光合成系における光電荷分離を如何に長く行なうかが研究のポイント。光で電子を励起して再結合させない工夫が必要である。
それには効率良い分子群の配列が重要であるが難しい！水溶液中におけるSelf-assemblyテクニックが可能にするのかな？
iis.u-tokyo.ac.jp/Labs/wata_lab/photosynthesis
太陽エネルギーはジャガイモデンプンで蓄える（化学エネルギー）のが一番なのですが。シュタイナーの神秘科学で述べると興味深い。
pubs.rsc.org/en/content/articlelanding/2012/cs/c2cs35223k#!divAbstract
グノームたちは植物存在を上方へと押し上げ、ウンディーネたちが、いわば四方八方からやってきて、植物を取り巻く、夢のような意識のなかで、いわゆる宇宙化学者である証を見せなければ、植物存在は干からびてしまう。
ウンディーネたちは、素材の結合（融合）と分離（分裂）を夢見る。
そして植物が夢のなかに生き、上方へ向かって、地上を去り、成長していく、このウンディーネの夢こそが、植物のなかで、葉をつけ、葉から発し、素材の秘密に満ちた結合と分離を引き起こす宇宙化学者と呼ぶべき存在である。
従って、ウンディーネは植物の生の化学者と言える。
ウンディーネは化学を夢見る。これはウンディーネのなかの極めて繊細な霊性で、実際、水と空気が触れ合う場所にもつ霊性の要素である。
植物の化学工場である光合成を人類が真似するのはとても難しい。
Chemists devise technology that could transform
solar energy storage
Date: June 19, 2015 sciencedaily.com
Source: University of California - Los Angeles
Summary: Chemists have developed a major improvement to capture and retain energy from sunlight, where the stored energy can last dramatically longer than current solar technology allows -- up to several weeks, instead of the microseconds found in today's rooftop solar panels.
The materials in most of today's residential rooftop solar panels can store energy from the sun for only a few microseconds at a time. A new technology developed by chemists at UCLA is capable of storing solar energy for up to several weeks -- an advance that could change the way scientists think about designing solar cells.
The findings are published June 19 in the journal Science.
The new design is inspired by the way that plants generate energy through photosynthesis.
'Biology does a very good job of creating energy from sunlight,'
said Sarah Tolbert, a UCLA professor of chemistry and one of the senior authors of the research.
'Plants do this through photosynthesis with extremely high efficiency.'
'In photosynthesis, plants that are exposed to sunlight use carefully organized nanoscale structures within their cells to rapidly separate charges -- pulling electrons away from the positively charged molecule that is left behind, and keeping positive and negative charges separated,'
Tolbert said.
'That separation is the key to making the process so efficient.'
To capture energy from sunlight, conventional rooftop solar cells use silicon, a fairly expensive material.
There is currently a big push to make lower-cost solar cells using plastics, rather than silicon, but today's plastic solar cells are relatively inefficient, in large part because the separated positive and negative electric charges often recombine before they can become electrical energy.
'Modern plastic solar cells don't have well-defined structures like plants do because we never knew how to make them before,'
Tolbert said.
'But this new system pulls charges apart and keeps them separated for days, or even weeks. Once you make the right structure, you can vastly improve the retention of energy.'
The two components that make the UCLA-developed system work are a polymer donor and a nano-scale fullerene acceptor. The polymer donor absorbs sunlight and passes electrons to the fullerene acceptor; the process generates electrical energy.
The plastic materials, called organic photovoltaics, are typically organized like a plate of cooked pasta -- a disorganized mass of long, skinny polymer 'spaghettiスパゲッティ' with random fullerene 'meatballs.'
But this arrangement makes it difficult to get current out of the cell because the electrons sometimes hop back to the polymer spaghetti and are lost.
The UCLA technology arranges the elements more neatly -- like small bundles of uncooked spaghetti with precisely placed meatballs.
Some fullerene meatballs are designed to sit inside the spaghetti bundles, but others are forced to stay on the outside.
The fullerenes inside the structure take electrons from the polymers and toss them to the outside fullerene, which can effectively keep the electrons away from the polymer for weeks.
'When the charges never come back together, the system works far better,'
said Benjamin Schwartz, a UCLA professor of chemistry and another senior co-author.
In the new system, the materials self-assemble just by being placed in close proximity.
'We worked really hard to design something so we don't have to work very hard,'
Tolbert said.
The new design is also more environmentally friendly than current technology, because the materials can assemble in water instead of more toxic organic solutions that are widely used today.
'Once you make the materials, you can dump them into water and they assemble into the appropriate structure because of the way the materials are designed,'
Schwartz said.
'So there's no additional work.'
The researchers are already working on how to incorporate the technology into actual solar cells.
Yves Rubin, a UCLA professor of chemistry and another senior co-author of the study, led the team that created the uniquely designed molecules.
'We don't have these materials in a real device yet; this is all in solution,'
he said.
'When we can put them together and make a closed circuit, then we will really be somewhere.'