The Economist wrote an article on 23 Jul 2009 about 2 novel approaches to making electricity from sunlight by 2 solar companies in Israel.

GreenSun Energy, which is led by Dr Renata Reisfeld, thinks the way is to use less silicon. Traditional solar cells are made of thin sheets of the element covered by glass plates. In GreenSun’s cells, though, only the outer edges of the glass plates are covered by silicon, in the form of thin strips. The trick is to get the light falling on the glass to diffuse sideways to the edges, so that the silicon can turn it into electricity. Dr Reisfeld’s team do this by coating the glass with a combination of dyes and sprinkling it with nanoparticles of a metal whose nature they are not yet willing to disclose.

Amnon Leikovich, the firm’s boss, said the upshot is a device that could already, if put into production, deliver electricity at only twice the cost of the stuff that comes out of a conventional power station. That may not sound great, but the power from traditional cells is about 5 times as costly as grid electricity, so GreenSun’s system sounds like a winner for places that are not yet connected. Moreover, Mr Leikovich hopes that costs can be brought down, and efficiency improved, to achieve the alternative-energy nirvana of “grid parity”.

Jonathan Goldstein of 3GSolar hopes to get rid of silicon altogether. 3G’s “dye-sensitised” solar cells use titanium dioxide (more familiar as a pigment used in white paints) and complicated dye molecules that contain a metal called ruthenium. When one of the dye molecules is hit by light of sufficient energy, an electron is knocked out of it and absorbed by the titanium dioxide, before being passed out of the cell to do useful work.

This is a well-known process (it was invented 20 years ago by Michael Grätzel, a physicist at the Federal Polytechnic School in Lausanne, Switzerland) and several firms are trying to commercialise it. Dr Goldstein, however, thinks 3G has an edge over its rivals because of the way it draws off the power—though he is reluctant to go into details. One thing that is clear, though, is that dye-sensitised cells will be cheap to make. Both silicon cells and a third technology, so-called thin-film cells (which use novel materials such as cadmium telluride deposited onto sheets of glass or steel), have to be made in a vacuum. That is expensive. Dye-sensitised cells can be made by a process similar to screen printing, which is cheap. Dye-sensitised cells are not as efficient as silicon ones, but their cheapness may outweigh that in many applications.

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Further research on GreenSun Energy led to this website which lists solar startups with funding info and short description. There are hundreds of private companies on the list(!) and some only had angel funding and no VC funding yet. Note that the US-based company GreenSun Energy in this list is not the same as the Israeli company (website: www.greensun.biz) mentioned above.
Solar Startups, Part 1: c-Si, Installers, Financiers, BoS, Misc
Solar Startups, Part 2: CPV
Solar Startups, Part 3: Next-Gen PV
Solar Startups, Part 4: Thin Film

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3GSolar (aka Orion Solar) is funded with at least $1 million from 21 Ventures. 3GSolar (website: www.3gsolar.com) is also funded by Quercus Trust and Israel Chief Scientist Office. 3GSolar president and founder Jonathan Goldstein was one of the senior scientists at the Luz solar energy company. Vesta Capital Corporation, traded on Canada’s TSX has signed a letter of intent (LOI) in Nov 2008 to acquire 3G for $10M in what looks like a reverse merger to take the Israeli firm public. If successful, this would make 3GSolar the first Israel-based company listed on a Canadian stock exchange.

Note: This hasn’t happened yet but in this Inter Solar brochure, 3GSolar, which has 19 employees, said that “In November 2008, 3GSolar was offered the opportunity to access public markets through acquisition by Vesta Capital Corp. 3GSolar has seized this opportunity and, lead by underwriter Canaccord, is in mid-process of completing the acquisition towards raising funds on the Toronto Exchange. Private placement by VC funds and investors is still of interest to 3GSolar, whether before, as part of or after its acquisition by Vesta Capital Corp.” So, anyone interested?

Another interesting article on 3GSolar:
Israeli company leading next generation of solar technology