An Efficient and Stable Perovskite Solar Cell with Suppressed Defects by Employing Dithizone as a Lead Indicator.

The defects in perovskite films are one of the most non-negligible factors that can attenuate the performances of perovskite solar cell. This work fabricates defect-reduced perovskite film by using the lead indicator (dithizone) as an additive of perovskite functional layer. The dithizone can retard the crystallization rate of perovskite films, passivate the defects, and enhance the structure stability of perovskite by coordinating with lead atoms. As a result, the device doped with dithizone yields outstanding power conversion efficiency and stability.

An Interconnected Ternary MIn2 S4 (M=Fe, Co, Ni) Thiospinel Nanosheet Array: A Type of Efficient Platinum-Free Counter Electrode for Dye-Sensitized Solar Cells.

The ternary iron-group thiospinels of metal diindium sulfides (MIn2 S4 , M=Fe, Co, Ni) with a vertically aligned nanosheet array structure are fabricated through an in situ solvothermal method on F-doped tin oxide (FTO) substrates, which are employed as one type of platinum (Pt)-free counter electrodes (CEs) in structure-dependent dye-sensitized solar cells (DSSCs). A DSSC assembled with ternary CoIn2 S4 CE achieves an photoelectric conversion efficiency (PCE) of 8.83 %, outperforming than that of FeIn2 S4 (7.18 %) and NiIn2 S4 (8.27 %) CEs under full sunlight illumination (100 mW cm-2 , AM 1.5 G), which is also comparable with that of the Pt CE (8.19 %). Putting aside that the interconnected nanosheet array provides fast electron transfer and electrolyte diffusion channels, the highest PCE of CoIn2 S4 based DSSC results from its largest specific surface area (144.07 m2 g-1 ), providing abundant active sites and the largest electron injection efficiency from CE to electrolyte.

Synergistic effects of caesium closo-dodecaborate on buried interface for efficient and stable perovskite solar cells.

The defects and strain of the buried SnO2/perovskite interface seriously affects the performances of n-i-p type perovskite solar cells. Herein, caesium closo-dodecaborate (B12H12Cs2) is introduced into buried interface to improve the device performances. B12H12Cs2 can passivate the bilateral defects of the buried interface, including the oxygen vacancy and uncoordinated Sn2+ defects on SnO2 side and the uncoordinated Pb2+ defects on perovskite side. Three-dimensional aromatic B12H12Cs2 can promote the interface charge transfer and extraction. [B12H12]2- can enhance the interface connection of buried interface by forming B-H---H-N dihydrogen bond and coordination bonds with metal ions. Meanwhile, the crystal properties of perovskite films can be improved and the buried tensile strain can be released by B12H12Cs2 due to the matched lattice between B12H12Cs2 and perovskite. In addition, Cs+ can diffuse into perovskite to reduce the hysteresis behavior by inhibiting the I- migration. Arising from the enhanced connection performances, passivated defects, improved perovskite crystallization, enhanced charge extraction, inhibited ions migration, released tensile strain at buried interface by B12H12Cs2, the corresponding devices yield a champion power conversion efficiency of 22.10% with enhanced stability. The stability of devices by B12H12Cs2 modification have been improved, and it can still maintain 72.5% of the original efficiency after 1440 h, while the control devices can only maintain 20% of the original efficiency after aging in air condition of 20-30% RH.

Potassium nitrilotriacetate as a multifunctional modifier of the buried interface for hysteresis-reduced perovskite solar cells.

Potassium nitrilotriacetate (NTAK) was employed to modify the buried SnO2/perovskite interface. Benefiting from the coordination roles of carboxyl and amino groups, and the diffusion role of potassium ions, NTAK could enhance the bilateral connection, improve perovskite morphology, suppress non-radiation recombination, and reduce the hysteresis effect. The optimal device with NTAK modification achieved an effective power conversion efficiency of 21.02%. This was a successful attempt to improve the buried interface.

