Since the invention of electricity, people (science people) have always been preoccupied about how to make their devices smaller and smaller. Now, at the end of the first decade of the 21st century, people have reached the theoretical miniaturization of their machines, but are lacking a source of power for them, one small enough to fit into the description of “nano-scale batteries”.
The green energy movement has brought, like wars brought technological advances, a wave of alternatively-powered inventions, among which it is the most recent miniature solar cell, designed to power microscopic machines.
A team of researchers led by Xiaomei Jiang from the University of South Florida, did some research and built solar cells made of an organic polymer. In their experiments, they joined 20 of these tiny cells. So how tiny are they? Well, these solar cells are about the size of a size 12 “o” font (lowercase).
They want to use the solar cells to power tiny devices able to detect chemical leaks.
Jiang and her colleagues fabricated their array of 20 tiny solar cells as a power source for running a microscopic sensor for detecting dangerous chemicals and toxins. The detector, known as a Micro-Eletro-Mechanical system (MEMS) device, is built with carbon nanotubes and has already been tested using ordinary DC power supplied by batteries. When fully powered and hooked into a circuit, the carbon nanotubes can sensitively detect particular chemicals by measuring the electrical changes that occur when chemicals enter the tubes. The type of chemical can be distinguished by the exact change in the electrical signal.
The device needs a 15-volt power source to work, so far and Jiang’s solar cell array can provide about half of that – up to 7.8 volts in their preliminary lab tests. The next step is to optimize the device to increase the voltage and then combine the miniature solar array to the carbon nanotube chemical sensors. Jiang estimates they will be able to demonstrate this level of power with their next generation solar array by the end of the year.
These innovations in miniature solar cells are positive to the energy industry if developed more, because the need for miniaturization has always brought the need for efficiency. You can’t have one without the other.
Note: the picture with the solar car is not related to this discovery, it’s something I liked to represent this article.