Chemical bath deposition of SnOfilms on PEN/ITO substrates for efficient flexible perovskite solar cells.

Flexible perovskite solar cells (f-PSCs) have achieved significant success. However, high-quality tin dioxide (SnO) electron transport layers (ETLs) fabricated via chemical bath deposition (CBD) have not been achieved on flexible PEN/ITO substrates. This limitation is primarily due to the corrosion of the poor-quality ITO layer by the strongly acidic CBD solution.

Perovskite solar cells based on screen-printed thin films.

One potential advantage of perovskite solar cells (PSCs) is the ability to solution process the precursors and deposit films from solution. At present, spin coating, blade coating, spray coating, inkjet printing and slot-die printing have been investigated to deposit hybrid perovskite thin films. Here we expand the range of deposition methods to include screen-printing, enabled by a stable and viscosity-adjustable (40-44,000 cP) perovskite ink made from a methylammonium acetate ionic liquid solvent.

Precursor engineering for efficient and stable perovskite solar cells.

The perovskite film prepared by the two-step spin coating method is widely used in photovoltaic devices due to its good film morphology and great reproducibility. However, there usually exists excessive lead iodide (PbI) in the perovskite film for this method, which is believed to passivate the grain boundaries (GBs) to increase the efficiency of the perovskite solar cells. Nevertheless, the excessive PbIat the GBs of perovskite is believed to induce the decomposition of the perovskite film and undermine the long-term stability of devices.

Vacuum-Assisted Drying Process for Screen-Printable Carbon Electrodes of Perovskite Solar Cells with Enhanced Performance Based on Cuprous Thiocyanate as a Hole Transporting Layer.

Carbon-based perovskite solar cells without a hole transport layer (HTL) are considered to be highly stable and of low cost. However, the deficient interface contact and inferior hole extraction capability restrict the further improvement of the device efficiency. Introducing a hole transporting layer, such as cuprous thiocyanate (CuSCN), can enhance the hole extraction ability and improve the interface contact.

Impact of the Inflow Population From Outbreak Areas on the COVID-19 Epidemic in Yunnan Province and the Recommended Control Measures: A Preliminary Study.

COVID-19 developed into a global pandemic in 2020 and poses challenges regarding the prevention and control capabilities of countries. A large number of inbound travelers from other regions could lead to a renewed outbreak of COVID-19 in the local regions. Globally, as a result of the imbalance in the control of the epidemic, all countries are facing the risk of a renewed COVID-19 outbreak brought about by travelers from epidemic areas.

CsPbIBr Perovskite Solar Cells Based on Carbon Black-Containing Counter Electrodes.

CsPbIBr perovskite solar cells (PSCs) based on carbon electrodes (CEs) are considered to be low-cost and thermally stable devices. Nevertheless, the insufficient contact and energy level mismatch between the CsPbIBr layer and CE hinder the further enhancement of the cell efficiency. Herein, a carbon black (CB) interlayer was introduced between the perovskite layer and CE.

Effect of Br content on phase stability and performance of HN=CHNHPb(I Br ) perovskite thin films.

Pristine and Br-doped HN = CHNHPb(I Br ) (FAPb(I Br ), Br content x = 0, 0.05, 0.15, 0.

Influence of hole transport material/metal contact interface on perovskite solar cells.

Interfaces have a significant impact on the performance of perovskite solar cells. This work investigated the influence of hole transport material/metal contact interface on photovoltaic behaviours of perovskite solar devices. Different hole material/metal contact interfaces were obtained by depositing the metal under different conditions.

Efficient Bulk Heterojunction CHNHPbI-TiO Solar Cells with TiO Nanoparticles at Grain Boundaries of Perovskite by Multi-Cycle-Coating Strategy.

A novel bulk heterojunction (BHJ) perovskite solar cell (PSC), where the perovskite grains act as donor and the TiO nanoparticles act as acceptor, is reported. This efficient BHJ PSC was simply solution processed from a mixed precursor of CHNHPbI (MAPbI) and TiO nanoparticles. With dissolution and recrystallization by multi-cycle-coating, a unique composite structure ranging from a MAPbI-TiO-dominated layer on the substrate side to a pure perovskite layer on the top side is formed, which is beneficial for the blocking of possible contact between TiO and the hole transport material at the interface.

Fast Fabrication of a Stable Perovskite Solar Cell with an Ultrathin Effective Novel Inorganic Hole Transport Layer.

With the aim of fabricating simple, reproducible, and scalable perovskite solar cells (PSCs) with least time consumption, a novel CoO hole transport layer (HTL) was first proposed and introduced in this work. The CoO HTL thickness was minimized to about 10 nm with complete coverage on the FTO substrate (F-doped SnO) by direct current magnetron sputtering. The ultrathin HTL could minimize the incident light loss caused by cobalt ion absorption and reduce the carrier transport loss by shortening the transport path.

Enhanced electrical property of Ni-doped CoO hole transport layer for inverted perovskite solar cells.

