Without moving parts, electricity can be generated directly from light and sometimes from infrared radiation as well. This is achieved by using materials that exhibit photogeneration of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity. This conversion is called the photovoltaic effect, and the field of research and development related to solar cells is known as photovoltaics.
There are many photovoltaic technologies. The market is rigged by government subsidies in many countries, so sales, particularly in the USA, Germany and Japan, are much higher than they would be in free markets and they mostly involve heavy, brittle, silicon constructions. This is not necessarily helpful to newer, more viable options because sites and purchasing budgets can be taken by the old uneconomic silicon product and therefore not be available for the new ones. However, in many countries there are also subsidies to support new developments.
Button, otherwise known as coin batteries are now extremely popular. They are even seen in talking gift cards and many disposable toys and promotions. However, they use substantial amounts of lithium or silver and they usually have unreliable spring contacts that add yet more expense and bulk.
Certainly applications such as active RFID have seen button batteries take over almost entirely from larger batteries in recent years and the next stage will be for a substantial number of these button batteries to be replaced with laminar batteries and the market expanded by active tags being made with laminar batteries that were impossible before because of thickness or lack of flexibility.
How to learn more
IDTechEx has now provided the newly researched report Introduction to Printed Electronics to address this. We include similar devices that are not yet printed, but are likely to be printed in future, so readers do not miss the big picture.
165 tables and figures, in this 200 page report, distil the information, highlighting where, why and what next. There is a critical look at the many options and projects with a frank assessment of which have a great future and which do not. The report is designed to be easily read; it is free of equations and academic references but it contains much of interest to those with a basic knowledge of chemistry, physics and electronics. The emphasis is on commercialisation, timescales and the many totally new products that will result, with the activities and strategies of over 100 companies compared and contrasted. Quantum dots, wallpaper lighting, origami electronics, smart packaging, electronic skin patches, nanolasers - it is all here. The main sections address the needs, from smart airports to medicine, substrates, the printing technology, printed semiconductors, transistors, memory, seven types of display, four types of lighting and many forms of photovoltaics, battery, fuel cell and sensor that are or will be printed. Many timelines for the future are provided. No other report on the subject is as comprehensive and timely. For more details click here.