Materials Science Resources

Cyclic voltammetry is an electrochemical technique for measuring the current response of a redox active solution to a linearly cycled potential sweep between two or more set values.

Over the past 10 years, perovskite solar cells (PSCs) have achieved record efficiencies of 25.5% single junction solar cells (as of 20211) and these efficiencies are rising impressively.

Cyclic voltammetry is a versatile electrochemical method with a range of different applications. In cyclic voltammetry, each successful forwards and backwards potential sweep produces a 'duck-shaped' plot known as a cyclic voltammogram.

A perovskite solar cell is a thin film photovoltaic device. In these devices, perovskites absorb sunlight and convert it into electrical energy. Certain perovskites have fundamental properties which make them excellent at this. In some ways, perovskites are even better than the materials used in current solar cells.

Cyclic voltammetry is a powerful and versatile electrochemical technique. With modern potentiostats and software packages, the method is relatively straight-forward to perform. Despite this apparent simplicity, there are still a number of things that can go wrong, particularly when setting up the electrochemical cell.

Potentiostats are voltage sources that vary their output potential in response to changes in the resistance across the circuit.

Glove boxes create a stable, sealed environment for handling hazardous materials, chemicals, or samples that react readily with air. Samples can be transferred into the glove box via the glove box antechamber, and glove box gloves can be used to manipulate the contents of the glove box.

When buying a glove box, it's important that you choose the most suitable system for your specific lab and experiments. The first question that you should be asking yourself when looking for a glove box is what do I need?

The Ossila Glove Box is designed to be easy to install and maintain, and is suitable for most laboratories. Its small footprint and quick set up also means that it is relatively portable and can be conveniently transferred between labs as required.

Air free techniques are essential for the handling and storage of materials that are unstable when exposed to air. Compounds are defined as unstable if they react with an element in air, often moisture or oxygen.

Inert gases are gases which are chemically inactive, so will not undergo chemical reactions with many materials. Inert gases are used for many purposes in a wide range of industries - for example in welding, chemical processing, and as filler gases in light sources.

Argon and nitrogen are both unreactive gases which can be used to create an inert environment within a glove box. Both gases will efficiently displace air within a confined space, are easy to store and will not react with most materials. Therefore, both N2 and Ar can create a glove box environment with very low moisture and oxygen levels.

The Ossila Glove Box (or glovebox) uses automatic purging and programmable leak tests making it easy to maintain an inert environment. However, there are a number of steps that you as the glove box user can take to ensure that the inert atmosphere remains intact.

Scientific glove boxes create a sealed environment for work that involves hazardous materials or samples that react with air. The main chamber of such a glove box is generally filled with an inert gas, usually Nitrogen.

The most common cause of glove box leaks is human error, either as a result of not following operating procedures correctly or from accidental damage. In terms of physical damage, the most likely puncture points will be the glove box gloves or the seals around the antechamber doors.

Glove box gloves must be flexible and relatively thin. This allows for movement within the main chamber. The gloves will be the most vulnerable exposure point to air and moisture in your glove box as small holes can easily occur.

Laminar flow is a concept in fluid dynamics which describes the smooth and orderly movement of a fluid (liquid or gas). In laminar flow, fluid particles move in predictable, parallel layers with minimal mixing between layers.

Laminar flow hoods (LFH) are essential tools used in scientific and industrial settings to create a controlled, clean environment for various applications.

In lab environments, both laminar flow hoods and fume hoods operate to provide workspaces with enhanced ventilation and filtration mechanisms.

When working in laboratories, ensuring a safe and clean environment is paramount. Biological Safety Cabinets and Laminar Flow Hoods are two units that can be used to achieve these standards.

In settings and applications where a clean environment is essential, laminar flow hoods (LFHs) are a vital tool. Use of a LFH ensures a contamination-free workspace by generating a continuous flow of clean air to remove airborne particles.

Ossila laminar flow hoods are designed for effortless setup, user-friendly operation, and efficient control. This short video guide shows you how to get started with your new equipment.