Ultrathin Ni doped CoO films were prepared by direct current co-sputtering at room temperature as inorganic hole transport materials for inverted perovskite solar cells. P-type doping was designed to adjust the valence band position of CoO to match the that of CHNHPbI, which would effectively eliminate the interface barrier. Moreover, the hole extraction ability would be enhanced and the power conversion efficiency of the devices hence increased from 3.

Nucleation mediated interfacial precipitation for architectural perovskite films with enhanced photovoltaic performance.

Perovskite films are a promising candidate for future highly efficient and low-cost solar cells. The long diffusion length of charge carriers in the perovskite film makes its architecture fabrication seem unnecessary, while the rapid crystallization process increases the difficulty in its architecture fabrication. Here we show the fabrication of perovskite architectures through a nucleation mediated interfacial precipitation method with the proper immiscible anti-solvent.

Ultrasmooth Perovskite Film via Mixed Anti-Solvent Strategy with Improved Efficiency.

Most antisolvents employed in previous research were miscible with perovskite precursor solution. They always led to fast formation of perovskite even if the intermediate stage existed, which was not beneficial to obtain high quality perovskite films and made the formation process less controllable. In this work, a novel ethyl ether/n-hexane mixed antisolvent (MAS) was used to achieve high nucleation density and slow down the formation process of perovskite, producing films with improved orientation of grains and ultrasmooth surfaces.

Achieving High Current Density of Perovskite Solar Cells by Modulating the Dominated Facets of Room-Temperature DC Magnetron Sputtered TiO Electron Extraction Layer.

The short circuit current density of perovskite solar cell (PSC) was boosted by modulating the dominated plane facets of TiO electron transport layer (ETL). Under optimized condition, TiO with dominant {001} facets showed (i) low incident light loss, (ii) highly smooth surface and excellent wettability for precursor solution, (iii) efficient electron extraction, and (iv) high conductivity in perovskite photovoltaic application. A current density of 24.

Mesostructured perovskite solar cells based on highly ordered TiO network scaffold via anodization of Ti thin film.

An anodized TiO interconnected network was fabricated and utilized as a mesoporous scaffold and electron transporter in perovskite solar cells. By modifying the synthesis parameters, the morphological features of the interconnected TiO nanostructures can be widely tuned and precisely controlled. The functional properties of the anodized TiO network are found to be severely influenced by morphology as well as the extent of oxidation.

One step spray-coated TiO electron-transport layers for decent perovskite solar cells on large and flexible substrates.

Spray-coating as a facile and quantitative method was introduced to prepare thin and continuous TiO compact layers on different substrates for perovskite solar cells. The as-prepared film is highly transparent and smooth, which is of significance in perovskite solar cells to decrease incident light loss and facilitate the film cast and electric contact. The compact TiO layer shows excellent performance when coated with perovskite and assembled into a device.

Fast and Controllable Crystallization of Perovskite Films by Microwave Irradiation Process.

The crystal growth process significantly influences the properties of organic-inorganic halide perovskite films along with the performance of solar cell devices. In this paper, we adopted the microwave irradiation to treat perovskite films through a one-step deposition method for several minutes at a fixed output power. It is found that the specific microwave irradiation process can evaporate the solvent directly and heat perovskite film quickly.

Template-free synthesis of hierarchical TiO2 structures and their application in dye-sensitized solar cells.

We demonstrate here the synthesis of a hierarchical TiO(2) architecture without any surfactants or templates. Two kinds of structure existed simultaneously, the ordered nanoarrays at bottom provided direct conduction pathway for photo generated electrons, while the upper micro-flowers consisted of nanobelt as building units increased the light harvesting ability as the scattering part. The formation mechanism of the hierarchical architecture has been proposed by studying the morphology evolution processes upon reaction time.

A general precipitation strategy for large-scale synthesis of molybdate nanostructures.

A general precipitation strategy has been developed for the large-scale synthesis of molybdate nanostructures, and a series of molybdate nanostructures such as Fe(2)(MoO(4))(3) nanoparticles, ZnMoO(4) nanoplates, MnMoO(4) nanorods and CoMoO(4) nanowires have been successfully prepared.

Synthesis and magnetic properties of Co-Sn-O nanorings.

A novel Co-Sn-O nanoring structure was synthesized via a simple hydrothermal route; the difference in diffusion rates of ions was considered to be the main reason for the formation of such a ring structure.

Fabrication of well-defined water-soluble core/shell heteronanostructures through the SiO2 spacer.

A generalized approach for the fabrication of core/shell heteronanostructures through a simple chemical bath deposition method assisted by the bridging of SiO(2) spacer has been developed and a slow heterogeneous nucleation mechanism identified as the key to the success of this method.

Controlled synthesis and self-assembly of CeO2 nanocubes.

CeO2 nanocubes (and nanorods) enclosed by six {200} planes with controlled sizes have been prepared through a facile one-pot method. The nanocubes have a strong tendency to assemble into 2D and 3D arrays with regular patterns on a substrate, which is probably driven by the dipole-dipole interaction of polar {200} planes. The possible formation mechanism of the nanocubes has been put forward as the oriented aggregation mediated precursor growth.