Thank you for your response and question Dr. Ruktanonchai! The transparent solar cell display will not be as effective indoors compared to outdoors. In order for our solar concentrator to be transparent, it must first allow the majority of visible light to pass through. Our solar panel then uses redirected infrared and ultraviolet light to generate electricity. Some sources of indoor lighting, particularly halogen lamps incandescent lamps, can emit a varied amount of ultraviolet energy providing some charge to the device. In fact 70% of energy emitted by incandescent lamps consist of infrared energy. Common fluorescent lamps used today can still transfer ultraviolet energy with variable strengths depending on the proximity to the lamp. While the charge provided indoors will not be nearly as powerful as direct sunlight, some electric charge can be generated from indoor lamps and light leaking in through windows. It would be suggested that the devices be kept near windows or light sources while being indoors for maximum charging capacity. When outdoors these concentrators can charge 5 milliWatt-hours per square centimeter. Across the entire screen these concentrators can generate 250-300 milliWatt-hours total, roughly 10 to 20 percent of an iPhone battery.
Best regards,
The Photoelectrics

Thank you for your feedback and questions Mr. Stavisky! The primary costs in the charging screen comes from only the tiny salts in the thin plastic screen and the regular photovoltaic cells surrounding the screen frame. Due to the small size and how thin our attachment is, the prices are minimal compared to common opaque panels, whose main price factor comes from the size and bulkiness of the product. Similar but less transparent solar cells of the same size compared to ours currently go for $2.30, so an estimate of $3 to $4 should be reasonable for this developing technology. For the price of a cup of coffee this attachment is economically feasible yet can provide continuous charge and electricity for a mobile device. Insulation can cost upwards of $20 per roll making them extremely expensive to cover large surfaces. While our attachment can not save as much electricity as a fully insulated house can, the price of implementation of our solar screen is considerably lower and when applied can still provide plentiful amounts of clean energy to power devices and reduce electricity usage. The advantage of this technology is the mobility and the fact that it can be used on the devices that are so common and crucial to so many in society today. Our devices are with us practically every day. Instead simply letting them sit there, it would be much more useful to contribute to the bigger cause by allowing them to harvest energy at a low cost. As the technology advances, we can further apply this to glass surfaces nearly everywhere – such as car windows, public displays, or windows of homes and skyscrapers. A typical skyscraper would have thousands of windows, and those that are almost fully covered in glass panes can reach more than ten thousand windows, such as the John Hancock Building in Boston. All this vertical space can be fully utilized in the future to harvest solar energy with this technology we have presented. As an added plus, the use of these solar panels would substantially reduce costs of cooling buildings, as the infrared energy is absorbed by the panels. Overall, transparent solar cells have the potential to be cost-efficient as well as energy saving.
Best regards,
The Photoelectrics

Thank you for your response and questions Mr. Drayton! As this technology is newly emerging, it is currently present primarily in university laboratories with graduate researchers working on them to improve efficiency. Although the PV materials used are available to labs and the industry, no product has been officially released and we currently do not have the technology and skill to build this solar cell by ourselves. As of now, we have not tried a prototype of this technology but would love to experiment with it if we can. Our biggest barriers and challenges consist of maximizing efficiency of these cells up to a point in which hopefully users can rely solely on these solar concentrators to recharge their mobile devices. These advancements however are slow and may take many years to come to achieve. In order to motivate people to use this device, we plan on combining the popularity and durability of screen protectors with the energy regeneration capabilities of these solar concentrators. Integrating these low cost transparent solar concentrators with screen protectors and phone cases would not only motivate buyers but add another functionality to these common protectors. This however is possible without hindering functionality of the touch screen display as current screen protectors go from thicknesses of a thin film to 0.1 inches thick without hindering performance, and the solar cell currently being able to reach thicknesses of 0.05 cm without losing functionality.
Best regards,
The Photoelectrics

Thank you for your response and questions Ms. Skog! Conventional solar cells we see today range averagely from 11% efficiency to 15% efficiency. Many solar cells are listed at higher efficiencies, but those technologies have not undergone mass production and are not available to the public due to the material and processes used. The technology we propose here is still under development as well and could be further modified to increase efficiency, and this depends on the PV material used. In order to create a transparent solar cell, the material will typically be polymers, including conductive organic polymers like the salts included in our paper. Other choices range from silver nanowires with titanium dioxide, biomimetic dyes, and more. The organic or partially organic nature of these polymers allow scientists to experiment and alter their properties in order to absorb specific wavelengths. In terms of versatility and ease of production, these materials definitely have advantages over silicon based solar cells. Regarding efficiency, time and development is still needed, but projections of organic materials aim for efficiencies above 15%. The amount of energy produced by a transparent solar cell applied to a smartphone would be about 5 milliWatt-hours per square centimeter, and if the cell covered the entire screen, this would mean about 250 to 300 milliWatt-hours. Current technology only enables a phone’s battery life to be extended by 10 to 20 percent, and is not efficient to sustain the entire charge of a phone’s battery. Due to the small area of a phone screen, a complete charge through this technology will be difficult to achieve. As for the touchscreen function coexisting with the transparent solar cell, this will not be a problem. The entire system, if not integrated with screen protectors, would have a thin (about 0.3 mm) of glass as a protection for the PV material. This would prevent damage in the solar cell or reduction in efficiency while the touchscreen is in use.
Best regards,
The Photoelectrics

Hi Matthew! Thanks for your questions! The production of these transparent solar cells is low cost with a high environmental impact when a large amount of people use these. Similar but semi-transparent solar cells of the same size compared to ours currently go for $2.30, so an estimate of $3 to $4 would be reasonable for this developing technology. With partial exposure to sunlight these can recharge between 250-300 mAh of electricity, roughly 10 to 20 percent of an iPhone’s battery capacity. With even a small percentage of all smartphone users using this attachment, the environmental benefits can be overwhelming.
As for your second question, the solar cell will not affect the usability of a mobile device. We often and commonly utilize screen protectors for the touch screens on these devices, and these protectors range from films to ballistic glass layers. The thicker ones on the market are about 0.1 inches thick, which would be 0.254 cm. One of our group members currently uses one of these, and the touchscreen works just as it would without one. Researchers current have been able to make the solar cell 0.05 cm thick or even less, so this would not be a problem for the response of the screen to touch.

Best regards,
The Photoelectrics

Hi Callie! Thanks for your comments and questions! The primary costs in our attachment consist only from the tiny salts in the thin plastic screen and the regular photovoltaic cells bordering the screen. This would be directly attached onto mobile devices, which do not need to be altered to be able to apply this technology. Our attachment for mobile devices are only as big as the display itself and are very thin, so overall costs will be very small per production unit. Similar but less transparent solar cells of the same size compared to ours currently go for $2.30, so an estimate of $3 to $4 would be reasonable for this developing technology. For the price of a cup of coffee this attachment is economically feasible yet can provide continuous charge and electricity for a mobile device. One way to further appeal this product to a larger audience would be the integration of these transparent solar charging attachments with phone cases and screen protectors. Screen protectors are commonly used to protect our glass displays from scratches and cracks. If we were to integrate solar charging capability with the strength of the screen protector, our product can serve two purposes while helping the environment. This however is possible without hindering the usage of the touch screen as current screen protectors can go from thin films to 0.1 inches thick ballistic glass without hindering usage. Combining screen protectors with these chargers will not only help save total costs, but motivate people to use these more.

Best regards,
The Photoelectrics