EXTRAORDINARY OPTICAL TRANSMISSION IN SOLAR CELLS

HERE WE PROPOSE THAT PROPERLY DESIGNED NANOWIRES AT THE INTERFACE BETWEEN TWO MATERIALS OF DIFFERING REFRACTIVE INDEX CREATE NEGLIGIBLE SHADOWING. MOST OPTOELECTRONIC DEVICES, SUCH AS SOLAR CELLS AND LIGHT EMITTING DIODES (LEDS), NEED ELECTRICAL CONTACTS ON THE TOP SURFACE OF THE DEVICE, BUT THESE CAUSE LIGHT REFLECTION AND ABSORPTION LOSSES. SO FAR THIS HAS BEEN VIEWED AS AN UNAVOIDABLE COMPROMISE LIMITING THE OVERALL ENERGY CONVERSION EFFICIENCY OF OPTOELECTRONIC DEVICES. INSTEAD WE PROPOSE THAT METALS CAN BE MADE, FOR MANY PRACTICAL PURPOSES, FULLY TRANSPARENT. OUR PRELIMINARY RESULTS SUGGEST THAT IT IS POSSIBLE TO HAVE ZERO, AND EVEN NEGATIVE EFFECTIVE SHADOW FACTORS, AND WE PROPOSE TO EXPERIMENTALLY DEMONSTRATE NANOSTRUCTURED TOP CONTACTS WITH NEAR ZERO SHADOW FACTORS IN A BROADBAND WAVELENGTH RANGE. THIS PROPOSAL MIGHT ENABLE A NEW GENERATION OF HIGHLY EFFICIENT SOLAR CELLS AND LIGHT EMITTING DIODES.