Article last updated on: Sep 04, 2018

What is a solar panel?

Solar panel electricity systems, also known as solar photovoltaics (PV), capture the sun’s energy (photons) and convert it into electricity. PV cells are made from layers of semiconducting material, and produce an electric field across the layers when exposed to sunlight. When light reaches the cell, some of it is absorbed into the semiconducting material and causes electrons to break loose and flow. This flow of electrons is an electric current, that can be drawn out and used for powering outside devices. This current, along with the cell’s voltage (a result of built-in electric fields), define the power that the solar cell is capable of producing. It is worth mentioning that a PV cell can produce electricity without direct sunlight, but more sunshine equals more electricity.

Solar panel array photo

A module, or panel, is a group of cells connected electrically and packaged together. several panels can also form an array, which can provide more electricity and be used for powering larger instruments and devices.

Different kinds of Solar cells

Solar cells are roughly divided into three categories: Monocrystalline, Polycrystalline and Thin Film. Most of the world’s PVs are based on a variation of silicon. The purity of the silicon, or the more perfectly aligned silicon molecules are, affects how good it will be at converting solar energy. Monocrystalline solar cells (Mono-Si, or single-crystal-Si) go through a process of cutting cylindrical ingots to make silicon wafers, which gives the panels their characteristic look. They have external even coloring that suggests high-purity silicon, thus having the highest efficiency rates (typically 15-20%). They are also space efficient (their efficiency allows them to be small) and live longer than other kinds of solar panels. Alas, they are more expensive than other kinds and tend to be damaged by external dirt or snow.

Polycrystalline silicon (p-Si or mc-Si) solar cells do not go through the abovementioned process, and so are simpler and cost less than Monocrystalline ones. Their typical efficiency is 13-16%, due to lower silicon purity. They are also bigger and take up more space.

Thin-Film solar cells (TFSC), are made by depositing one or several thin layers of photovoltaic material onto a substrate. Different types of TFSCs are categorized by which photovoltaic material is deposited onto the substrate: Amorphous silicon (a-Si), cadmium telluride (CdTe), copper indium gallium selenide (CIS/CIGS), polymer solar panels and organic photovoltaic cells (OPC). Thin-film modules have reached efficiencies of 7-13%. Their mass production is simple, they can be made flexible and are potentially cheaper to manufacture than crystalline-based solar cells. They do, however, take up a lot of space (hampering their use in residential applications) and tend to degrade faster than crystalline solar panels.



Solar power advantages and disadvantages

Solar power is free and infinite, and solar energy use indeed has major advantages. It is an eco-friendly, sustainable way of energy production. Solar energy systems today are also much cheaper than they were 20 years ago, and save money in electricity expenses. In addition, it is a much environmentally cleaner form of energy production that helps reduce global warming and coal pollution. It does not waste water like coal and nuclear power plants and is also considered to be a form of energy that is much safer for use.

Although solar power production is widely considered to be a positive thing, some downsides require mentioning. The initial cost of purchasing and installing solar panels can be substantial, despite widespread government subsidy programs and tax initiatives. Sun exposure is critical and so location plays a significant role in the generation of electricity. Areas that are cloudy or foggy for long periods of time will produce much less electricity. Other commonly argues disadvantages regard insufficiency of produced electricity and reliability issues.

Solar power applications

Common solar energy applications include various residential uses such as solar lighting, heating and ventilation systems. Many small appliances utilize solar energy for operation, like calculators, scales, toys and more. Agriculture and horticulture also employ solar energy for the operation of different aids like water pumps and crop drying machines. The field of transportation has been interested in solar powered vehicles for many years, including cars, planes and boats that are vigorously researched and developed. Solar energy also has various industrial applications, ranging from powering remote locations as well as space and satellite systems, to powering transportation signals, lighthouses, offshore navigation systems and many more.

Solar technologies are vigorously researched, aiming to lower costs and improve existing products as well as integrate PV systems in innovative products like PV-powered curtains, clothes and laptop cases.

Graphene and solar panels

Graphene is made of a single layer of carbon atoms that are bonded together in a repeating pattern of hexagons. It is a 2 dimensional material with amazing characteristics, which grant it the title “wonder material”. It is extremely strong and almost entirely transparent and also astonishingly conductive and flexible. Graphene is made of carbon, which is abundant, and can be a relatively inexpensive material. Graphene has a seemingly endless potential for improving existing products as well as inspiring new ones.

Solar cells require materials that are conductive and allow light to get through, thus benefiting from graphene's superb conductivity and transparency. Graphene is indeed a great conductor, but it is not very good at collecting the electrical current produced inside the solar cell. Hence, researchers are looking for appropriate ways to modify graphene for this purpose. Graphene Oxide (GO), for example, is less conductive but more transparent and a better charge collector which can be useful for solar panels.