The acronym HEPA stands for High Efficiency Particulate Air, and these filters boast an exceptional ability to achieve a high standard of particle filtration.

High Efficiency Particulate Air (HEPA) filters are designed to efficiently remove airborne particles and contaminants, making them indispensable tools in laboratories and cleanroom facilities.

Ultra-Low Particulate Air (ULPA) and High-Efficiency Particulate Air (HEPA) filters are both used in laminar flow hoods to remove particles from incoming air.

Regular and thorough cleaning of your laminar flow hood allows you to reliably conduct your experiments without risk of contamination.

Ultraviolet (UV) sterilization is a disinfecting technique that uses UV light to kill or damage microorganisms, such as bacteria, viruses, and fungi.

Laminar flow must be achieved to guarantee air flow will move in a single direction and ensure optimal performance of the hood. This is needed to achieve the clean air functions listed above.

Spin coating is a common technique for applying thin films to substrates. When a solution of a material and a solvent is spun at high speeds, the centripetal force and the surface tension of the liquid together create an even covering.

Dip coating is a simple and effective technique which is commonly used in manufacturing across a wide range of different industries. Within research and development, it has become an important coating method for the fabrication of thin films using a purpose-built dip coater.

Linear sweep voltammetry (LSV) is a simple electrochemical technique. The method is similar to cyclic voltammetry, but rather than linearly cycling over the potential range in both directions, linear sweep voltammetry involves only a single linear sweep from the lower potential limit to the upper potential limit.

When it comes to depositing highly-uniform wet thin films, there are many different solution-processing techniques capable of producing high-quality films at low cost.

This guide will explain what a contact angle is and how it is measured. It will also show you how the Ossila Contact Angle Goniometer works and how to get the best measurement results.

Surface free energy is a measure of the excess energy present at the surface of a material, in comparison to at its bulk. It can be used to describe wetting and adhesion between materials.

Surface wetting occurs when a droplet spreads out over a surface, such that its contact angle is below 90°. When the droplet spreads out completely, this angle will be 0°, and 'complete wetting' will have occurred.

In this guide we will use the Ossila Contact Angle software to measure a droplet on an uneven surface.

GUIDE

With no external dependencies, the Ossila Syringe Pump is quick and easy to set up and use.

Syringe pumps, or syringe drivers, are motorised devices that accurately control the movement of a fluid from a syringe by mechanically inserting or retracting the plunger. Syringe pumps feature stepper motors which can accurately move a platform attached to the plunger of a syringe.

Syringe pumps are electromechanical devices which are designed to convert rotational motion to linear motion. This linear motion can then be used to drive the plunger of a syringe and deliver a precise amount of solution.

Syringe pumps provide precise control over the movement and delivery of fluids and can be incorporated into a wide range of experimental setups to ensure that any work done is reproducible and accurate.

When auto dispensing solvents, droplets are sometimes dispensed after the syringe pump has stopped. The cause of solution dripping can be due to several factors.

A spectrometer is a device that measures a continuous, non-discrete physical characteristic by first separating it into a spectrum of its constituent components.

Optical spectrometers take light and separate it by wavelength to create a spectra which shows the relative intensity of each. This basic principle has a wide range of applications and uses.

Spectrometers can be designed and built using a number of different optical configurations. Careful choice of components and configuration can avoid aberrations, which result in distorted or blurred spectra.

It can be incredibly frustrating if you encounter a problem while performing UV-Vis spectroscopy, and usually causes an unnecessary delay.

Like any analytical technique, spectrometers are subject to error, including dark noise, stray light, and spectral bandwidth.

When an electron is excited into a higher energy state, either through absorption of a photon or another excitation method, this creates a positively charged space in the lower energy leel known as a "hole."

Solar irradiance varies depending on where you are in the world. This is because of a combination of local atmospheric conditions and geometric considerations.

The purpose of a solar simulator is to recreate the sunlight received on Earth. This is easier said than done as sunlight starts its journey in complex nuclear reactions in the sun's core, and is modified on it's journey to us through interactions with the Earth's atmosphere.

