In the past few decades, polymer solar cells (PSCs) have been intensively investigated in academic fields. The study of non-fullerene polymer acceptors has become a hot research focus due to their ...excellent opto-electronic properties such as wide light-absorbing ability, appropriate molecular energy levels, and easy chemical modifications. The much higher power conversion efficiencies (PCEs) of non-fullerene PSCs relative to fullerene PSCs revealed the significant potential of non-fullerene acceptors in PSCs. This review systematically summarizes the recent advancements of efficient polymer acceptors, including perylene diimide-based, naphthalene diimide-based, diketopyrrolopyrrole-based, double B←N bridged bipyridyl-based, and other polymer acceptors. Their structure-property relationships were thoroughly analyzed and summarized, which may provide new guidance for the rational structural design of high-performance photovoltaic materials.
Recent advances in polymer acceptors that focus on structure-property relationships, which may provide guidance for photovoltaic materials, were systematically summarized.
To obtain a polymer based on benzodithiophene (BDT) owning both a largely extended π-conjugation system and a low-lying highest occupied molecular orbital (HOMO), a polymer (PBDTBzT-DTffBT) ...containing benzothienyl-substituted BDT is designed and synthesized. Compared with the polymer (PBDTT-DTffBT) based on thienyl-substituted BDT, PBDTBzT-DTffBT exhibits better thermal stabilities, red-shifted absorption spectra, and stronger intermolecular interactions. The HOMO and lowest unoccupied molecular orbital (LUMO) in PBDTBzT-DTffBT are decreased by 0.11 and 0.13 eV, respectively, which should be attributed to the contribution of the electron-withdrawing group benzene. Polymer solar cells (PSCs) based on PBDTBzT-DTffBT and 6,6-phenyl-C61-butyric acid methyl ester (PC61BM) exhibit a maximum power conversion efficiency (PCE) of 7.30% with a large open-circuit voltage of 0.90 V under AM 1.5G illumination (100 mW/cm2). The PCE is 36% higher than that of the PSCs derived from PBDTT-DTffBT. These findings provide a new approach to design high-performance conjugated polymers for efficient solution-processed PSCs.
Luminescent materials are of worldwide interest because of their unique optical properties. Silica, which is transparent to light, is an ideal matrix for luminescent materials. Luminescent silica ...nanoparticles (LSNs) have broad applications because of their enhanced chemical and thermal stability. Silica spheres of various sizes could be synthesized by different methods to satisfy specific requirements. Diverse luminescent dyes have potential for different applications. Subject to many factors such as quenchers, their performance was not quite satisfying. This review thus discusses the development of LSNs including their classification, synthesis, and application. It is the highlight that how silica improves the properties of luminescent dye and what role silica plays in the system. Further, their applications in biology, display, and sensors are also described.
To clearly show how important the impact of side chains on organic solar cells (OSCs) is, we designed three acceptors IDIC-CxPh (x = 4, 5, or 6) via subtle side-chain regulation. Despite this small ...change, significant distinctions were detected. IDIC-C4Ph devices achieve an optimal efficiency of 13.94% under thermal annealing, but thermal-assistant solvent-vapor annealing hugely suppresses the efficiencies to 10%. However, the C6Ph side chain endows extremely disordered stacking orientations, generating moderate efficiencies of ~12.50%. Excitingly, the IDIC-C5Ph affords an unexpected two-channel π-π charge transport (TCCT) property, boosting the fill factor (FF) by up to 80.02% and efficiency to 14.56%, ranking the best among five-ring fused-ladder-type acceptors. Impressively, the special TCCT behavior of IDIC-C5Ph enables 470 nm thick-film OSC with a high FF of up to 70.12% and efficiency of 13.01%, demonstrating the great promise in fabricating large-scale OSCs.
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•OSCs are a promising technology to transform the solar energy to electricity•This article reports an efficient TCCT photovoltaic material through subtle side-chain modification•The TCCT property enables 13% efficiency with FF reaching 70% in 470 nm thick-film photovoltaics
In this research contribution, the primary objective was to enhance the crystallization behavior of poly(ethylene terephthalate) (PET). To accomplish this tack, three kinds of new nucleating agents ...SiO₂-diethylene glycol-LMPET (PET-3), SiO₂-triethylene glycol-LMPET(PET-4) and SiO₂-tetraethylene glycol-LMPET (PET-5) nucleating agents were prepared via grafting different oligomers (diethylene glycol; triethylene glycol and tetraethylene glycol) to the surface of nano-SiO₂ and then linking to the low molecular weight poly(ethylene terephthalate) (LMPET). These nano-particle nucleating agents facilitated the crystallization of PET. Differential scanning calorimetry (DSC) studies of the composites that pure PET blended with PET-3, PET-4 and PET-5 indicated that the longer ethoxy segment in the nucleating agents exhibited (i) higher degrees of crystallinity; (ii) faster rates of crystallization; and (iii) higher crystallization temperatures. The Jeziorny method was employed to analyze the non-isothermal crystallization kinetics of the composites. These works demonstrated that the PET-3, PET-4 and PET-5 were attractive nucleating agents for poly(ethylene terephthalate), and the longer the chain length of the ethoxy segment in the nucleating agents, the more efficient the nucleation effect.
