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Defect passivation is a key strategy to prepare high-performance perovskite solar cells (PVSCs). Even though abundant passivation molecules have been applied, the absence of detailed researches with regard to different functional groups in polymer additives may inevitably impede the establishment of passivation molecules selection rules. In this work, three passivation molecules including poly(vinyl alcohol) (PVA), polymethyl acrylate (PMA), and poly(acrylic acid) (PAA) are employed to systematically analyze the passivation effect from hydroxyl, carbonyl, and carboxyl groups. In general, PVA (-OH) can form hydrogen bonds with perovskite and PMA (-C═O) can complex with uncoordinated Pb2+. Specifically, PAA (-COOH) can interact selectively with MA+ and I- ions via hydrogen bonding and complex with uncoordinated Pb2+ to passivate defects more effectively. Hence, the PAA-incorporated PVSCs based on MAPbI3 achieve the champion power conversion efficiency (PCE) of 20.29% with open-circuit voltage up to 1.13 V. In addition, PAA cross-linking perovskite grains can relieve mechanical stress, as well as occupy the major channels to suppress ion migration and water/oxygen erosion. The corresponding unencapsulated devices demonstrate a superior light soaking stability, retaining more than 80% of the original PCE under one sun illumination for 1000 h.

Although tremendous progress has been made in exploring high-energy-density aqueous Zn-ion capacitors (ZICs) recently, their rate capability and power density still remain great challenges. Herein, diblock copolymer micelle derived nitrogen-doped hierarchically porous carbon spheres (N-HPCSs) were fabricated for high energy aqueous ZICs with superior rate performance and power density. It was found that the reasonable pore size distribution and nitrogen-doping of N-HPCSs are favorable for mass transportation by smoothing and reducing the diffusion routes, leading to efficient and fast Zn-ion storage. Consequently, the as-assembled aqueous N-HPCS ZIC yielded a high capacity of 180.4 mA h g−1 at 0.5 A g−1, superior rate performance of maintaining 58.3 mA h g−1 even at an extremely high current density of 100 A g−1, a high energy density of 144.3 W h kg−1, and an excellent power density of 79.9 kW kg−1 with an ultrafast charge time of 2.1 seconds. Moreover, the aqueous N-HPCS ZIC displayed an exciting capacity retention of 98.2% after an ultra-long stability test of 50 000 cycles. This work proposes an efficient strategy to design high-performance electrodes for ZICs with ultrafast Zn-ion storage.

Perovskite polycrystalline films contain numerous intrinsic and interfacial defects ascribed to the solution preparation process, which are harmful to both the photovoltaic performance and the stability of perovskite solar cells (PVSCs). Although various passivators have been proved to be promising materials for passivating perovskite films, there is still a lack of deeper understanding of the effectiveness of the different passivation methods. Here, the mechanism between antisolvent dripping and additive doping strategies on the passivation effects in PVSCs is systematically investigated with a nonfullerene small molecule (F8IC). Such a passivated effect of F8IC is realized via coordination interactions between the carbonyl (C═O) and nitrile (C-N) groups of F8IC with Pb

Perovskite solar cells (PSCs) are a promising photovoltaic technology for stretchable applications because of their flexible, light-weight, and low-cost characteristics. However, the fragility of crystals and poor crystallinity of perovskite on stretchable substrates results in performance loss. In fact, grain boundary defects are the "Achilles' heel" of optoelectronic and mechanical stability. We incorporate a self-healing polyurethane (s-PU) with dynamic oxime-carbamate bonds as a scaffold into the perovskite films, which simultaneously enhances crystallinity and passivates the grain boundary of the perovskite films. The stretchable PSCs with s-PU deliver a stabilized efficiency of 19.15 % with negligible hysteresis, which is comparable to the performance on rigid substrates. The PSCs can maintain over 90 % of their initial efficiency after 3000 hours in air because of their self-encapsulating structure. Importantly, the self-healing function of the s-PU scaffold was verified in situ. The s-PU can release mechanical stress and repair cracks at the grain boundary on multiple levels. The devices recover 88 % of their original efficiency after 1000 cycles at 20 % stretch. We believe that this ingenious growth strategy for crystalline semiconductors will facilitate development of flexible and stretchable electronics.

Perovskite solar cells (PVSCs) have made dramatic progress profiting by various preparation methods in the past few years. Particularly, two-step deposition technique has been demonstrated as an ef...

Tin-based perovskite solar cells (PVSCs) have emerged as the most promising lead-free perovskite materials owing to their superior optoelectronic properties. However, the deficiency of accurate control of the tin-based perovskite crystallization process increases the possibility of unexpected perovskite film morphology and defects, resulting in inferior power conversion efficiency (PCE). Meanwhile, the poor environmental stability of tin-based perovskite films hinders its further development. In this work, a unique polymer [poly(ethylene

Transition metal sulfides (TMS) are a promising pseudocapacitive electrode materials for supercapacitors as their high theoretical capacitance and electrochemical activity. However, its extensive application is limited due to relative unfavorable nanostructure and low surface reactivity. Herein, a hierarchical core-branch electrode material composed of Zn substituted nickel cobalt sulfides nanosheets branched on the NiCo2S4 nanotube arrays combining with conductive carbon cloth (denoted as CC/NiCo2S4@Zn–Ni–Co–S NSAs) is successfully fabricated as excellent cathode for asymmetric supercapacitors. Remarkably, the integration of componental and structural advantages endows the as-prepared CC/NiCo2S4@Zn–Ni–Co–S electrode with better electrochemical performance including ultrahigh specific capacitance (1201 C g−1/2668 F g−1 at 1 A g−1), excellent rate capability (704 C g−1/1564 F g−1 at 50 A g−1) and remarkable cycling stability. More importantly, the assembled CC/NiCo2S4@Zn–Ni–Co–S//activated carbon asymmetric supercapacitor operates in a high voltage window of 1.7 V with a superior energy density of 60.2 W h kg−1 at power density of 849.9 W kg−1 and long-term cycling stability with 91.2% retention after 10 000 cycles. This strategy provides a facile, cost-effective solution to the rational fabricate high performance electrode materials for energy storage devices.

