Tomorrow’s Tech, Today: A Glimpse of the Incredible World of Transparent Electronics

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Safety today, has become an extremely important issue. It sounds funny given the fact that safety is one thing that should always be prioritised. But, a few years ago, that was not really the case. From our automobiles to consumer electronics, our everyday drivers were a little less safe. Today, however, things are a bit different. Safety has taken centre stage. In automobiles, in our cars, one technology in particular has made driving extremely secure: heads up display. It is the technology of showing the driver important details of the dashboard, like the speed, indicators, and fuel economy, directly on the windshield.

If you’re any bit inquisitive, you would surely wonder as to how an electronic display can be incorporated on a transparent film. It is intriguing, because you don’t get to see the connecting wires and the electronic components. And it makes you wonder one thing: how on earth is there a circuit when there doesn’t seem to one? Welcome to the world of transparent electronics. Still in its nascent stage, transparent electronics employs wide band-gap semiconductors for making circuits that are invisible to the human eye. So, the heads up display in your car is made possible only because of transparent electronics. However, when you doddle a bit more, you’ll know that the heads up display is just the tip of a technological iceberg. What we’re dealing with here is something way beyond that. We’re talking of an electronic circuit technology that will change the world of electronics forever.

Transparent electronics is an emerging science and technology field focused on producing invisible electronic circuitry and opto-electronic devices. Applications include consumer electronics, new energy sources, and transportation. For example, automobile windshields could transmit visual information to the driver. Glass in almost any setting could also double as an electronic device, possibly improving security systems or offering transparent displays. In a similar vein, windows could be used to produce electrical power. Other civilian and military applications in this research field include real time wearable displays.

By now, it is clear that transparent electronics is a big concept. At the same time, it is extremely complex. Its functioning can be quite a handful to understand. The two technologies which preceded and underlie transparent electronics are Transparent Conductive Oxides(TCOs) and Thin- Film Transistors (TFTs). TCOs constitute an unusual class of materials possessing two physical properties- high optical transparency and high electrical conductivity. They are generally considered to be mutually exclusive. This peculiar combination of physical properties is only achievable if a material has a sufficiently large energy band gap so that it is non-absorbing or transparent or transparent to visible light, and also possesses a high enough concentration with a sufficiently large mobilitythat the material can be considered to be a good conductor of electricity.

The three most common TCOs are indium oxide, tin oxide, and zinc oxide. All these materials have band gaps above that required for transparency across the full visible spectrum. Thin-Film Transistors are another technology underlying transparent electronics, since it is a bridge between passive electrical and active electronic applications. Although TFTs were the subject of the earliest transistor patents, the first realisation of a TFT was reported in 1961 by Weimer and fabricated via vacuum evaporation using CdS as a channel layer. None of these undertakings involved an attempt to realize a fully transparent TFT.

You have a heads up display in your car because of the simple fact that it is an expensive one. It is a technology that is found only in some of the high-end luxury cars. That means, it isn’t a cheap technology. It isn’t cheap because of the very principles of Physics that it has follow. The amalgamation of the opto and electro capabilities of a device is extremely hard to achieve. The challenge is that the transistor materials must be transparent to visible light yet have good carrier mobility. This requires a special class of materials having contra-indicated properties because from the band structure point of view, the combination of transparency and conductivity is contradictory.

Oxides Play A Key Role

One major reason why there has been such interest and activity in transparent electronics recently is that there has been a sharp jump in the carrier mobility of transparent semiconductors, which determines transparent TFT characteristics. This now exceeds the carrier mobility of materials such as low temperature poly-Si (LTPS) and amorphous Si used in LCD panels. While there are remaining problems, transparent oxide p-type semiconductors have also been in development. Even better, it means lower cost. Transparent semiconductors such as GaN and diamond are already known, but they come at high cost which makes them impossible to use in transparent electronic devices demanding relatively large screens, such as displays. The candidate materials attracting the most interest can be broadly divided into two oxide categories. The first group is zinc oxide, and the second is amorphous oxides with heavy metal content, such as amorphous.

