Direct Integration of Perovskite Solar Cells with Carbon Fiber Substrates.

Integrating photovoltaic devices onto the surface of carbon-fiber-reinforced polymer substrates should create materials with high mechanical strength that are also able to generate electrical power. Such devices are anticipated to find ready applications as structural, energy-harvesting systems in both the automotive and aeronautical sectors. Here, the fabrication of triple-cation perovskite n-i-p solar cells onto the surface of planarized carbon-fiber-reinforced polymer substrates is demonstrated, with devices utilizing a transparent top ITO contact.

Nonplanar Spray-Coated Perovskite Solar Cells.

Spray coating is an industrially mature technique used to deposit thin films that combines high throughput with the ability to coat nonplanar surfaces. Here, we explore the use of ultrasonic spray coating to fabricate perovskite solar cells (PSCs) over rigid, nonplanar surfaces without problems caused by solution dewetting and subsequent "run-off". Encouragingly, we find that PSCs can be spray-coated using our processes onto glass substrates held at angles of inclination up to 45° away from the horizontal, with such devices having comparable power conversion efficiencies (up to 18.

Gas-Assisted Spray Coating of Perovskite Solar Cells Incorporating Sprayed Self-Assembled Monolayers.

Self-assembled monolayers (SAMs) are becoming widely utilized as hole-selective layers in high-performance p-i-n architecture perovskite solar cells. Ultrasonic spray coating and airbrush coating are demonstrated here as effective methods to deposit MeO-2PACz; a carbazole-based SAM. Potential dewetting of hybrid perovskite precursor solutions from this layer is overcome using optimized solvent rinsing protocols.

Perovskites on Ice: An Additive-Free Approach to Increase the Shelf-Life of Triple-Cation Perovskite Precursor Solutions.

Invited for this month's cover is the group of David Lidzey at the University of Sheffield. The image shows a futuristic view of large-scale perovskite solar cell (PSC) manufacture. This includes a high-volume roll-to-roll printing facility and cold-storage of PSC precursor solutions in large industrial fridges.

Perovskites on Ice: An Additive-Free Approach to Increase the Shelf-Life of Triple-Cation Perovskite Precursor Solutions.

The development of stable perovskite precursor solutions is critical if solution-processable perovskite solar cells (PSCs) are to be practically manufacturable. Ideally, such precursors should combine high solution stability without using chemical additives that might compromise PSC performance. Here, it was shown that the shelf-life of high-performing perovskite precursors could be greatly improved by storing solutions at low-temperature without the need to alter chemical composition.

Potassium iodide reduces the stability of triple-cation perovskite solar cells.

The addition of alkali metal halides to hybrid perovskite materials can significantly impact their crystallisation and hence their performance when used in solar cell devices. Previous work on the use of potassium iodide (KI) in active layers to passivate defects in triple-cation mixed-halide perovskites has been shown to enhance their luminescence efficiency and reduce current-voltage hysteresis. However, the operational stability of KI passivated perovskite solar cells under ambient conditions remains largely unexplored.

Rapid Scalable Processing of Tin Oxide Transport Layers for Perovskite Solar Cells.

The development of scalable deposition methods for perovskite solar cell materials is critical to enable the commercialization of this nascent technology. Herein, we investigate the use and processing of nanoparticle SnO films as electron transport layers in perovskite solar cells and develop deposition methods for ultrasonic spray coating and slot-die coating, leading to photovoltaic device efficiencies over 19%. The effects of postprocessing treatments (thermal annealing, UV ozone, and O plasma) are then probed using structural and spectroscopic techniques to characterize the nature of the np-SnO/perovskite interface.

Manipulating Crystallization of Organolead Mixed-Halide Thin Films in Antisolvent Baths for Wide-Bandgap Perovskite Solar Cells.

Wide-bandgap perovskite solar cells (PSCs) based on organolead (I, Br)-mixed halide perovskites (e.g., MAPbI2Br and MAPbIBr2 perovskite with bandgaps of 1.

Pt- and TCO-Free Flexible Cathode for DSSC from Highly Conducting and Flexible PEDOT Paper Prepared via in Situ Interfacial Polymerization.