Nickel cobalt sulfide (CoNi2S4)-based materials have attracted extensive attention as electrodes which arise from their high theoretical capacitance, but their wide application is limited by relatively low electrical conductivity and electrochemical stability. Herein, the metal-organic framework (MOF) derived carbon nanowall arrays (CNWAs) are successfully fabricated on carbon cloth (CC) as secondary substrate, which provides more sites for electrodeposition of CoNi2S4. Furthermore, the integration of Ni layer to bridge CoNi2S4 and CNWAs, which is favorable for fast charge transfer, as well as improved conductivity. Thus, the CC/CNWAs@Ni@CoNi2S4 electrode exhibits a remarkable specific capacitance (3163 F g−1/2825 F g−1 at 1 A g−1/5 mV s−1) and rate capability (1503 F g−1/1500 F g−1 at 40 A g−1/50 mV s−1), outperforming others CoNi2S4-based electrodes reported previously. The as-prepared CC/CNWAs@Ni@CoNi2S4//commercial activated carbon asymmetric supercapacitor demonstrates superior electrochemical performance with maximum energy density of 53.8 W h kg−1 at a power density of 801 W kg−1 and long-term cycling stability with 90.1% retention after 10 000 cycles. These remarkable supercapacitive performances are attributed to the rationally hierarchical architecture, high utilization ratio of active materials and aligned ion diffusion channels of the CC/CNWAs@Ni@CoNi2S4 electrode.

Tin-based perovskite solar cells (PVSCs) are regarded as the most promising alternative among lead-free PVSCs. However, the rapid crystallization for tin-based perovskite tends to cause inferior film morphology and abundant defect states, which make poor photovoltaic performance. Here, 1-butyl-3-methylimidazolium bromide (BMIBr) ionic liquids (ILs) with strong polarity and a low melting point are first employed to produce the Ostwald ripening effect and obtain high-quality tin-based perovskite films with a large grain size. Meanwhile, the non-radiative recombination ascribed from defect states can also be effectively reduced for BMIBr-treated perovskite films. Consequently, a photoelectric conversion efficiency (PCE) of 10.09% for inverted tin-based PVSCs is attained by the Ostwald ripening effect. Moreover, the unencapsulated devices with BMIBr retain near 85% of the original PCE in a N2 glovebox beyond 1200 h and about 40% of the original PCE after exposure to air for 48 h.

Although cobalt sulfide is a promising electrode material for supercapacitors, its wide application is limited by relative poor electrochemical performance, low electrical conductivity, and inefficient nanostructure. Here, we demonstrated that the electrochemical activity of cobalt sulfide could be significantly improved by Al doping. We designed and fabricated hierarchical core-branch Al-doped cobalt sulfide nanosheets anchored on Ni nanotube arrays combined with carbon cloth (denoted as CC/H-Ni@Al-Co-S) as an excellent self-standing cathode for asymmetric supercapacitors (ASCs). The combination of structural and compositional advantages endows the CC/H-Ni@Al-Co-S electrode with superior electrochemical performance with high specific capacitance (1830 F g–1/2434 F g–1 at 5 mV s–1/1 A g–1) and excellent rate capability (57.2%/72.3% retention at 1000 mV s–1/100 A g–1). The corresponding all-solid-state ASCs with CC/H-Ni@Al-Co-S and multilayer graphene/CNT film as cathode and anode, respectively, achieve a ...

Among the recent investigations on transparent electrode materials applied in photoelectric devices, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been widely used because of its high transparency and low material cost. However, its relatively low conductivity, hygroscopicity, and acidity limit its further application. Herein, a novel PEDOT:PSS:S-AgNWs composite has been prepared via the in situ oxidative polymerization of EDOT using PSS and 4-mercaptobenzenesulfonic acid-modified silver nanowires (S-AgNWs), in which there are electrostatic interactions between PEDOT and sulfonic groups from PSS and S-AgNWs. When compared with commercial Clevios PH1000, a more crystalline and conductive PEDOT with quinoid conformation was developed by partially substituting PSS with the S-AgNWs; this resulted in the formation of PEDOT:PSS:S-AgNWs showing a lower sheet resistance (64 Ω sq−1 at ∼94.8% transmittance). Furthermore, due to reduced work function, hygroscopicity, and acidic properties of PEDOT:PSS:S-AgNWs derived from the in situ composite between S-AgNWs and PEDOT, as well as the reduction in the PSS content, PEDOT:PSS:S-AgNWs was used as a transparent electrode for the formation of organic solar cells (OSCs), displaying a power conversion efficiency of 10.2% and good storage stability.

In NiOx-based perovskite solar cells (PVSCs), the interfacial redox reaction between Ni3+ (on the surface of NiOx) and A-site cation salt (MAI in perovskite precursor solution) is invariably ignored. This adverse reaction will generate PbI2-rich hole extraction barriers at the NiOx-perovskite interface, which limits hole transmission and increases charge recombination, thus resulting in open-circuit voltage (Voc) loss. Furthermore, it will accelerate perovskite degradation by deprotonating the precursor amine and oxidizing iodide to interstitial iodine, which induces the severe instability of devices. Herein, a physical separation strategy by introducing a modifier layer to obstruct the detrimental reaction is explored. The results demonstrate that the trimethylolpropane tris(2-methyl-1-aziridinepropionate) (SaC-100) depositing onto NiOx can suppress the reaction between Ni3+ and MAI to endow the improvement of conductivity and reduction of interfacial defects, thus reducing Voc loss and enhancing device stability. Moreover, the interfacial energy level alignment and the morphology of perovskite are also optimized. As a result, the PVSCs device based on NiOx/SaC-100 presents the best power conversion efficiency (PCE) of 20.21% with a superior Voc value of 1.12 V. Furthermore, the device shows better light and thermal stability because of the hindering effect and defect passivation effect of SaC-100.

