With rapid and brilliant progress in performance over recent years, perovskite solar cells have drawn increasing attention for portable power source applications.

Inorganic/organic nanocomposite counter electrodes comprised of sheetlike CoS nanoparticles dispersed in polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene (CoS/PEDOT:PSS) offer a synergistic effect on catalytic performance toward the reduction of triiodide for dye-sensitized solar cells (DSSCs), yielding 5.4% power conversion efficiency, which is comparable to that of the conventional platinum counter electrode (6.1%). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry measurements revealed that the composite counter electrodes exhibited better catalytic activity, fostering rate of triiodide reduction, than that of pristine PEDOT: PSS electrode. The simple preparation of composite (CoS/PEDOT:PSS) electrode at low temperature with improved electrocatalytic properties are feasible to apply in flexible substrates, which is at most urgency for developing novel counter electrodes for lightweight flexible solar cells.

A simple, low-cost, large area, and continuous scalable coating method is proposed for the fabrication of hybrid organic-inorganic perovskite solar cells. A megasonic spray-coating method utilizing a 1.7 MHz megasonic nebulizer that could fabricate reproducible large-area planar efficient perovskite films is developed. The coating method fabricates uniform large-area perovskite film with large-sized grain since smaller and narrower sized mist droplets than those generated by existing ultrasonic spray methods could be generated by megasonic spraying. The volume flow rate of the CH 3 NH 3 PbI 3 precursor solution and the reaction temperature are controlled, to obtain a high quality perovskite active layer. The devices reach a maximum efficiency of 16.9%, with an average efficiency of 16.4% from 21 samples. The applicability of megasonic spray coating to the fabrication of large-area solar cells (1 cm 2 ), with a power conversion efficiency of 14.2%, is also demonstrated. This is a record high efficiency for large-area perovskite solar cells fabricated by continuous spray coating. Perovskite Solar Cells www.advancedsciencenews.com

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Herein, we developed a novel electrospray coating system for continuous fabrication of perovskite solar cells with high performance. Our system can systemically control the size of CHNHPbI precursor droplets by modulating the applied electrical potential, shown to be a crucial factor for the formation of perovskite films. As a result, we have obtained pinhole-free and large grain-sized perovskite solar cells, yielding the best PCE of 13.27% with little photocurrent hysteresis. Furthermore, the average PCE through the continuous coating process was 11.56 ± 0.52%. Our system demonstrates not only the high reproducibility but also a new way to commercialize high-quality perovskite solar cells.

Even though the solid polymer electrolyte has many intrinsic advantages over the liquid electrolyte, its ionic conductivity and mesopore-filling are much poorer than those of the liquid electrolyte, limiting its practical application to electrochemical devices such as dye-sensitized solar cells (DSCs). Two major shortcomings associated with utilizing solid polymer electrolytes in DSCs are first discussed, low ionic conductivity and poor pore-filling in mesoporous photoanodes for DSCs. In addition, future directions for the successful utilization of solid polymer electrolytes toward improving the performance of DSCs are proposed. For instance, the facilitated mass-transport concept could be applied to increase the ionic conductivity. Modified biphasic and triple-phasic structures for the photoanode are suggested to take advantage of both the liquid- and solid-state properties of electrolytes.

The effects on the photovoltaic performance of the incorporation of SnO2 nanoparticles into the polymer of a solid-state dye-sensitized solar cell (DSC) based on the poly(ethylene oxide)/poly(ethylene glycol) dimethyl ether solid electrolyte are studied in this paper. It has been found that the addition of SnO2 nanoparticles to the solid electrolyte produces several key changes in the properties of the solid-state DSC that produced a better performance of the device. Therefore, we have measured an improvement in electrolyte conductivity by a factor of 2, a linear rise in the TiO2 conduction band position, a reduction in the electron recombination rate, and a decrease in charge-transfer resistance at the counterlectrode/electrolyte interface. All these improvements produced an increase in the power conversion efficiency from 4.5 to 5.3% at 1 sun condition, a consequence of the increase of both V oc (oc = open circuit) and J sc (sc = short circuit) without any sacrifice in FF (fill factor). The origin of these changes has been associated to the strong Lewis acidic character of SnO2 nanoparticles yielding to the formation of a I3 – percolation layer for holes at the surface of SnO2 and the reduction of the concentration of free I3 – and K+ ions inside the pores of TiO2. From these results, it is concluded that the physicochemical effects of inorganic nanofiller in the polymer electrolyte may also be considered a good route in designing the high efficiency solid-state DSCs employing the polymer electrolyte.

A novel poly(ethylene glycol) (PEG) based oligomeric coadsorbent was employed to passivate TiO 2 photoanodes resulting in the large increase in both opencircuit voltage (V oc ) and short-circuit current density (J sc ) primarily because of the reduced electron recombination by the effective coverage of vacant sites as well as the negative band-edge shift of TiO 2 . The effective suppression of electron recombination was evidenced by electrochemical impedance spectroscopy (EIS) and by stepped light-induced transient measurements of photocurrent and voltage (SLIM-PCV). The work function measurements also showed that the existence of coadsorbents on TiO 2 interfaces is capable of shifting the band-edge of TiO 2 photoanodes upwardly resulting in the increase in photovoltage. In addition, the coadsorbent was proven to be effective even in the presence of common additives such as LiI, 4-tert-butylpyridine, and guanidinium thiocyanate. The effect of Li + cation trapping by ethylene oxide units of the coadsorbent was particularly notable to significantly increase V oc at a small expense of J sc . Consequently, the introduction of novel PEG-based oligomeric coadsorbents for TiO 2 photoanodes is quite effective in the improvement of photovoltaic performance because of the simultaneous increase in both V oc and J sc .