The conductive Indium Tin Oxide (ITO) is used with a non-conductive glass layer as the transparent electrodes in most organic solar panels to achieve these goals, but ITO is rare, brittle and makes solar panels expensive. Many researches focus on graphene as a replacement for ITO in transparent electrodes of OPVs. Others search for ways of utilizing graphene in improving overall performance of photovoltaic devices, mainly OPVs, as well as in electrodes, active layers, interfacial layers and electron acceptors.

Commercialization efforts

While graphene-based solar cells are not currently commercially available, some efforts are bearing fruit in regards to the use of graphene in auxiliary aspects of PV. One such example is ZNShine Solar's G12 evolution era series - comprised of a 12-busbar graphene module, 5-busbar graphene module and double-glass graphene module. According to reports, the application of ZS's graphene film layer increases light transmission performance of the glass itself. In addition, Znshine Solar's modules are self-cleaning. In July 2018, ZNShine Solar won the bid to provide 37.5MW of PV modules to Bharat Heavy Electricals Limited (BHEL), India's largest power generation equipment manufacturer. According to the contract, 10% of the shipment will be graphene-coated solar panels.

Further reading

Latest Graphene Solar Panels news

A new guide to promising perovskite materials: The Perovskite Handbook

The Graphene-Info team takes pleasure in recommending our new book - The Perovskite Handbook. While not focused on graphene, we believe that any person interested in advanced materials and emerging technologies would find that perovskite materials are an area of focus that should not be ignored.

The Perovskite Handbook

This book gives a comprehensive introduction to perovskite materials, applications and industry. Perovskites offer a myriad of exciting properties and are considered the future of solar cells, displays, sensors, lasers and more. The promising perovskite industry is currently at a tipping point and on the verge of mass adoption and commercialization.

The graphene industry should especially pay attention to perovskites as much work is done on combining these two material technologies to create better solar cells, displays and more.

MIT to receive $1,500,000 in funding from the DOE for graphene-enabled solar applications development

MIT recently received $1,500,000 in funding from the U.S. Department of Energy for its project titled "Low-Cost, High-Efficiency III-V Photovoltaics Enabled By Remote Epitaxy through Graphene"

This funding was a part of the Solar Energy Technologies Office Fiscal Year 2018 (SETO FY2018) funding program, which addresses the affordability, flexibility, and performance of solar technologies. The total funding was $53 million for 53 projects.

Graphene Investment Guide

The Graphene Flagship moves towards new stage

The Graphene Flagship was launched in 2013 with the mission to take graphene and related layered materials from academic laboratories to the market, revolutionize multiple industries and create economic growth and new jobs in Europe. Five years later, the Flagship consortium has reported that it successfully completed the Core1 phase and is progressing towards more applied phases. It is reportedly on its way to achieving its objective of developing the high potential of graphene and related 2D materials to the point of having a dramatic impact on multiple industries.

The Reviewing Panel thoroughly examined the results obtained in this Core1 phase and concluded that for many topics, there has been a clear transformation of the activities, moving from individual research projects to genuine collaboration towards larger goals – exactly what a Flagship project should aim for. Nearly all milestones and key performance indicators have been met, often exceeding expectations. There are numerous examples of significant scientific and/or technological achievements, with clear progress beyond the state of the art. The Work package on Photonics and Optoelectronics led by ICREA Prof. at ICFO Frank Koppens was recognized as one of the closest to being brought into industrial exploitation due to its significant potential for both scientific breakthrough and innovation.

Verditek secures funds to back graphene JV with Paragraf

Verditek, a clean technology company, is raising GBP2 million (USD $2.57 million), pre-expenses, for its new solar factory in Italy and a graphene project. The London-based cleantech company said that a UK institutional investor and a European-based family office took part in the placing, without revealing their names.

The funding will support the ramp up of the solar factory in Lainate, Italy and its working capital requirement. At the plant the company will make light-weight solar panels. In addition, Verditek said the proceeds give it additional financial flexibility to pursue the “very promising work” with Cambridge-based technology firm Paragraf as part of their graphene joint venture. The partners said in December 2017 they would work to develop graphene-based solar cells and modules.

Researchers develop graphene-enhanced biophotovoltaic technology

Researchers at UC Riverside are attempting to integrate biological components with photovoltaic cells to deliver fully sustainable solar energy. The team's biophotovoltaic device is built from renewable carbon by integrating graphene hybrids and the phototropic protein bacteriorhodopsin.

UCR team creates graphene-enhanced biophotovoltaic technology image

Existing photovoltaic technology is not fully capable of realizing the promise of sustainable solar energy. Commercial and emerging photovoltaic technologies require energy-intensive extracting and manufacturing processes and often require metals like tin that generate social conflict and environmental harm.

XFNANO: Graphene and graphene-like materials since 2009 XFNANO: Graphene and graphene-like materials since 2009