Semi-transparent and self-encapsulated perovskite solar cells could be fabricated by simply laminating the front sub-cell (ITO/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/CH3NH3PbI3) and back sub-cell (FTO/compact-TiO2/mesoporous-TiO2/CH3NH3PbI3), without vacuum-evaporating metal electrode. The addition of chlorobenzene (CB) between two perovskite layers accelerated perovskite crystals interfusion and close interfacial contact from two separated sub-cells, which contributed to perovskite film with high crystallinity and light absorption in laminated cells. The self-encapsulated perovskite solar cell (device area of 0.39 cm2) with CB treatment not only showed power conversion efficiency of 6.9%, but also existed excellent stability even if soaking in water for 24 h. This novel approach to fabricate semi-transparent, solution-processible, cost-effective and high-stable perovskite solar cells may provide a reliable royal road for realizing commercial application in exterior building window, with the combination of large-area roll-to-roll printing technique, etc.

In this work, we have rationally designed and successfully synthesized a reduced graphene oxide (GO) functionalized with fluorine atoms (F-rGO) as a hole-transport layer (HTL) for polymer solar cells (PSCs). The resultant F-rGO has an excellent dispersibility in dimethylformamide without any surfactants, leading to a good film-forming property of F-rGO for structuring a stable interface. The recovery of conjugated C=C bonds in GO oxide after reduction increases the conductivity of F-rGO, which enhances the short-circuit current density of photovoltaic devices from 15.65 to 16.89 mA/cm2. A higher work function (WF) (5.1 eV) of F-rGO than that of GO (4.9 eV) is attributed to the fluorine group with a high electronegativity. Naturally, the better-matched WF with the highest occupied molecular orbital level of the PTB7-Th (5.22 eV) donor induces an improved energy alignment in devices, resulting in a superior open-circuit voltage of the device (0.776 vs 0.786 V). Consequently, the device with F-rGO as the HTL achieves a higher power conversion efficiency (8.6%) with long-term stability than that of the devices with GO HTLs and even higher than that of the poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) control device. These results clearly verify that the F-rGO is a promising hole-transport material and an ideal replacement for conventional PEDOT/PSS, further promoting the realization of low-cost, solution-processed, high-performance, and high-stability PSCs.

A solution-processable, aggregation-induced emission-type three-dimensional molecule TPE-DPP4 was synthesized in a facile way. TPE-DPP4 can function as a light-capturer, grain-boundary filler as well as an electron-donor for perovskite + TPE-DPP4 bulk heterojunction hybrid film. The perovskite solar cells obtained with TPE-DPP4 resulted in enhanced power conversion efficiency of 14.1% with 40% enhancement to the device compared with pristine perovskite.

With the cooperative effects of pre-treatment with a polyethylene glycol 4000 (PEG4000) additive and post-treatment with sulfuric acid (H2SO4), the conductivity of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) was improved remarkably. By this method, the pre-treatment PEG4000 additive would form hydrogen bonds with the PSS in PEDOT:PSS, which can effectively reduce the interactions between PEDOT and PSS. Subsequently, the post-treatment H2SO4 could efficiently wash away the intrinsic PSS together with the insulating PEG4000 additive, which not only improved the crystallization but also further optimized the conformation of the PEDOT chains. Meanwhile, the work function of the resulting PEDOT:PSS (S-PEDOT:PSS:PEG4000 (6.5 wt%)) was remarkably reduced and it became more suitable for use as a cathode, compared with pristine PEDOT:PSS. By means of these simple process technologies, a highly conductive and transparent PEDOT:PSS film was achieved. A polymer solar cell device using S-PEDOT:PSS:PEG4000 (6.5 wt%) as the cathode realized a notable power conversion efficiency of 8.1%, which was even superior to an indium tin oxide cathode based device.

Pure chlorobenzene (CBZ) and 2-propanol (IPA) or mixed-solvent assisted spin-coating have been applied to one-step fabricate CH3NH3PbI3 and CH3NH3PbI3−xClx perovskite films, respectively. However, with the treatment of pure- or mixed solvent, there are obvious differences in the formation of CH3NH3PbI3 and CH3NH3PbI3−xClx perovskite films with full coverage and large crystal grain size, as well as the role in the photovoltaic performance. Furthermore, the nucleation and growth dynamics of perovskite crystals have been taken into consideration with the activation energy of transporting crystallizing segments across the crystal interface and the formation free energy of a critical-sized nucleus. Planar heterojunction (PHJ) perovskite solar cells (PSCs) based on CH3NH3PbI3 by mixed-solvent treatment exhibit a poor power conversion efficiency (PCE) owing to the formation little amount of perovskite crystals with low crystallinity. While pure CBZ treatment renders the corresponding device get efficiency of 8.1%, which is due to the formation of uniform CH3NH3PbI3 thin film with higher surface coverage and crystallinity. Inversely, PSCs based on CH3NH3PbI3−xClx with mixed-solvent shows the highest PCE of 9.2%, short-circuit current density (Jsc) of 16.06 mA/cm2 and fill factor (FF) of 63.6% with high device reproducibility and low photocurrent hysteresis, because of possessing higher light absorption ascribed from bigger crystal size and better surface morphology with no pin-holes. These results will provide significant guidance for CH3NH3PbI3 and CH3NH3PbI3−xClx perovskite device performance optimization and large-scale application by pure- and mixed-solvent treatment.

The high-quality CH3NH3PbI3 film morphology and delicate interfacial modification are critical to achieve high-performance perovskite solar cells (PSCs). Here, we report a facile and efficient method to optimize the morphology and interface of a perovskite solar cell by molybdenum isopropoxide (Mo-IPA) solution treatment during the fabrication process of the perovskite film. After simply being treated with Mo-IPA, both highly crystalline perovskite film and MoOX interfacial layer could be simultaneously achieved. The Mo-IPA treatment can induce a denser and more uniform morphology of CH3NH3PbI3 with larger crystals size than pure isopropyl alcohol (IPA) treatment. At the same time, the formation of MoOX can effectively elevate the valence band maximum (VBM) of the perovskite, as a result to favor a better energy alignment with 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)9,9′-spirobifluorene (Spiro-MeOTAD) hole transport layer (HTL) for efficient hole extraction. With those excellent properties obtained...