Light can be measured either photometrically (only light visible to the human eye is considered) or radiometrically (also considers the energy in the invisible parts of the electromagnetic spectrum).

New developments in solar cell technology have enabled the realisation of flexible solar cells, the applications of which can be utilized in more imaginative ways than ever before.

A solar simulator has several components that help to simulate the solar spectrum uniformly for a defined test area. The most important part of the several components is the light source, however the other components ensure the light source outputs the solar spectrum correctly.

The solar simulator light source is compact, lightweight and can be easily installed in any lab using adjustable height stand provided with it.

This system was designed to be easy to use, and effortless to assemble. This video and subsequent guide will demonstrate how easy setting up your testing lab can be with the Ossila Automated Solar Cell Testing Bundle.

It is important to ensure that your solar simulator is outputting a consistent spectral output. Different solar simulators will have different bulb lifetimes.

Solar simulators must be evaluated according to one of the three standards, and comply with the specifications set out within.

Solar simulators generally attempt to replicate the standard AM1.5G spectrum which has a total integrated irradiance of 1000.4 W/m2 over the wavelength range of 280 nm – 4000 nm.

One main application of solar simulators is to test solar cell devices and modules. To characterise how solar cells will perform in the real world, it is vital that you use a solar source that mimics the suns spectrum well. You could of course use actual sunlight, but this is an uncontrollable variable.

When it comes to testing the performance of solar cells, accurate measurements and reliable equipment are essential. If you are conducting research into PV materials, understanding how to measure and interpret J-V curves is crucial in assessing device performance

Anaylzing key device metrics such as fill factor (FF), open-circuit voltage (V_OC), and power conversion efficiency (PCE), can help you find potential issues with your solar cell devices

Choosing the right light source for your solar simulator is one the most important decisions to make when setting up a PV testing laboratory

Optical spectroscopy (or UV-Vis spectroscopy) is a versatile and non-invasive technique that can be used to study a wide range of materials.

Spectroscopy can be performed using a range of different light sources. These can typically be categorised as being either monochromatic or broadband.

Jablonski diagrams are the simplest way to the transitions between electronic and vibrational states. The representative energy levels are arranged with energy on the vertical axis and vary horizontally according to energy state multiplicity.

Optical spectroscopy data can be processed faster and more consistently using programming tools such as Python. This is a step-by-step guide of how researchers process multiple spectra that were taken using the Ossila Optical Spectrometer. The code in this guide is designed for the Ossila Optical Spectrometer.

Data can be easily plotted using the following Python code to plot data using Pandas DataFrame.Just copy and paste the code below into your Python virtual environment and start plotting.

Spectroscopy is an invaluable technique used to study the interaction between radiative energy and matter. Different types of radiative energy used in spectroscopy include electrons, neutrons, ions, and acoustic waves.

Both fluorescence and phosphorescence are types of photoluminescence. Photoluminescence refers to radiative emissions where the absorbance of a photon is followed by the emission of a lower energy photon. The main empirical difference between fluorescence and phosphorescence is the time in between absorbance and the emission of photons.

The blazed diffraction grating is a type of grating that has a "sawtooth" profile. Blazed diffraction gratings will maximise the grating efficiency in one desired diffraction order at a specific wavelength, while other orders are minimised.

This article contains some advice from our researchers that should help you get started taking optical spectroscopy measurements of thin films.

To measure the fluorescence of a thin film, you will need an optical spectrometer, a fixed sample holder and a high energy light source (such as a UV laser or the Ossila UV light source). We also recommend using optical fiber cables between modular elements to reduce the attenuation of your signal.

Optical fibers (or fiber optic cables) are cables which transmit light efficiently along an extremely thin glass (silica) or plastic fiber. Light travels down the cable due to total internal reflection.

Electroluminescence (EL) is the generation of light through the radiative recombination of holes and electrons which have been injected into the material from cathode and anode contacts. The charge carriers are injected into the material due to an applied bias over the cathode and anode. These cathode and anodes are orientated opposite each other.

The different types of spectroscopy can be categorised by either the application it is used for or by type of radiative energy employed. The application of spectroscopic methods in organic (carbon-based) chemistry and organic electronics is known as organic spectroscopy.

