Developing an LCD vulnerable electricity that can control the string rate rate with light: Expectations for application to a photo capacitor

光照射で比誘電率が約100倍も変化、応答時間も数秒以下

　Institute of RIKEN (RIKEN) Founding Practical Science Research Center Soft Matter Hiroya Nishikawa Special Researcher and Team Leader Araoka Respond in March 2022 and responded to visible light and had about 100 times more expedition rate.It has been announced that it has developed a changing liquid crystal vitality.It is said that if this material is inserted with an electrode, a photo condenser element can be realized.

　Recently discovered nematic LCDs have a rhena, more than 10,000, as an organic molecule, and are expected to be applied to energy materials and robotics materials.However, it is said that the principle of protrusions has not yet been elucidated.

　This time, the research team is a dye with a "AZO-F", a "AZO-F", which shows a light yielding reaction with visible light, as a material of a dioxan fluid-based liquid crystal compound called "DIO" called "DIO".Is added a small amount.

　Azo-Fを添加した強誘電性ネマチック液晶は、緑色の光（波長500〜550nm）を照射すると比誘電率が減少。逆に青色の光（波長400〜450nm）を照射すると比誘電率が増加した。Azo-Fを4％混合した強誘電性ネマチック液晶の特性を評価したところ、光を照射する前の比誘電率は最大値で約1万8000（ε_max）であった。

　これに緑色の光（波長525nm、180mWcm^-2）を30秒間照射すると、比誘電率は最小値で約200（ε_min）まで下がった。さらに、青色の光（波長415nm、7mWcm^-2）を30秒間照射すると、比誘電率はほぼ1万8000に回復することが分かった。比誘電率の変化率（ε_max-ε_min）/ε_maxは99.5％と極めて高い。

　If the green and blue light are irradiated alternately, they can change vigorously and repeat as many times as they are.This time, I confirmed the repetition of about 100 times.It was found that using a strong light such as a laser would change in a response time of a few seconds or less.

　How the fermented nematic liquid crystal changes the state due to light irradiation by observing the UV-visual absorption division of lighting, X-ray folding method, and an observation of the X-ray microscope.When the green light is irradiated, the AZO-F becomes a state called "Sith body", and transfers to a normal nematic LCD that is not a fermented electricity.

　On the other hand, when the blue light was irradiated, it was found that AZO-F was called a "transformer" and restored the fermentation state.These results revealed that fermentation nematic LCDs were involved in the expression of fermentation of fermentation of the local direction of molecules.

　研究チームは、平たんなITO電極に光応答性強誘電性ネマチック液晶を挟み込んだ「液晶セル（平行平板コンデンサー）」を作製し、その特性を評価した。電極面積50mm²、電極間距離17.8μmの液晶セルでは、約4nFから360nFまで静電容量を光制御できることが分かった。

　Furthermore, in order to confirm the operation at the practical level, the prototyped photo capacitor was incorporated into the electric oscillation circuit and evaluated in an environment in which light was irradiated.As a result, the oscillation frequency could be changed in the range of 100Hz to 8.5 kHz.

　In this experiment, the material that required heat was used.Already, a protrusion -based Nematic LCD that can be used at room temperature has been developed, and it is expected that a photo condenser with room temperature operation can be realized.