The 4-halobenzoics (XBA) including 4-fluorobenzoic acid (FBA), 4-chlorobenzoic acid (CBA), 4-bromobenzoic acid (BBA) and 4-iodobenzoic acid (IBA) have been applied to modify poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) by simply spin-coating solvent treatment. A universal and significant improvement in the conductivity of PEDOT:PSS (from ∼1 S/cm to more than 3300 S/cm) has been achieved by XBA modification, which results from the acid XBA-induced phase segregation, depletion of PSS chains and the conformational change of the conductive PEDOT chains. Especially, the oxidation CBA treated PEDOT:PSS exhibits low sheet resistance of 43 Ω/sq and transparency of over 80% in the visible range, which are comparable to those of indium tin oxide (ITO). The modified PEDOT:PSS has been facilely applied as the transparent anode for high-efficiency ITO-free organic solar cell device without hole transport layer. The high power conversion efficiency of 7.9% has been achieved by employing CBA treated PEDOT:PSS as anode for ITO-free device based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2- b ;4,5- b ′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4- b ]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th):[6,6]-phenyl-C71 butyric acid methyl ester (PC 71 BM), which is comparable to the corresponding devices based on the traditional ITO anode.

In-situ synthesis and rapid assembly of CdS quantum dots (QDs) in main-chain liquid-crystalline polymer poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBDTTT-C12) and side-chain liquid-crystalline polymer poly[4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-alt-3,6-bis(thiophen-5-yl)2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione] (PBDTDPPcbp) was formed. This was driven by the organization of liquid-crystals (LC) at 150 °C, due to mesotropic state of mesogens. Further under the applied electric field ( V app ), the orientation of QDs could be regulated along with the highly crystalline nanofibers to form the separated organic and inorganic orderly channels, which was benefit for the electron transportation and collection. The inverted polymer solar cells (i-PSCs) devices with ZnO modified by PBDTTT-C12@CdS and PBDTDPPcbp@CdS interfacial layers (ILs) after rinsing polymers with chloroform as electron transport layers (ETLs) and poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C 61 -butyric acid methyl ester (P3HT:PC 61 BM) as active layer showed superior photovoltaic performance with average power conversion efficiency (PCE) of 3.5% and 3.9%, respectively. With application of suitable V app , the more orderly CdS QDs interfacial nanostructures were in favor of the higher electron mobility and better interfacial contact between cathode and active layer, consequently enhanced the devices performance.

Sulfonated carbon nanotubes (SCNTs) act as secondary polymerization templates for in situ preparation of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). It essentially reduces the content of insulating PSS, instead of pre- or post-solvent processing, for a highly conductive PEDOT:PSS:SCNT composite electrode. The PEDOT:PSS:SCNT was characterized with regard to its composition, conformation, stability, morphology, optoelectronic devices, and work function behavior. The PEDOT:PSS:SCNT films with a low work function (4.4 eV) and remarkable optoelectronic properties (over 3500 S cm−1, ∼83% transmittance at a 70 nm thickness film) were suitably integrated as a cathode in organic solar cells (OSCs) with a power conversion efficiency (PCE) of 9.91% and perovskite solar cells (PSCs) with a PCE of 13.31%.

The inclusions of solution-processed ZnO electron transport layers (ETLs) of inverted polymer solar cells can lead to various surface defects, which can act as interfacial recombination centers for photogenerated charges and thereby can lead to degradation of the device performance. Three-dimensional (3D) CdS with different morphologies, such as flower-like CdS (F-CdS), branched CdS (B-CdS), and spherical CdS (S-CdS), are synthesized to modify ZnO ETLs, by effectively removing the intragap states of the ZnO nanocrystal films by forming ZnO/F-CdS, ZnO/B-CdS, and ZnO/S-CdS composite ETLs, respectively. Moreover, ZnO/CdS possesses higher electron mobility and provides a larger interface between the ETL and active layer, which is beneficial for enhancing the power conversion efficiency (PCE) of the inverted organic solar cells. In particular, a device based on a ZnO/S-CdS ETL and thieno[3,4-b]-thiophene/benzodithiophene (PTB7):[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) active layer achieved a PCE of 8.0%, together with better long-term stability.

High quality one-dimensional ZnO nanoarrays (ZnO NAs) prepared by simple hydrothermal process, in which the length, density and surface defects are adjusted by controlling the hydrolysis time (Th) and the concentration of hydrolysate, have been successfully applied as the electron transport layer (ETL) in the inverted polymer solar cells. ZnO NAs with suitable length and density provide direct and efficient path for electron transmission, which is good for improving the photovoltaic performance. In order to reduce the surface defects of ZnO NAs and modify the interfacial contact between ZnO NAs layer and active layer, CdS quantum dots (QDs) have been employed to sensitize ZnO NAs’ surface via successive ionic layer adsorption and reaction (SILAR) and further fabricate ZnO@CdS core/shell NAs as ETL. Compared to the bare ZnO NAs, the ZnO/CdS core/shell ETL can reduce the recombination of carriers, increase the electron mobility and enhance electron extraction. By adjusting the length and density of ZnO NAs, as well as modifying with CdS, the power conversion efficiency (PCE) of the inverted polymer solar cells based on ZnO/CdS core/shell ETL and poly(3-hexylthiophene):(6,6)-phenyl-C61 butyric acidmethyl ester (P3HT:PC61BM) has been improved to 3.8 % with better long-term stability.

