic solar cells (OSCs). Herein, the fullerene derivative ICBA as the morphology regulator is incorporated into non-fullerene based PBDB-T-2F:BTP-4Cl (PM6:BTP-4Cl) system to fabricate the high-performance ternary OSCs. The amorphous ICBA prefers to homogeneously distribute in the BTP-4Cl phase to form the well-mixed acceptor domains due to their better miscibility, which distinctly reduces the exciton decay loss driven by the unfavorable phase separation and enhances BHJ morphology stability of ternary blends. The appropriate addition of ICBA induces the efficient long-range F?rster resonance energy transfer to BTP-4Cl and facilitates the ultrafast hole transfer process from BTP-4Cl to PM6, thereby contributing to charge carrier generation in the actual devices. Ultimately, the optimal ternary OSCs not only yield the average PCE higher than 16.5% but also show the superior ultraviolet photostability relative to binary control devices owing to the increased harvesting of ultraviolet photons, boosted charge transfer, more balanced charge transport and more stable nano-structural morphology. Our results provide the new insights to enable the simultaneously improved device performance and tolerance to UV light in highly efficient ternary OSCs.
关键词： hole transfer,non-fullerene,ultraviolet photostability,ternary organic solar cells
更新于2025-09-23 15:19:57
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Robust Polymer Matrix Based on Isobutylene (Co)Polymers for Efficient Encapsulation of Colloidal Semiconductor Nanocrystals
摘要： We introduce new oxygen- and moisture-proof polymer matrices based on polyisobutylene (PIB) and its block copolymer with styrene (poly(styrene-block-isobutylene-block-styrene), PSt-b-PIB-b-PSt) for encapsulation of colloidal semiconductor nanocrystals. In order to prepare transparent and processable composites, we developed a special procedure of the nanocrystal surface engineering including ligand exchange of parental organic ligands to inorganic species followed by attachment of specially designed short-chain PIB functionalized with amino-group (PIB-NH2). The latter provides excellent compatibility of the particles with the polymer matrices. As colloidal nanocrystals, we chose CdSe nanoplatelets (NPLs), since they possess a large surface and thus are very sensitive to the environment, in particular in terms of their limited photostability. The encapsulation strategy is quite general and can be applied to a wide variety of semiconductor nanocrystals, as demonstrated on the example of PbS quantum dots. All obtained composites exhibited excellent photostability being tested in a focus of a powerful white-light source, as well as exceptional chemical stability in a strongly acidic media. We compared these properties of the new composites with those of widely used polyacrylate based materials, demonstrating the superiority of the former. The developed composites are of particular interest for application in optoelectronic devices, such as color-conversion light emitting diodes (LEDs), laser diodes, luminescent solar concentrators, etc.
关键词： photoluminescence,nanocrystals-in-polymer composites,lead sulfide quantum dots,semiconductor nanocrystals,isobutylene (co)polymers,cadmium selenide nanoplatelets,photostability,chemical stability
更新于2025-09-19 17:15:36
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Efficient and Photostable Ternary Organic Solar Cells with a Narrow Bandgap Non-Fullerene Acceptor and Fullerene Additive
摘要： Recent breakthroughs in molecular design have allowed for remarkable achievement in the field of non-fullerene acceptor (NFA)-based organic solar cells (OSCs) with high power conversion efficiencies (PCEs) of over 15%. However, despite such promising advances, the inferior stability of OSCs under operational conditions remains a prominent challenge that must be overcome for their practical realization. Here, versatile ternary photoactive systems with simultaneously enhanced efficiency and photostability are developed by introducing a small amount of fullerene (PC71BM) into a narrow bandgap NFA-based bulk heterojunction nanocomposite (PTB7-Th:IEICO-4F); this approach leads to an enhanced PCE of 10.55% and a prolonged lifetime, retaining approximately 80% of the initial PCEs after 500 h of operation under continuous illumination. Based on the energy levels and surface energies of the component materials, cascade energetic alignment facilitates electron transfer without trapping. The PTB7-Th/PC71BM interface provides an energy barrier to suppress recombination between holes in PTB7-Th and electrons in IEICO-4F. Moreover, a small amount of PC71BM promotes favorable molecular packing and orientation of IEICO-4F, leading to enhanced electron mobility and balanced charge transport. The study on the transient absorption spectroscopy reveals that the ternary blend effectively suppresses the evolution of charge recombination.