Advancements Made In Transparent Electronics

Significant advances in the emerging science of transparent electronics, creating transparent “p-type” semiconductors that have more than 200 times the conductivity of the best materials available for that purpose a few years ago. This basic research is opening the door to new types of electronic circuits that, when deposited onto glass, are literally invisible. The studies are so cutting edge that the products which could emerge from them haven’t yet been invented, although they may find applications in everything from flat-panel displays to automobiles or invisible circuits on visors. Most materials used to conduct electricity are opaque, but some invisible conductors of electricity are already in fairly common use.

Market Of Transparent Electronics

Eventually the materials suite used by transparent electronics will stabilize and the role of organic electronics materials and nanomaterials in transparent electronics will become clearer. But as we have explained above, the possible technical directions that these materials are likely to take are fairly well defined; although we should not exclude surprises entirely. Forecast of Transparent Electronics Products by Application Opportunities in the area of the transparent electronics products themselves can be somewhat difficult to pick out. This is not just because of the diversity of the possible products that can be built within the context of transparent electronics paradigm, but also because both the actual past of transparent electronics so far and the somewhat futuristic prognostications about transparent electronics that have been widely published are a distraction from understanding what can really be achieved in the next few years with transparent electronics: Too cool to succeed.

Transparent electronics suffer from the fact that it is so cool that it virtually cries out to be built into highly futuristic scenarios. And this is exactly what has happened. Just a casual look at the literature on transparent electronics—even the formal technical literature—usually reveals quite quickly a slew of references to science fiction movies in which transparent electronics are featured. The favourite in this regard is the Tom Cruise movie ―Minority Report. This is all a lot of fun, but gives a false impression of the current state of the art in transparent electronics and what might be achieved using this technology. Watching Cruise in ―Minority Report, it is never quite clear just why he is using transparent displays in his work. In other words, these display are props not just in the sense that they are not physically real (they don‘t actually function). They are also divorced from market realities.

Can The Market of Transparent Electronics Grow Big?

Today, the market and the market sentiment towards transparent electronics seems highly limited. People are intimidated by its complexity. They’re also sceptical of the technology’s profitability. Experts say that while the market for transparent electronics will surely grow in the next two or three decades, there are several things that need to be addressed for it to happen. Manufacturers have to keep in mind of the aesthetics of the products. Apart from being functional, any product should be easy to use and at the same time should have a visual appeal. That is, for transparent electronics, the jump has to be made from sci-fi movies to the realms of the definitive world. Then, there is the important aspect of integration. Everything around us cannot be made transparent because that would render our world somewhat bland.

So, transparent circuitry should be able to integrate itself amid the sea of electronic circuits already in use today. Until that happens, people will always be wary of investing their time and money in the technology. And perhaps the biggest thing that needs to be addressed is of profitability. The technology of transparent electronics is extremely costly to manufacture. That means, by the time it is mass produced, the costs will add up even more. And we all know that people will always be hesitant of paying that kind of money. In short, for the market of transparent electronics to grow, it has to address the areas of aesthetics, integration, and economics.

What Does The Future Behold?

It should be apparent from the discussion that although much progress has been made in developing new materials and devices for high performance transparent solar cells, there is still plenty of opportunity to study and improve device performance and fabrication techniques compared with the non-transparent solar cell devices. In particular, the stability of transparency solar cells has not been studied yet. Solution-processable transparent PSCs have become a promising emerging technology for tandem solar cell application to increase energy conversion efficiency. The transparency of solar cells at a specific light band will also lead to new applications such as solar windows. The field of energy harvesting is gaining momentum by the increases in gasoline price and environment pollution caused by traditional techniques.

Continued breakthroughs in materials and device performance, accelerate and establish industrial applications. It is likely that new scientific discoveries and technological advances will continue to cross fertilise each other for the foreseeable future. Graphene is transparent and can be used as a potential material. It would not be a complete surprise to find players in the smart window; sensor and lighting industries also begin to invest substantially in transparent electronics over the next few years.

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