Highly uniform one-dimensional ZnO nanoarrays (ZnO NAs) fabricated by hydrothermal process were successfully explored as electron transport layer (ETL) for offering a direct and efficient path for electron transport in inverted polymer solar cells (PSCs). The inorganic CdS shell layer by in situ growth on the ZnO NAs surface was used to passivate and repair the surface defects of ZnO NAs. To further engineer the ZnO surface and improve the compatibility between ETL of inorganic ZnO/CdS core/shell and polymer blend contact junction, those organic molecules of 3,6,7,10,11-pentakis-(hexyloxy)-2-hydroxytriphenylene (TP-OH), 1-pyrenol (Py-OH) and 4'-(7-hydroxy-heptanoyl)-biphenyl-4-carbonitrile (BP-OH) were respectively spin-coated on the ZnO NAs/CdS surface to fabricate ETL based on ZnO/CdS/TP-OH NAs, ZnO/CdS/Py-OH NAs, ZnO/CdS/BP-OH NAs. The pi-pi interactions between the organic molecules and fullerene acceptors could lead to the well-organized distribution of active layer materials, which is in favor of the enhancement of electron selectivity and the reduction of recombination probability of electrons and holes. The incorporation of ZnO/CdS/Py-OH NAs as ETL into the inverted PSCs based on P3HT:PC61BM resulted in a superior power conversion efficiency (PCE) of 4.2% with enhanced short circuit current (J(sc)) and fill factor (FF), compared to 3.1% for bare ZnO NAs, due to the intermolecular close-stacking and relative stronger pi-pi interaction energy between Py-OH and fullerenes. In addition, the sensitized ZnO surface led to intimate interface between ETL and active layer, which would be in favor of increasing the stability of the device. (C) 2015 Elsevier B.V. All rights reserved.

Sequential deposition is certified as an effective technology to obtain high-performance perovskite solar cells (PVSCs), which can be derivatized into large-scale industrial production. However, dense lead iodide (PbI2 ) causes incomplete reaction and unsatisfactory solution utilization of perovskite in planar PVSCs without mesoporous titanium dioxide as a support. Here, a novel autonomously longitudinal scaffold constructed by the interspersion of in situ self-polymerized methyl methacrylate (sMMA) in PbI2 is introduced to fabricate efficient PVSCs with excellent flexural endurance and environmental adaptability. By this strategy perovskite solution can be confined within an organic scaffold with vertical crystal growth promoted, effectively inhibiting exciton accumulation and recombination at grain boundaries. Additionally, sMMA cross-linked perovskite network can release mechanical stress and occupy the main channels for ion migration and water/oxygen permeation to significantly improve operational stability, which opens up a new strategy for the commercial development of large-area PVSCs in flexible electronics.

Polymer solar cells (PSCs) with high short current density (Jsc) have been fabricated through a facile way by using a low-cost polyelectrolyte-modified poly(3,4- ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS, P VP Al 4083) bilayer film as anode buffer layer. Spin-coating a layer of sulfonate poly(aryl ether sulfone) (SPES) on the surface of PEDOT:PSS hole-transporting layer (HTL) is found to dramatically improve the Jsc value even up to 21.66 mA cm–2. The notable Jsc is demonstrated to be correlated with interaction between the SPES and PEDOT, which removes the insulator of PSS with formation of continuous PEDOT domains, consequently leading to the improved conductivity and more imitate interfacial contact. It should be noted that the notable Jsc also partly results from the effect of a second anode due to the high conductivity of SPES-modified PEDOT:PSS. Through systematically investigation on a series of devices with different areas, it can be found that a real effective area of the devices ...

Ordered microstructure and high conductivity of poly(3,4-ethylenedioxythiophene):poly-(styrene sulfonate) (PEDOT:PSS, commercial product PH1000) films for a transparent anode were obtained by liquid-crystalline ionic liquids modification. By spin-coating 1-hexadecyl-3-methylimidazolium hexafluorophosphate ([C16MIm]PF6) or 1-hexadecyl-3-methylimidazolium tetrafluoroborate ([C16MIm]BF4) on the PH1000 film, half of the insulating PSS on the top surface of PH1000 could be successfully removed and the PEDOT formed an ordered and continuous molecular packing. The conductivity of PH1000 dramatically increased from 0.4 S cm−1 to 1457.7 S cm−1 for PH1000/[C16MIm]PF6 and 1243.8 S cm−1 for PH1000/[C16MIm]BF4. At the same time, spontaneous orientation of the liquid-crystalline ionic liquids with liquid-crystallinity further promoted the ordered packing arrangement of both PH1000 and the active layer. The power conversion efficiency based on PH1000/[C16MIm]PF6 and PH1000/[C16MIm]BF4 as the anode is comparable to that obtained from the device with indium tin oxide (ITO) as the anode. In addition, liquid-crystalline ionic liquids modification is also good for the energy alignment, facilitating charge injection and transport, without any extra hole transport layer. Furthermore, these novel liquid-crystalline ionic liquids modification PH1000 anodes have potential applications in the fabrication of ITO-free large-area flexible printed polymer solar cells.

Novel composites based on cubic binary nickel cobaltite oxide intimately standing on nitrogen doped reduced graphene sheets (NRGO–NiCoO2) were prepared by a simple one step hydrothermal synthesis. The results showed that the highly crystalline NiCoO2 nanoparticles with a uniform size were homogeneously distributed on nitrogen-doped reduced graphene sheets (NRGO). The homogeneous composites combined NiCoO2, which has high specific capacitance, and NRGO, which has efficient electronic conductivity, to consequently yield low resistance conduction between metal oxides and graphene due to a barrier-free contact. The synergistic effect of NRGO substrates and NiCoO2 nanoparticles promoted the electrochemical performance of the composites. The electrochemical properties of NRGO–NiCoO2 can be easily tuned by altering the amount of nitrogen-composed reducer. The NRGO–NiCoO2 composites exhibited a remarkable specific capacitance of 508 F g−1 at 0.5 A g−1, an excellent rate performance in cyclic voltammetry test (from 5 to 90 mV s−1) and good galvanostatic charge–discharge measurements (from 0.5 to 20 A g−1). The capacitance was maintained at 93% of the original value even after 2000 cycles. The flexible devices were assembled, which possessed a specific capacitance of 58 F g−1 at 0.5 A g−1. This facile one-step strategy is an effective method for developing excellent supercapacitor electrodes.

