Solar panel "efficiency" comes in several forms: * efficient use of space * efficient use of capital * efficient conversion of received energy etc. Except in the most intensive versions of solar farms, space efficiency isn't as important as capital cost & flexibility. Thus, if one could "paint" a 10% efficient coating cheaply onto an available surface, that would be far better than a 25% efficient solar array that required new construction to support the panel array. For rooftop use, weight & aesthetic issues may dominate efficiency. For example, if I could get good looking roof tiles that also functioned as solar collectors, that would be a big win, because I could cover 100% of my roof instead of only a small %. However, I've been told that nearly every reasonably efficient solar surface will end up looking *black*. So we need to find artists & architects who can make black roofs look good. BTW, the same "quantum dot" techniques used to improve solar cell efficiency can also be used to selectively *reflect* long infrared (aka "heat") while *absorbing & converting* shorter wavelengths, thus reducing the load on the air conditioning system & reducing the need for the electricity to run that A/C system. Here in California, I've noticed that farmers have been replacing *crop rows* with *solar panel rows*. This trend will continue, since solar panels don't have to be watered in order to produce profits! At 12:53 PM 5/19/2016, Warren D Smith wrote:

As far as I know some green plants and algae do have several kinds of chlorophyll-containing macro-molecular assembly, each tailored to different region of spectrum, but no single life form employs a continuum. (If this was such a great idea, then why not?) Perhaps however a community of 1000 algal species layered at different depths in water could be argued to form such a continuum (not a realistic model of nature). And also, far as I know, the overall efficiency of green plants at converting to sunlight to biomass=fuel is way worse than that 35% efficient solar cell. What if the plants were living in a massively-CO2-rich atmosphere? Would they be efficient then?