关键词： photostability,non-fullerene acceptor,power conversion efficiency,organic solar cells,ternary blend
更新于2025-09-19 17:13:59
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An interlayer with strong Pb-Cl bond delivers ultra-violet-filter-free, efficient and photostable perovskite solar cells
摘要： The inorganic metal oxides (IMOs), including titanium dioxide (TiO2) and tin dioxide (SnO2) inevitably induce decomposition of perovskite under ultra-violet (UV) illumination due to their photocatalytic activity and the use of a UV filter will add extra cost and reduce the effective power output. Here, we firstly reveal that the weak Pb-I bond in I-based perovskite is prone to breakage under UV photocatalysis, leading to serious degradation of SnO2/perovskite interface. We introduce a chlorine-rich mixed-halide perovskite interlayer (ClMPI), which possesses an excellent tolerance to photocatalysis due to the strong Pb-Cl bond, between the SnO2 and I-based perovskite. The ClMPI-based device achieves an enhanced efficiency of up to 21.01% (certified 20.17%). Most importantly, the resultant devices can maintain >94% of their initial performance after 180 h under outdoor solar irradiation, >80% after 500 h under UV irradiation and 500 h under continuous full spectrum illumination at their maximum power points.
关键词： perovskite solar cell,UV-filter-free,photostability,Pb-Cl,photocatalysis
更新于2025-09-19 17:13:59
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Highly Stabilized Gradient Alloy Quantum Dots and Silica Hybrid Nanospheres by Core Double Shells for Photoluminescence Devices
摘要： This Letter reports the synthesis approach and application of colloidal suspensions containing gradient alloy quantum dots (QDs) and silica hybrid spheres with improved thermal and photostability, invisible QD aggregation, and high material compatibility. These hybrid nanospheres are characterized by using silica spheres as cores, adsorbing QDs as one shell, and then coating a silica layer as another shell (termed SiO2?QD?SiO2). They were synthesized by using Sto?ber and adsorption methods. The experimental conditions affecting the optical properties were fully investigated. A light-guiding microstructure array (LGMA) was fabricated and tested for photoluminescence demonstration. After accelerated aging tests for 240 h under 85 °C, 40% relative humidity, and 450 nm blue light excitation, the luminance of the SiO2?QD?SiO2 LGMA remained stable, which was 1.6 times greater than that of untreated QD samples. This structure with long-term photothermal stability could pave the way for displays or lighting applications.
关键词： photostability,photoluminescence,thermal stability,quantum dots,silica hybrid nanospheres
更新于2025-09-19 17:13:59
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Enhanced Lifetime and Photostability with Low-temperature Mesoporous ZnTiO3/Compact SnO2 Electrodes in Perovskite Solar Cells
摘要： Perovskite solar cells (PSC) which have exceeded power conversion efficiencies (PCEs) of 25% are mainly demonstrated by using SnO2 or TiO2 as electron-transporting layers (ETLs). However, high-performance planar PSCs need precise process, which is difficult for large-scale production. Mesoporous structure shows better operability but with high-temperature process. Besides, as the most used mesoporous materials, the strong photocatalytic effect of TiO2 significantly limits the practical stability of PSCs under illumination (including ultraviolet light). Here we propose Zinc Titanate (ZnTiO3, ZTO) as mesoporous ETLs due to its weak photo-effect, excellent carrier extraction and transfer properties. Uniform mesoporous films were obtained by spinning coating the ZTO ink and annealed below 150°C. Photovoltaic devices based on Cs0.05FA0.81MA0.14PbI2.55Br0.45 perovskite sandwiched between SnO2-mesorporous ZTO electrode and Spiro-OMeTAD layer achieved the PCE of 20.5%. The PSCs retained more than 95% of their original efficiency after 100 days lifetime test without being encapsulated. Additionally, the PSCs retained over 95% of the initial performance when subjected at the maximum power point voltage for 120 h under AM 1.5G illumination (100 mW cm-2), demonstrating superior working stability. The application of ZTO provides a better choice for ETLs of PSCs. Moreover, the low temperature deposition method of inorganic ETL furnishes a way of low power consumption, large-scale and flexible preparation of PSCs.