Novel zinc oxide nanoparticles (ZnO NPs) modified by silanization using triethoxy-1H,1H,2H,2H-tridecafluoro-n-octylsilane (TTFO), referred to as ZnOF NPs, have been successfully synthesized. Driven by the surface segregation behavior of the fluoroalkyl chains ascribed to their low surface energy, ZnOF NPs can migrate from the blend system with poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) to the surface of the active layer during the annealing process and consequently self-assemble as a cathode buffer layer. The addition of functionalized ZnOF NPs assists in the stacking of the P3HT chains to form a favorable morphology of the active layer with remarkable phase separation, especially upon annealing optimization in o-DCB solvent. The best power conversion efficiency (PCE) of 2.4% is achieved with an open-circuit voltage (Voc) of 0.49 V, short-circuit current density (Jsc) of 8.1 mA cm−2 and fill factor (FF) of 61%, based on the self-assembled cathode buffer layer of ZnOF NPs (5 wt%) upon annealing in o-DCB. Therefore, this novel approach could realize the fabrication of both the active layer and cathode buffer layer through a single step, which not only simplifies the fabrication procedure and reduces the manufacturing cost of polymer solar cells, but also increases the PCE, by reduction of the Schottky barrier at the interface, and the stability of the devices.

Sulfonated carbon nanotubes (S-CNTs) and sulfonated graphene (S-Gra) with superior dispersibility were successfully prepared to modify poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) for applications in polymer solar cells (PSCs). The synergetic effect between S-CNTs/S-Gra and PEDOT:PSS could remove excess insulating PSS chains leading to an obvious phase separation between the PEDOT and PSS chains, which allows the formation of more conductive PEDOT channels. The PEDOT:PSS (Clevios PH 4083):S-CNTs with well-matched work function, favorable morphology, optimized hydrophobicity and superior hole mobility is demonstrated to be an excellent hole transport layer (HTL) for PSCs. However, the PEDOT:PSS (Clevios PH 4083) modified by sulfonated graphene with stacked and wrinkled lamellae as an HTL renders a rough morphology and has a negative impact on the morphology of the active layer, consequently resulting in a poor device performance. Excitingly, PEDOT:PSS (Clevios PH 1000) modified with S-Gra shows high conductivity, because the sulfonated graphene lamellae contribute to the connection between the insulator and conductive PEDOT islands and improves the charge conduction. The PH1000:S-Gra with multiple layers presents excellent electrical conductive properties and a high transmittance (sheet resistance of ∼45 Ω sq(-1) and transmittance of ∼85.5% at 550 nm), which possess great potential for its application as a transparent conductive and flexible electrode in organic electronics.

A smart ZnO@PNIPAM hybrid was prepared by grafting thermal responsive poly(N-isopropylacrylamide) (PNIPAM) on zinc oxide (ZnO) nanoparticles via surface-initiated atom transfer radical polymerization (ATRP). The thermal gravimetric analysis (TGA) shows that the grafting amount of PNIPAM was about 38%, and the SEM images show that the PNIPAM chains can prevent the aggregation of ZnO nanoparticles. The responsive properties of ZnO@PNIPAM were measured by photoluminescence spectra, and the results demonstrate that the PNIPAM chains grafted on ZnO surfaces can realize reversible thermal responsive and photoluminescence properties. An anticancer drug, doxorubicin (Dox), was used as a model drug and loaded into the hybrid nanoparticles, and an in vitro drug release test implied that ZnO@PNIPAM could work as a thermal responsive drug delivery system. Furthermore, pH sensitive drug releases were carried out in acetate buffer at pH 5.0 and pH 6.0 and in water at pH7.0, and the results showed evident pH dependency, showing its pH responsive properties.

Two-dimensional graphene-CdS (G-CdS) semiconductor hybrid nanosheets were synthesized in situ by graphene oxide (GO) quantum wells and a metal-xanthate precursor through a one-step growth process. Incorporation of G-CdS nanosheets into a photoactive film consisting of poly[4,8-bis-(2-ethyl-hexyl-thiophene-5-yl)-benzo[1,2-b:4,5-b]dithiophene-2,6-diyl]-alt-[2-(2-ethyl-hexanoyl)-thieno[3,4-b]thiophen-4,6-diyl] (PBDTTT-C-T) and [6,6]-phenyl C70 butyric acid methyl ester (PC70 BM) effectively decreases the exciton lifetime to accelerate exciton dissociation. More importantly, the decreasing energy levels of PBDTTT-C-T, PC70 BM, and G-CdS produces versatile heterojunction interfaces of PBDTTT-C-T:PC70 BM, PBDTTT-C-T:G-CdS, and PBDTTT-C-T:PC70 BM:G-CdS; this offers multi-charge-transfer channels for more efficient charge separation and transfer. The charge transfer in the blend film also depends on the G-CdS nanosheet loadings. In addition, G-CdS nanosheets improve light utilization and charge mobility in the photoactive layer. As a result, by incorporation of G-CdS nanosheets into the active layer, the power-conversion efficiency of inverted solar cells based on PBDTTT-C-T and PC71 BM is improved from 6.0 % for a reference device without G-CdS nanosheets to 7.5 % for the device with 1.5wt % G-CdS nanosheets, due to the dramatically enhanced short-circuit current. Combined with the advantageous mechanical properties of the PBDTTT-C-T:PC70 BM:G-CdS active layer, the novel CdS-cluster-decorated graphene hybrid nanomaterials provide a promising approach to improve the device performance.

In situ growth of cadmium sulfide (CdS) quantum dots (QDs) was achieved directly through solvent-assisted grafting in the self-assembled templates of amphiphilic all conjugated diblock copolythiophene, poly(3-hexylthiophene)-b-poly(3-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)methylthiophene) (P3HT-b-P3TEGT) and gas–solid reaction. Such diblock polymer templates allowed a desired amount of cadmium sulfide salt (Cd(Ac)2) to easily accomplish dispersion and self-assembly via controlled assembling block copolymers in selective solvents. After P3HT-b-P3TEGT polymer templates grafted with Cd2+ precursor (P3HT-b-P3TEGT/Cd2+) reacting in hydrogen sulfide (H2S) gas, one-dimensional core–shell nanobeams network P3HT-b-P3TEG/CdS (donor–acceptor) was formed with excellent phase separation between P3HT-b-P3TEGT crystalline domains and inorganic CdS QDs domains at nanoscales, which was driven by the interaction between oxygen atoms of ethylene oxide side chains and Cd2+ ions, and the thermodynamic equilibrium between polyme...