In absorption spectroscopy, the intensity of light absorbed by a sample is measured as a function of wavelength. This can provide important information about the electronic structure of an atom or molecule.

You should not be measuring negative absorbance values for any sample. Absorbance measurements come from transmission measurements where light that passes through your sample is collected by the spectrometer (or spectrophotometer) and compared to a reference spectrum.

Photoluminescence is luminescence resulting from photoexcitation. In other words, photoluminescence is when a material emits light following the absorption of energy from incident light from another light source.

BODIPY is an organic fluorophore with impressive fluorescent quantum yield, small stokes shift and impressive chemical and photostability. These are often used in biological labelling and as an organic fluorescent dye.

Photoluminescence occurs when electrons relax from photoexcited states radiatively. Emissions resulting from singlet-singlet transitions are known as fluorescence. However, there are a number of ways in which electrons in these excited states can relax non-radiatively.

Thermally Activated Delayed Fluorescence (TADF) is a mechanism by which triplet state electrons can be harvested to generate fluorescence.

An exciplex (or excited complex) is a complex formed between two different conjugated molecules (monomers), one of which is in an excited state.

This guide explains the theory behind sheet resistance, an electrical property of thin films of materials, and demonstrates how the four-probe method can be used to measure it.

This guide gives an overview of how to use the Ossila Four-Point Probe System, as well as some general tips and tricks for measuring sheet resistance.

Slot-die coating is an extremely versatile deposition technique in which a solution is delivered onto a substrate via a narrow slot positioned close to the surface.

A solar cell is a device that converts light into electricity via the ‘photovoltaic effect’. They are also commonly called ‘photovoltaic cells’ after this phenomenon, and also to differentiate them from solar thermal devices.

An I-V curve (short for 'current-voltage characteristic curve'), is a graphical representation of the relationship between the voltage applied across an electrical device and the current flowing through it.

Voltammetry is the study of the current response of a chemical under an applied potential difference. Voltammetry encompasses a number of different methods.

Organic photovoltaics (OPVs) have received widespread attention due to promising qualities, such as solution processability, tunable electronic properties, low temperature manufacture, and cheap and light materials.

Due to their high efficiency and well-established manufacture, crystalline silicon (c-Si) solar cells currently dominate the solar cell market.

Whilst the majority of commercial solar cells are currently made using crystalline silicon (c-Si), thin-film alternatives have the potential to be cheaper, flexible, and more straightforward to produce.

Ossila’s pre-patterned ITO substrates are used for a wide variety of teaching and research devices (both organic and inorganic) where a high-quality ITO surface is required.

Whilst organic photovoltaic (OPV) efficiencies have exceeded 14% in research, the majority of proposed systems are small-scale devices manufactured using spin coating which wastes large amounts of materials, and is a batch processing technique.

Whilst efficiencies of lab-scale organic photovoltaic (OPV) cells have continued to rise in recent years, the majority of systems use aromatic halogenated solvents to dissolve the active layer.

When working with air sensitive compounds, it is vital that to protect your materials before removing them from inert atmospheres (like a glove box). One way to do this is to encapsulate your devices before exposing them to ambient conditions.

The rapid improvement of perovskite solar cells has made them the rising star of the photovoltaics world and of huge interest to the academic community.

The discovery of perovskite crystals in the Ural Mountains in the 19th century was followed by the discovery of metal halide perovskites some 50 years later.

This guide describes our recommended fabrication routine for perovskite solar cells using Ossila I101 Perovskite Precursor Ink which is designed to be used with a bottom ITO/PEDOT:PSS anode and a top PC70BM/Ca/Al cathode.

As part of our photovoltaic substrate system, Ossila offers patterned Indium Tin Oxide (ITO) substrates which are designed to work with our evaporation masks to create multi pixel devices.

This article aims to introduce some methods that have been adapted to improve perovskite solar cell stability.

Perovskite solar cells show impressive efficiencies and offer “a different kind of solar cell” that could be cheap to manufacture and could be semi-transparent, lightweight, and flexible.