Enhanced Thermal Stability of Mesoporous Carbon Microbeads-Based Lithium-Ion Batteries by Propargyl Methacrylate as Electrolyte Additive.

In this current work, propargyl methacrylate (PMA) was successfully adopted to be an efficient electrolyte additive to stabilize the formation of a solid electrolyte interface (SEI) layer on mesoporous carbon microbeads (MCMB) in Li-ion batteries, especially at elevated temperatures. According to a series of material and electrochemical characterizations, the optimized concentration of PMA additive in the electrolyte was found to be 0.5 wt.%. The MCMB electrode cycled with the optimized 0.5 wt.% PMA-containing electrolyte exhibited impressive capacity retention of 90.3% after 50 cycles at 0.1C at elevated temperature, which was remarkably higher than that using the PMA-free electrolyte (83.5%). The improved electrochemical stability at elevated temperature could be ascribed to the rapid formation of stable and thin SEI layer on MCMB surface, which were investigated and suggested to be formed via PMA copolymerization reactions.

In situ lead oxysalt passivation layer for stable and efficient perovskite solar cells.

A Rb2SO4 additive is employed to passivate the Pb2+ defects in a perovskite film by forming PbSO4in situ, which can cover the surface and grain boundaries of the perovskite to ensure that the film is not decomposed by moisture. Finally, a device based on the Rb2SO4 modification achieved an enhanced power conversion efficiency (22.25%) and long-term stability.

Analysis of the Oxygen Passivation Effects on MAPbI3 and MAPbBr3 in Fresh and Aged Solar Cells by the Transient Photovoltage Technique.

Previous studies have revealed that for some perovskite compositions, power conversion efficiencies (PCEs) improved after storing the devices in different ambient conditions. With the aim of better understanding such improvements, we focus our attention on the carrier/ionic dynamic kinetics of fresh and aged PSCs with different perovskite compositions (MAPbI3 and MAPbBr3 ) and using spiro-OMeTAD as HTM. For that, we use transient photovoltage (TPV), a technique used to analyse the different recombination kinetics at equilibrium and at different illumination times. We observe that the aging treatment causes significant changes on the kinetics behaviour for bromide-based devices, resulting in a positive influence on the cell performance (from 3.5 % to 6.1 % PCE, in reverse scan). However, the kinetics for those iodide-based perovskite solar cells remains unchangeable (from 16.3 % to 15.0 % PCE, in reverse scan).

The Applications of Polymers in Solar Cells: A Review.

The emerging dye-sensitized solar cells, perovskite solar cells, and organic solar cells have been regarded as promising photovoltaic technologies. The device structures and components of these solar cells are imperative to the device's efficiency and stability. Polymers can be used to adjust the device components and structures of these solar cells purposefully, due to their diversified properties. In dye-sensitized solar cells, polymers can be used as flexible substrates, pore- and film-forming agents of photoanode films, platinum-free counter electrodes, and the frameworks of quasi-solid-state electrolytes. In perovskite solar cells, polymers can be used as the additives to adjust the nucleation and crystallization processes in perovskite films. The polymers can also be used as hole transfer materials, electron transfer materials, and interface layer to enhance the carrier separation efficiency and reduce the recombination. In organic solar cells, polymers are often used as donor layers, buffer layers, and other polymer-based micro/nanostructures in binary or ternary devices to influence device performances. The current achievements about the applications of polymers in solar cells are reviewed and analyzed. In addition, the benefits of polymers for solar cells, the challenges for practical application, and possible solutions are also assessed.

An ultraviolet responsive hybrid solar cell based on titania/poly(3-hexylthiophene).