In this article, we present a novel and promising approach to enhance the device performance and stability by the simple incorporation of all conjugated polythiophene diblock copolymers, poly(3-hexylthiophene)-b-poly(3-triethylene glycol thiophene) (P3HT-b-P3TEGT), into the active layer based on inverted device structures. During the spin-coating process, the triethylene glycol side chains of P3HT-b-P3TEGT would spontaneously migrate vertically towards the active layer surface and form a nanoscale self-assembled anode buffer layer, which simultaneously drives the orderly packing of donor polymer chains and vertical phase separation morphology, allowing electrons and holes to move more efficiently to the respective electrode. Moreover, the nanoscale self-assembled buffer layer can form interfacial modification and ohmic contact between the active layer and Ag (or MoO3/Ag) electrode, reduce the contact resistance of the device, and increase the electrical conduction of the device, especially upon chelating lithium ions (Li+) to the triethylene glycol side chains of P3HT-b-P3TEGT. Combining the above advantages, the efficiency and stability of the polymer solar cells are enhanced. A remarkable improvement in the PCE with 7.3% (measured in air) is obtained for PBDTTT-C-T:PC71BM devices.

Significant efforts have been dedicated to the interface engineering of organic photovoltaic device, suggesting that the performance and aging of the device are not only dependent on the active layer, but also governed by the interface with electrodes. In this work, controllable interfacial dipole and conductivity have been achieved in ionic liquids (ILs) modified poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). We conclude that an appropriate interfacial conductivity is as essential as the suitable work function for an efficient buffer layer. Through forming favorable dipoles for hole transportation and reducing the film resistance by [HOEMIm][HSO4] treatment, an averaged performance of 8.64% is obtained for OPVs based on PTB7:PC71BM bulk heterojunction with improved stability. However, the improvement of performance is inconspicuous for OPVs based on PTB7-Th:PC71BM bulk heterojunction due to the incompetent energy level of high concentration ILs-modified PEDOT:PSS. The enhanced in-plane conductivity will reduce shunt resistance, and produce a fake high short-circuit current density (J

Biodegradable poly(butylene succinate-co-ethylene glycol) (PBSG)/multiwalled carbon nanotube (MWCNT) nanocomposites were successfully prepared through physical blending and silication between PBSG and acyl aminopropyltriethoxysilane functionalized multiwalled carbon nanotube (MWCNT-APTES). Nuclear magnetic resonance (NMR) spectra observations revealed that the PBSG chains were covalently attached to the MWCNT-APTES by hydrolysis. PBSG/MWCNT-APTES nanocomposites after hydrolysis showed excellent interfacial compatibility between PBSG and MWCNT-APTES, which was helpful for the dispersion of MWCNT in the PBSG matrix. The incorporation of MWCNT-APTES accelerated the crystallization of PBSG in the nanocomposites for both approaches of physical blending and hydrolysis due to the heterogeneous nucleation effect of MWCNT while the crystal structure of PBSG was remained. Furthermore, the crystallization rate of PBSG in PBSG/MWCNT-APTES nanocomposites after hydrolysis was slower than that in the nanocomposite by physical blend. The tensile strength and modulus of the nanocomposites increased about 6% and 11% with the addition of only 1 wt% MWCNT-APTES compared with that of neat PBSG, and was larger for the PBSG/MWCNT-APTES nanocomposites after hydrolysis. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

The biodegradable poly(butylene succinate) (PBS)/poly(ethylene oxide)-polyhedral oligomeric silsesquioxane (PEO-POSS) nanocomposites were prepared by the solution blending and melt-injection methods. The effect of PEO-POSS on the non-isothermal and isothermal crystallization, morphology, as well as mechanical properties of PBS was carefully investigated. The PEO-POSS nanoparticles dispersed well in the PBS matrix, with the diameters around 30 nm. From isothermal crystallization analysis, the incorporation of PEO-POSS enhanced the crystallization of PBS due to the heterogeneous nucleation effect while the crystal structure of PBS remained. PBS/PEO-POSS nanocomposites showed of higher glass transition temperatures than that of neat PBS, attributing to the existence of PEO-POSS decreasing the flexibility of PBS chains. The elongation at break of the PBS/PEO-POSS nanocomposites reached the maximum value with PEO-POSS content of 5 wt%. However, the elastic modulus of PBS decreased after the incorporation of PEO-POSS. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

Biodegradable poly(butylene succinate) (PBS)/single-walled carbon nanotube (SWCNT) nanocomposites were successfully prepared through silication and physical blend between PBS and acyl aminopropyltriethoxysilane functionalized single-walled carbon nanotube (SWCNT-APTES), which was obtained from acylate between 3-aminopropyltriethoxysilane and acyl chloride functionalized single-walled carbon nanotube. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) observations revealed that the PBS chains were covalently attached to the SWCNT-APTES by hydrolysis. PBS/SWCNT-APTES nanocomposites after hydrolysis exhibited strong interfacial interaction between SWCNT-APTES and PBS matrix, leading to a less agglomeration. However, the PBS/SWCNT-APTES nanocomposite prepared by only physical blend without hydrolysis exhibited severe reagglomeration of SWCNT in the PBS. The addition of SWCNT-APTES enhanced the crystallization of the PBS in the nanocomposites for both approaches of hydrolysis and physical blend due to the heterogeneous nucleation effect while the crystal structure of PBS remained. Especially, a more significant increase of crystallization rate for physical blend was present as comparison to PBS/SWCNT-APTES after hydrolysis due to the higher diffusion constant, which is attributed to the change of surface properties of nanotubes. Furthermore, the incorporation of SWCNT-APTES improved the storage modulus of the nanocomposites compared with that of neat PBS. The PBS/SWCNT-APTES nanocomposites after hydrolysis showed of higher tensile strength than PBS/SWCNT-APTES nanocomposite without hydrolysis.