Achieving multi-color luminescence with a single atomic center in transition metal complexes is a challenge. In this work, luminescent materials with tunable emission properties were realized by ...complexation between aluminum (III) ions with the ligands 3-hydroxyflavone (3-HF) and 5,7-dichloro-8-hydroxyquinoline (DCHQ). Aluminum (III) complexes with a single ligand emitted blue from 3-HF and green from DCHQ. High quantum yields (QYs) of 29.42% and 37.00% were also obtained, respectively. DFT calculations revealed details of the photophysical properties of the complexes. Correspondingly, cyan light emission was obtained if these two complexes were mixed together, from which the emission wavelength was located at 470 nm and the QY was 20.52%, under 290 nm excitation. More importantly, the cyan light emitted by the mixtures had selective sensitivity to different metal ions, resulting in either quenching the fluorescence (in the case of Fe3+) or enhancing the fluorescence (in the case of In3+). The fluorescence enhancement effect of In3+ on metal complexes has not been previously reported, neither for transition metal nor lanthanide ions. The linear quenching behavior of Fe3+ functions in the 50–700 μM concentration range, and the linear enhancement behavior of In3+ is demonstrated in the 300–800 mM concentration range.
Thiadiazolo3,4-cpyridine (PT) has great potential in the construction of high-performance narrow bandgap (NBG) photovoltaic polymers. But to date the best power conversion efficiencies (PCEs) for ...PT-containing polymers are only around 6%. Herein, we report two PT-containing NBG polymers PDTPT-2T and PDTPT-2TF based on 2,2'-bithiophene (2T) and 3,3'-difluoro-2,2'-bithiophene (2TF), respectively. The effects of a fluorine substituent on optoelectronic properties are thoroughly investigated. The film absorption onset of PDTPT-2TF is 855 nm, bathochromic-shifted by 24 nm in comparison with that (831 nm) of PDTPT-2T. The lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels of PDTPT-2TF are down-shifted by 0.15 and 0.11 eV relative to those of PDTPT-2T, respectively. X-ray diffraction (XRD) patterns indicate that a more ordered structure is formed in the solid film of PDTPT-2TF. Furthermore, the miscibility between the polymer and 6,6-phenyl-C71-butyric acid methyl ester (PC71BM) is significantly improved through the introduction of fluorine. Consequently, PDTPT-2TF exhibits a high PCE of 8.01%, while PDTPT-2T only shows a maximum PCE of 2.65%. The efficiency of 8.01% is the highest one for PT-containing polymers, and more importantly, it is achieved without any processing additives or post-treatments. This work indicates that PT would have great potential as a building block to construct high-performance photovoltaic polymers.
The past decade has seen a tremendous development of organic solar cells (OSCs). To date, high-performance OSCs have boosted power conversion efficiencies (PCEs) over 17%, showing bright prospects ...toward commercial applications. Compared with binary OSCs, ternary OSCs, by introducing a third component as a second donor or acceptor into the active layer, have great potential in realizing outstanding photovoltaic performance. Herein, a comprehensive review of the recent advances of ternary solar cells is presented. According to the chemical components of active layer materials, we classify the ternary systems into four categories, including polymer/small molecule/small molecule, polymer/polymer/small molecule, all-polymer and all-small-molecule types. The relationships among the photovoltaic materials structure and weight ratio, active layer morphology and photovoltaic performance are systematically analyzed and summarized. The features and design strategies of each category are also discussed and summarized. Key issues and challenges faced in ternary OSCs are pointed out, and potential strategies and solutions are proposed. This review may provide guidance for the field of ternary OSCs.
This work presents a complete summary of recent advances in ternary organic solar cells, highlighting the relationships among the molecular structure, component weight ratio, active layer morphology and photovoltaic performance.
Black phosphorous quantum dots are used as the interlayer to modify the hole transport layer in organic solar cells. The power conversion efficiencies of the fullerene and non-fullerene devices are ...both improved.
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•Black phosphorus quantum dots possess ultrahigh mobility and tunable direct bandgap.•Black phosphorus quantum dots can improve polymer solar cells by forming better energy alignment.•Black phosphorus quantum dots work well both in fullerene and non-fullerene polymer solar cells systems.•Black phosphorus quantum dots can work as interface modifier in photovoltaic application.
Black phosphorus quantum dots (BPQDs), as 2D van der Waals crystals, possess remarkable electronic and optoelectronic properties. Their excellent ultra-high mobility and thickness-dependent tunable direct bandgap can meet well the needs of polymer solar cells (PSCs) for adjustable energy levels in different active layer systems. The formation of better energy alignment in the devices is significantly beneficial to the charge transfer, exciton dissociation and reduce charge recombination, which can lead to improved power conversion efficiency (PCE). Herein, it is introduced to modify hole transport layer (HTL) as interfacial modifier (IM) in fullerene and non-fullerene PSCs. The cascade band structure is formed successfully between the anode and polymer donor. In PTB7-Th:PC71BM system, PCE is increased from 8.12% to 9.11%. In PM6:IT-4F system, PCE is enhanced from 11.65% to 12.81%. BPQDs are utilized as HTL IM in conventional device in our study, which can open up a promising route for photovoltaic research.
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