Here, we report the preparation of a flexible, free-standing, Pt- and TCO-free counter electrode in dye-sensitized solar cell (DSSC)-derived from polyethylenedioxythiophene (PEDOT)-impregnated cellulose paper. The synthetic strategy of making the thin flexible PEDOT paper is simple and scalable, which can be achieved via in situ polymerization all through a roll coating technique. The very low sheet resistance (4 Ω/□) obtained from a film of 40 μm thick PEDOT paper (PEDOT-p-5) is found to be superior to the conventional fluorine-doped tin oxide (FTO) substrate.

Microstructures of Organometal Trihalide Perovskites for Solar Cells: Their Evolution from Solutions and Characterization.

The use of organometal trihalide perovskites (OTPs) in perovskite solar cells (PSCs) is revolutionizing the field of photovoltaics, which is being led by advances in solution processing of OTP thin films. First, we look at fundamental phenomena pertaining to nucleation/growth, coarsening, and microstructural evolution involved in the solution-processing of OTP thin films for PSCs from a materials-science perspective. Established scientific principles that govern some of these phenomena are invoked in the context of specific literature examples of solution-processed OTP thin films.

Intercalation crystallization of phase-pure α-HC(NH₂)₂PbI₃ upon microstructurally engineered PbI₂ thin films for planar perovskite solar cells.

The microstructure of the solid-PbI2 precursor thin film plays an important role in the intercalation crystallization of the formamidinium lead triiodide perovskite (α-HC(NH2)2PbI3). It is shown that microstructurally engineered PbI2 thin films with porosity and low crystallinity are the most favorable for conversion into uniform-coverage, phase-pure α-HC(NH2)2PbI3 perovskite thin films. Planar perovskite solar cells fabricated using these thin films deliver power conversion efficiency (PCE) up to 13.

Dramatic Enhancement in Photoresponse of β-In2S3 through Suppression of Dark Conductivity by Synthetic Control of Defect-Induced Carrier Compensation.

We report on the synthesis of dense and faceted indium sulfide (β-In2S3) nano-octahedron films on fluorine-doped tin oxide-coated glass by the hydrothermal method and their photoresponse properties in a flip chip device configuration. We have examined the temporal evolution of the phase constitution, morphology, and optoelectronic properties for films obtained after growth interruption at specific intervals. It is noted that, initially, an In(OH)3 film forms, which is gradually transformed to the β-In2S3 phase over time.

Enhanced catalytic activity of polyethylenedioxythiophene towards tri-iodide reduction in DSSCs via 1-dimensional alignment using hollow carbon nanofibers.

Here, we report a highly conducting 1-dimensionally (1-D) aligned polyethylenedioxythiophene (PEDOT) along the inner and outer surfaces of a hollow carbon nanofiber (CNF) and its application as a counter electrode in a dye sensitized solar cell (DSSC). The hybrid material (CP-25) displays a conversion efficiency of 7.16% compared to 7.

CH₃NH₃PbI(3-x)(BF₄)x: molecular ion substituted hybrid perovskite.

A molecular ion (BF4(-)) substituted hybrid perovskite CH3NH3PbI(3-x)(BF4)x is synthesized. The substituted perovskite shows significant enhancement in electrical conductivity at low frequencies and improved photoresponse under AM1.5 illumination as compared to the perovskite (CH3NH3PbI3).

ZnO(N)-Spiro-MeOTAD hybrid photodiode: an efficient self-powered fast-response UV (visible) photosensor.

Organic-inorganic hybrid photo-detectors with a self-sufficient mode of operation represent a research area of great current interest. In most efficient photodetectors and optoelectronic devices compound semiconductors containing toxic elements such as Cd, As, Te, S, Se etc. are used and these are also expensive.

Citrate milling of oxides: from poly-dispersed micron scale to nearly mono-dispersed nanoscale.

Complex (multivalent/mixed valent) oxides involving two or more cations (e.g. ABO3, AB2O4 and A2B2O7) exhibit the most fascinating range of physical and chemical properties amongst the family of materials systems.

Strong photo-response in a flip-chip nanowire p-Cu2O/n-ZnO junction.

Cu(2)O nanoneedles are synthesized on a copper substrate by a simple anodization and reducing ambient annealing protocol. ZnO nanorods are grown on ITO coated glass by a low temperature chemical route. The electronic and photo-response properties of the p-Cu(2)O/n-ZnO flip-chip heterojunction are then studied and analyzed.