A series of aliphatic biodegradable poly(butylene succinate-co- dl -lactide) (PBSLA) copolyesters were synthesized with the aim of improving the degradation rate of poly(butylene succinate) (PBS) by incorporation of dl -oligo(lactic acid) (OLA) into the PBS molecular chains. The composition and sequential structure of the aliphatic copolyesters were investigated by proton nuclear magnetic resonance ( 1 H NMR) spectroscopy. The crystallization behaviors, the crystal structure and morphology of the copolyesters were investigated by using differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarizing optical microscopy (POM), respectively. The results indicate that the crystallization of the copolyesters was restricted by the incorporation of lactide (LA) units, which further tuned the mechanical properties of the copolyesters. The copolyesters could form complete spherulites and exhibit the same crystal structure as that of PBS. Enzymatic study indicated that the copolyesters with higher content of LA units degraded faster, and the degradation began in the amorphous regions and then in the crystalline regions. The morphology and the resulting degradation products of the copolyesters were investigated by scanning electron microscopy (SEM) and 1 H NMR analysis during the degradation process.

The poly(ethylene terephthalate-co-ethyleneoxide-co-DL-lactide) copolymers were successfully prepared by the melt reaction between poly(ethylene terephthalate), poly(ethylene glycol), and DL-oligo(lactic acid) without any catalysts. The transesterification between ethylene terephthalate, ethyleneoxide, and lactide segments during the reaction was confirmed by the 1H NMR analysis. The effect of reaction temperatures and the starting feed ratios on the molecular microstructures, molecular weights, solubility, thermal properties, and degradability of the copolyesters was extensively studied. The values of crystallization temperature, melting temperature, crystallization, and melting enthalpy of the copolyesters were found to be influenced by the reaction temperatures, starting feed ratios, etc. The copolyesters showed good tensile properties and were found to degrade in the soil burial experiments during the period of 3 months. The morphology of the copolyester films were also investigated by scanning electron microscopy during soil burial degradation. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

The copolymers of poly(1,4-butylene terephthalate-co-ethylene oxide-co-DL-lactide), obtained by the transesterification reactions of poly(butylenes terephthalate) with poly(ethylene glycol DL-oligo(lactic acid), were fabricated into porous scaffolds by the established solvent-casting and particulate-leaching technique with NaCl as the porogen. The morphology of the porous scaffolds were investigated by the scanning electron microscopy (SEM), and the pores within the scaffold were proven to be interconnective ranging in size from 200 to 400 μm. The human bone marrow mesenchymal stem cells (MSC) seeded on the scaffolds were confirmed to survive and proliferate within the pores of the scaffold with the observation by immunofluorescence microscope and SEM. In vivo implantation of MSC-seeded scaffolds into athymic nude mice showed significant tissue formation in the subcutaneous sites of the immunodeficient mice at 3, 4, 6, and 9 weeks. The results indicate that the scaffolds were biocompatible with MSC and the host tissue in vitro and in vivo.

A reactive blend of poly(ethylene glycol) (PEG) and DL-oligo(lactic acid) (OLA) is obtained at high temperature to produce partial PEG/OLA multiblock copolymer without purification. The reactive blend of PEG and OLA easily reacts with poly(1,4-butylene terephthalate) (PBT) in the melt leading to the formation of high-molar mass poly(1,4-butylene terephthalate-co-ethylene oxide-co-DL-lactide) (PBTEOLA) copolymers. The analysis from 1H NMR and solubility test reveals that the transesterification between butylene terephthalate (BT), ethyleneoxide (EO), and lactide (LA) segments during synthesis is unavoidable. The copolyesters are segmented copolyesters with certain random properties, as confirmed by their thermal behavior. The copolyesters show only one melting temperature (Tm) on the second heating run and one crystallization temperature (Tc) on the cooling cycle from differential scanning calorimetry measurement. With increase of OLA feeding composition in PEG/OLA blend or increase of content of PEG/OLA blend, the Tm and Tc of copolyesters decrease, and solubility increases. The conventional size-exclusion chromatography polystyrene calibration estimates weight-averaged molecular weight of the copolyester to be as high as 66,600 g/mol. Mechanical tests indicate that the copolyesters exhibit high Young's modulus of 50–100 MPa and good elongation at break of 32–137%. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

New alcohol-soluble conjugated small molecule electrolytes (CSMEs), 3,6-bis-(5-benzoic acid-thiophen-2-yl)-2,5-bis-(2-ethylhexyl)-2,5-dihydro-pyrrolo[3,4-c]pyrrole-1,4-dione liquid crystalline (DPP-COOH) and di-tetrabutylammonium cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II) dye (N719), are developed as interfacial modification in inverted polymer solar cells (PSCs). Further optimization of the device architecture by combining the electrolytes as hole and electron buffer layers can significantly promote the photovoltaic performances of PSCs due to the integrated advantages of excellent alcohol processability, hole and electron mobility, interfacial dipole effect and good energy level alignment with electrodes. Moreover, the PSCs with the CSMEs interlayers based on narrow band-gap PTB7:PC71BM active layers show considerable improvement in power conversion efficiency (PCE), compared with P3HT:PCBM active layer-based devices. Devices with DPP-COOH and N719 modifications after thermal treatment at 120 °C exhibit the PCE of 8.0% and 7.6% under AM 1.5G irradiation, respectively, improving from 6.7% PCE of the pristine device without any interfacial layer. Encouragingly, the simultaneous use of CSMEs as hole and electron modification layers can boost the PCE to 8.2%. These findings demonstrate that the utilization of alcohol-soluble small molecule conjugated electrolytes with lower band gaps as interfacial modification layers is an effective and practical strategy for improving photovoltaic performance in PSCs.