Perovskite solar cells have demonstrated impressive device metrics, including open-circuit voltages of up to 1.2V. However, in order for PSCs to achieve their theoretical best efficiencies, all non-essential recombination pathways should be eliminated.

Our technical support team receive enquiries about perovskite solar cell or photovoltaic fabrication on a regular basis. For your convenience, we've collated some of the most common questions here which you may find helpful when using I101 or I201 perovskite precursor inks.

The foundation of technology is the understanding of material systems. Specific material properties are required depending on the application.

Carbon nanotubes (CNTs) have been deemed a wonder material due to their remarkable and highly unique physical and chemical properties. They have received much attention over the past decade as a promising material, particularly in the trending field of nanotechnology.

Viscoelastic transfer using polydimethylsiloxane (PDMS) stamps is one of the methods used for the deterministic placement of 2D materials and the fabrication of van der Waals heterostructures.

Molybdenum disulfide belongs to a class of materials called 'transition metal dichalcogenides'. Materials in this class have the chemical formula MX2, where M is a transition metal atom and X is a chalcogen.

Graphene has many potential electronic, optoelectronic and biological uses. However, graphene itself is non-soluble, and this makes it very difficult to deposit from solution.

This guide describes the fabrication of evaporation-free OFETs using the Ossila pre-patterned ITO OFET substrates (product codes S161 & S162).

This guide gives you an overview of what to consider when characterising an OLED, as well as tips for their measurement.

The Ossila Source Measure Unit can be controlled directly over USB or Ethernet using various commands. These can be sent as strings, enabling the use of a large variety of programming languages, including Python, MATLAB, LabVIEW, Java, and C/C++.

The Xtralien Scientific Python distribution is a development environment aimed at scientists and includes all the relevant tools and libraries that a scientist will need to get started.

The X100 (now discontinued, see X200 Source Measure Unit instead) is a powerful and versatile device. The tutorials and demos on this page are intended to help get you started with the X100 and make device characterisation as easy as possible.

The acronym ‘OLED’ stands for Organic Light-Emitting Diode - a technology that uses LEDs in which the light is produced by organic molecules. These organic LEDs are used to create what are considered to be the world’s best display panels.

Unlike many other electrochemical techniques, which are limited to the diffusion layer, bulk electrolysis (sometimes referred to just ‘electrolysis’) changes the composition of the bulk solution. Bulk electrolysis experiments aim to generate a quantitative conversion such that the amount of substrate consumed is directly proportional to the total consumed charge.

Spectroelectrochemistry (SEC) is an experimental technique that combines electrochemistry and spectroscopy. While electrochemical experiments provide information on macroscopic properties like reaction rates, spectroscopic techniques give information on a molecular level, such as the structure of molecules and their electronic configuration.

Ossila's photovoltaic substrates have been developed to maximise performance and fabrication efficiency for a range of modern photovoltaic device types where ITO series resistance becomes critical.

The schematics below show the layout of the substrates along with the available deposition shadow masks. The pixelated anode substrates come with six ITO fingers which define the pixels plus an additional cathode bus-bar.

The below diagram shows an exploded view of how the evaporation stack fits together. At the base of the system is the lower support which prevents the thin and flexible shadow masks from warping.

The exploded diagram below illustrates the layers typically used with the evaporation-free OFET substrates. The substrates contain pre-patterned ITO source-drain contacts onto which the semiconductor is deposited before a gate insulator is spun on top and finally the gate material finishes the device.

The Long Channel Organic Field-Effect Transistor (OFET) source/drain evaporation stack is designed to make fabrication as simple as possible so you can focus on material testing rather than fabrication.

Organic photovoltaic cells (OPVs) or organic light emitting diodes (OLEDs) can be easily manufactured using Ossila’s pre-patterned ITO substrates and a few simple spin coating and evaporating steps.

Viscoelastic transfer using polydimethylsiloxane (PDMS) stamps is one of the methods used for the deterministic placement of 2D materials and the fabrication of van der Waals heterostructures.