关键词： perovskite solar cell,photostability,ZTO,low-temperature,mesoporous ETL
更新于2025-09-19 17:13:59
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Interface-enhanced organic solar cells with extrapolated T80 lifetimes of over 20 years
摘要： With recent advances in the power conversion efficiency (PCE) of organic solar cells (OSCs) based on novel donor and non-fullerene acceptor (NFAs), improving the stability of these systems has become the most important issue for their practical applications. Herein, an efficient and highly stable OSC, containing a novel polymer donor and a non-fullerene acceptor system, is reported. The OSC is based on an inverted device structure that utilizes a self-assembled fullerene monolayer (C60-SAM) as the cathode modification layer, an efficient and highly stable OSC composes of a polymer donor of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b’]dithiophene-alt-3-fluorothie-n o[3,4-b]thiophene-2-carboxylate] (PTB7-Th) and a non-fullerene acceptor of (2,2'-((2Z,2'Z)-(((4,4,9,9-Tetrakis(4-hexylphenyl)-4,9-dihydro-sindaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(4-((2ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-diflu oro-3-oxo-2,3-dihydro-1H-indene -2,1-diylidene))dimalononitrile) (IEICO-4F) is presented, showing a PCE of 10%. It further achieves an extrapolated T80 lifetime (the time required to reach 80% of initial performance) of 34,000 h, operating under one sun illumination equivalent. Based on an estimated solar irradiance of 1500 kWh/(m2 year) for China, a potential lifetime of 22 years is inferred for the OSC. Further investigation reveals that the reported C60-SAM modification stabilizes the OSC active layer morphology by lowering the surface energy of the underlying ZnO electron transport layer and suppressing trap-assisted recombination, thereby improving photostability. The results of this work establish important guidelines for the development of non-fullerene based OSCs with enhanced stability and pave the way for the commercialization of OSC technology.
关键词： interlayer modification,non-fullerene acceptor,photostability,green solvent,organic solar cell
更新于2025-09-19 17:13:59
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Sustained photodynamic effect of single chirality-enriched single-walled carbon nanotubes
摘要： Semiconducting single-walled carbon nanotubes (s-SWNTs) are capable of fluorescence emission as well as photothermal and photodynamic actions, resulting from their near-infrared (NIR) absorptions corresponding to their S11 and S22 transitions. Here, we show that one chiral s-SWNTs, (6,4)-SWNTs, photogenerates all three of the major reactive oxygen species, i.e., singlet oxygen (1O2), superoxide anion (O2?–), and hydroxyl radical (?OH), in a sustainable manner. Its efficiency for ?OH generation is dramatically higher than those of the other two chiral s-SWNTs tested, as well as a clinical NIR dye. This sustained and relatively high photodynamic effect in (6,4)-SWNTs is due to their extraordinary high photostability and relatively high generation efficiency of their triplet excited state. In the colloidal stabilization of (6,4)-SWNTs under physiological conditions, a serum protein consisting of a tandem repeat of amphiphilic a -helices is found to be useful for dispersion. The protein-coated (6,4)-SWNTs are capable of effectively ablating cancer cells and disintegrating amyloid beta peptide aggregates through sustained photodynamic action.
关键词： Single-walled carbon nanotubes,Photodynamic effect,Cancer therapy,Reactive oxygen species,Photostability,Amyloid beta peptide
更新于2025-09-19 17:13:59