Gas Mixer for Thin Film Solar Cells Development

Gas blending applications for thin film solar cells development.

Over the last 30 years, the industry has made great strides in the development of sources for sustainable energies (also known as green energies). After the success of anti-global warming awareness campaigns undertaken by all countries, switching to green energy production has become a must.

Significant optimization of sustainable production techniques, in order to obtain necessary and satisfying results, has become a priority. Among all modern techniques of sustainable energy production, sunlight-based technology is one of the most developed and promising applications.

This technology makes use of solid-state devices, called solar cells, which are capable to generate electricity directly from sunlight via the photovoltaic effect. Optimization of sunlight technology aims now to increase solar cells’ efficiency and lower the production costs of these devices.

Solar Cells Development.

Silicon is, and it has been, the more used and one of the more suitable materials for solar cell manufacturing processes. Apart from its chemical and physical properties (which makes it adequate for sunlight adsorption purposes), silicon has been chosen for its great industrial availability.

In the early stages of solar cell development, silicon was obtained from the huge amount of crystalline silicon (c-Si) wafers discarded by microprocessor manufacturing industries. Those types of wafers were made of monocrystalline silicon (an efficient but expensive material), soon replaced by polycrystalline silicon (less efficient but considerably cheaper). Just recently a new technology based on the use of amorphous silicon (a-Si), produced with common CVD techniques, has emerged.

Usually, we refer to solar cells based on the p-n junction principle as the first-generation photovoltaic cells. The advent of a-Si thin films has allowed undertaking the development of two new solar cell generations.

Second-generation cells are still based on the p-n junction principle but are produced by replacing the common thick c-Si with an amorphous silicon thin layer. The main advantage of these devices isn’t the efficiency (a-Si solar cells have lower energy conversion efficiency compared with c-Si ones) but the cost. Silicon’s cost is by far the largest production factor in solar cell manufacturing and a-Si cell production requires approximately 1% of the silicon needed for typical c-Si cells. Now the new target of the research is the development of third-generation cells.

Third-generation cells are multi-layer structure devices, composed of a combination of a-Si and c-Si (or other ceramic materials) thin layers. Unlike first and second-generation cells, this kind of photovoltaic device is based on a multi-junction principle. This new approach makes them more efficient in converting sunlight into electricity but also requires a more complex and more expensive production process.

Thin film technology.

The great interest in third-generation cells derives from the unique features of these devices. Due to their extreme thinness, these new-generation solar cells are flexible materials with lightweight physical characteristics that make them suitable for many applications.

The most important example of this new technology’s usefulness is the thin film solar panels. Thin film panels are particularly suitable for building installation (usually roofs or other dedicated surfaces) and at the same time, they present more advantages than common industrial panels made by first-generation solar cells. Aside from their low weight, thin film solar panels are relatively easy to install, can be walked on, and aren’t subjected to wind lifting.

Production – Chemical Vapor Deposition.

Both second and third-generation photovoltaic solar cells share the same production process based on chemical vapor deposition (CVD) techniques. CVD allows the production of devices with a thickness range that varies from a few nanometers to tens of micrometers. Since the development of thin solar cells is still in its early stages, the most suitable deposition method and process conditions choice is currently widely debated topics.

The major deposition techniques are plasma-enhanced CVD (PECVD) and hot-wire CVD (HWCVD), with a slight preference for the latter. Deposition outcomes related to process parameters are well studied. Temperature, chamber pressure, and substrate material have shown their strong dependence on the thin solar cells produced until now, but obviously, particular attention has also been paid to the working gas mixture.

The commonly used gas mixtures are composed of hydrogen (as an activator gas) and a silicon-source gas (usually silane). The relative amount of components in the gas mixture and especially the effect of dynamic mixture changes on the deposition results are crucial parameters of great interest and in order to study them, a suitable instrument is definitely needed.

The MCQ Instruments solution.

The MCQ Instruments suggests the use of its Gas Blender Series, as the ideal professional series of Gas Mixers for precision gas mixtures preparations, gas flow meter control, and dynamic gas mixtures applications. The Gas Blender Series is designed to work with up to 6 components of non-aggressive gas mixtures. The instruments will be calibrated on customer request and in case of need it’s possible to work with different gas settings configurations through the use of conversion factors related to each gas media.

The Gas Blender Series’ high precision (1% accuracy for each channel), high repeatability (0,16% of reading value), and fast response time for setpoint value changes make it suitable for gas mixtures’ fine blending. Bundled with the instruments, MCQ provides the Gas Mixture Creator Software, a SOFTWARE (compatible with any Windows-operating desktop and laptop personal computer, or touch screen for the latest products) that ensures an easy and intuitive way to manage mixtures dynamically with full automation.

Choose your Gas Mixer.

Easy to Use, automated, flexible, multi-gas types. Start creating your dynamic Gas Mixtures by just using pure gases.

GB100

Total Flow Rate: Up to 1,5 L/min

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