This video is a guide on how to make perovskite films when processed inside a nitrogen filled glove box. The resultant devices achieve efficiencies greater than 19% PCE.

This video provides a walk through guide on how to clean substrates for photovoltaic and OLED fabrication.

This video provides a guide to making efficient air-processed perovskite devices.

This video details the effects humidity has on air-processed perovskite films.

While a large part of research into the bulk heterojunction morphology of organic solar cells focuses on component choice,1 the morphology is also tuned by a host of processing conditions.

Of the significant efforts in research devoted to NFAs, the proposal of the fused-ring system ‘ITIC’ in 2015 has generated the most success.

Typically, polymer-based organic semiconductors (OSCs) are associated with OPVs. However, small molecules are also showing significant promise in terms of NFAs,2–4 and have similarly tunable properties (such as band-gap width).

Typically, organic photovoltaics (OPVs) are manufactured in the form of a bulk heterojunction (BHJ) cell, where the active layer consists of a blend of donor and acceptor materials with various interfacial layers and electrodes.

The majority of organic photovoltaics (OPVs) in research are based upon a binary active-layer mixture (of donor and acceptor materials) in the form of a bulk heterojunction (BHJ).

The new Ossila Potentiostat has been designed to help electrochemists perform cyclic voltammetry for less. The complete system includes cyclic voltammetry software, an electrochemical cell, and everything you need to start taking measurements.

Synthesising high quality quantum dots (QDs) can be a complex process. Two major routes to the synthesis have now been developed: room temperate synthesis and synthesis by hot injection.

>Over the last two decades, quantum dots have elicited a considerable amount of excitement and attention from both research scientists and the media. When Sony launched their XBR line of televisions in 2013, quantum dots successfully moved from pure research into the commercial sphere. Despite this, there are still some barriers to overcome before we can expect to see widespread adoption of quantum dot-based products.

Dr James Kingsley describes the engineering behind our vacuum-free spin coater, and demonstrates spinning with flexible substrates, silicon fragments and even parafilm.

Compact, versatile, vacuum free and low maintenance, our spin coater has become one of our bestselling pieces of equipment since its launch last year.

The Ossila Contact Angle Goniometer provides a fast, reliable, and easy method to measure the contact angle or surface tension of a droplet.

Ossila's Dip Coater is a system designed to deposit thin wet films through the controlled immersion and withdrawal of a substrate from a reservoir of solution.

The Ossila Four-Point Probe System is a low-cost solution for rapid and reliable measurement of the sheet resistance, resistivity and conductivity of materials.

Ossila's inert atmosphere Glove Box comes equipped with high accuracy oxygen and humidity sensors, quick purge function and antechamber for quick item transfer.

The Ossila LED Measurement System is a low-cost solution for reliable current-voltage-luminance and lifetime measurements of light emitting diodes.

Ossila's USB powered Optical Spectrometer has been designed to simplify the optical characterisation of thin films, solutions, nanocrystals and more.

Ossila’s Potentiostat is low-cost and easy-to-use system for performing cyclic voltammetry measurements. Cyclic voltammetry is one of the most widely used electrochemical techniques, providing important information about materials.

The Ossila Slot-Die Coater has been designed for simple operation and easy maintenance. An integrated high-precision Syringe Pump allows for accurate flow rates.

The Ossila Solar Cell I-V Test System is a low-cost solution for reliable current-voltage characterisation of photovoltaic devices.

The vacuum-free Ossila Spin Coater is compact and portable to optimise space in the glovebox and produce high-quality coatings without substrate warping.

Ossila's Syringe Pump has been designed to move volumes of fluids accurately and repeatedly at specified rates. User manual for single and dual models.

Ossila's Source Measure Unit (SMU) can measure a wide range of research devices including photovoltaics, LEDs and OLEDs, transistors, and more.

Ossila's UV Ozone Cleaner is designed to provide a simple, inexpensive, and efficient method of obtaining ultra-clean surfaces free of organic contaminants.

The latest software and drivers including our cyclic voltammetry software for the Ossila Potentiostat and more.