Here we present an ultraviolet responsive inorganic-organic hybrid solar cell based on titania/poly(3-hexylthiophene) (TiO(2)/P3HT) heterojuction. In this solar cell, TiO(2) is an ultraviolet light absorber and electronic conductor, P3HT is a hole conductor, the light-to-electrical conversion is realized by the cooperation for these two components. Doping ionic salt in P3HT polymer can improve the photovoltaic performance of the solar cell. Under ultraviolet light irradiation with intensity of 100 mW·cm(-2), the hybrid solar cell doped with 1.0 wt.% lithium iodide achieves an energy conversion efficiency of 1.28%, which is increased by 33.3% compared to that of the hybrid solar cell without lithium iodide doping. Our results open a novel sunlight irradiation field for solar energy utilization, demonstrate the feasibility of ultraviolet responsive solar cells, and provide a new route for enhancing the photovoltaic performance of solar cells.

Dual functions of YF3:Eu³âº for improving photovoltaic performance of dye-sensitized solar cells.

In order to enhance the photovoltaic performance of dye-sensitized solar cell (DSSC), a novel design is demonstrated by introducing rare-earth compound europium ion doped yttrium fluoride (YF3:Eu³âº) in TiO2 film in the DSSC. As a conversion luminescence medium, YF3:Eu³âº transfers ultraviolet light to visible light via down-conversion, and increases incident harvest and photocurrent of DSSC. As a p-type dopant, Eu³âº elevates the Fermi level of TiO2 film and thus heightens photovoltage of the DSSC. The conversion luminescence and p-type doping effect are demonstrated by photoluminescence spectra and Mott-Schottky plots. When the ratio of YF3:Eu³âº/TiO2 in the doping layer is optimized as 5 wt.%, the light-to-electric energy conversion efficiency of the DSSC reaches 7.74%, which is increased by 32% compared to that of the DSSC without YF3:Eu³âº doping. Double functions of doped rare-earth compound provide a new route for enhancing the photovoltaic performance of solar cells.

Glucose aided preparation of tungsten sulfide/multi-wall carbon nanotube hybrid and use as counter electrode in dye-sensitized solar cells.

The tungsten sulfide/multi-wall carbon nanotube (WS(2)/MWCNT) hybrid was prepared in the presence of glucose by the hydrothermal route. The hybrid materials were used as counter electrode in the dye-sensitized solar cell (DSSC). The results of cyclic voltammetry measurement and electrochemical impedance spectroscopy indicated that the glucose aided prepared (G-A) WS(2)/MWCNT electrode had low charge-transfer resistance (R(ct)) and high electrocatalytic activity for triiodide reduction. The excellent electrochemical properties for (G-A) WS(2)/MWCNT electrode is due to the synergistic effects of WS(2) and MWCNTs, as well as amorphous carbon introduced by glucose. The DSSC based on the G-A WS(2)/MWCNT counter electrode achieved a high power conversion efficiency of 7.36%, which is comparable with the performance of the DSSC using Pt counter electrode (7.54%).

Application of Y(2)O(3):Er(3+) nanorods in dye-sensitized solar cells.

Y(2)O(3):Er(3+) nanorods are synthesized by means of a hydrothermal method and then introduced into a TiO(2) electrode in a dye-sensitized solar cell (DSSC). Y(2)O(3):Er(3+) improves infrared light harvest via up-conversion luminescence and increases the photocurrent of the DSSC. The rare earth ions improve the energy level of the TiO(2) electrode through a doping effect and thus increase the photovoltage. The light scattering is ameliorated by the one-dimensional nanorod structure. The DSSC containing Y(2)O(3):Er(3+) (5 wt%) in the doping layer achieves a light-to-electric energy conversion efficiency of 7.0%, which is an increase of 19.9% compared to the DSSC lacking of Y(2)O(3):Er(3+).

A large-area light-weight dye-sensitized solar cell based on all titanium substrates with an efficiency of 6.69% outdoors.

Light-weight PEDOT-Pt/Ti mesh and Ti/TiO(2) foil electrodes are prepared. Owing to the PEDOT-Pt/Ti photocathode's high transparency, good electrocatalytic activity, and low resistance; the Ti/TiO(2) anode's large specific area and high conductivity, a light-weight backside illuminated large-area (100 cm(2) ) dye-sensitized solar cell achieves an energy conversion efficiency of 6.69% under an outdoors sunlight irradiation of 55 mW cm(-2) .