キノンを有する亜鉛ポルフィリン薄膜の光電気化学的性質

金沢大学工学部研究課題/領域番号:02750591, 研究期間(年度):1990出典：研究課題「キノンを有する亜鉛ポルフィリン薄膜の光電気化学的性質」課題番号02750591（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-02750591/）を加工して作

ドナー性およびアクセプター性共役高分子ブレンド膜太陽電池の色素増感による高効率化

[1]Al/ポリチオフェン・ショットキーバリア型光電変換素子のポルフィリン色素による増感効果の検討p型半導体であり正孔移動度の比較的大きな立体規則性共役ポリマー:ポリ(3-ヘキシルチオフェン)(P3HT)を用いた太陽電池に対して、光吸収率を大きくすることでエネルギー変換効率の向上が見込めるかどうかを検討した。その結果、P3HTにポルフィリン色素やメロシアニン色素をブレンドすることによって、P3HTあるいは色素単独膜を用いた場合よりも数十倍大きな光電流が流れ、格段に良いエネルギー変換効率を得た。この理由を明らかにするために、特に、酸化還元電位や立体的構造を設計・合成しやすいポルフィリン色素をP3HTにブレンドした薄膜素子を用いて詳細に検討した。その結果、ポルフィリンからP3HTへの光誘起ホール移動が起こる場合に光電流の増加が顕著になることが判明した。[2]平滑透明TiO_2電極を用いた有機薄膜太陽電池の検討前節では、Al/有機薄膜/Auサンドイッチ型素子を用いているため、半透明Al電極側から光照射した場合には光のロスが大きいこと、また、湿気がある所でこの素子を作動させるとAlの光腐食が起こることが、このタイプの素子を実用電池とする場合に大問題となる。そこで、透明平滑TiO_2電極をAl電極の代わりに電子輸送電極として用いた。(1)TiO_2/ポリチオフェン/Auサンドイッチ型太陽電池のメロシアニン色素ブレンドによる光電流の増加本研究では、平滑で透明な酸化チタン薄膜を用いたTiO_2/ポリチオフェン界面を有する有機薄膜太陽電池の光利用率を向上させる目的で、共役ポリマーであるポリチオフェンにメロシアニン色素NK2684をブレンドした。さらに、電荷分離を促進するTiO_2/有機膜界面の空乏層領域について詳細に検討を加えた。平滑で透明なTiO_2電極上にP3HTを塗布したTiO_2/P3HT/Auサンドイッチ型太陽電池のP3HTにメロシアニン色素をブレンドすることによって、電池性能が大幅に向上し、太陽擬似光AM1,5-100mWcm^の照射下、エネルギー変換効率0.32%を得た。光電流発生界面TiO_2/P3HT+NK2684における有機固体側の電荷分離領域は、光照射下では光電流の光学的フィルター効果により40nm以上と見積もられた。この比較的広い範囲の電荷分離領域では、P3HTと色素の光誘起分子間電荷移動によって生じたホールと電子が効率よく電荷分離するために、このタイプの太陽電池としては大きなエネルギー変換効率が得られた。(2)TiO_2/ポリフェニレンビニレン/Auサンドイッチ型太陽電池のDCM化合物ブレンドによる電池性能の向上本研究では、TiO_2/ポリ[2-メトキシ-5-(2\u27-エチレンヘキシルオキシ)-1,4-フェニレンビニレン(MEH-PPV)からなる太陽電池を検討した。この太陽電池のMEH-PPV層にアクセプター色素DCMをブレンドしたときに著しい電池性能の向上が見られ、太陽擬似光AM1.5-100mWcm^照射下でエネルギー変換効率0.47%が得られた。[1]Sensitization effect of porphyrin dye on photocurrent of Al/polythiophene Schottky-barrier cellsWe prepared organic solar cells consisting of a blend of soluble conjugated polymer as better charge-transport material and dye as more effective light-harvesting material. We clarified the photocurrent enhancement in the Al/P3HT+porphyrin Schottky-barrier solar cell and the enhanced mechanism, where P3HT is a regioregular polythiophene. Various porphyrins with different substituents were employed in the cell to examine which factors are dominant for the photocurrent enhancement. The photocurrent for irradiation from the Al side was much larger for the blend cell of porphyrin+P3HT than for the pure cell of porphyrin or P3HT. The photo-charge separation mainly occurred in the narrow region of about 15 nm of organic solid side at the Al/organic solid interfaces, where the electric field was as large as 10^5 Vcm^. That is, photons absorbed in the narrow organic solid layer which has the potential gradient were effectively used for the photocurrent generation. However, the observed photocurrent enhancement was not attributed to the magnitude o」 the electric field at the Al/organic solid interface, but to the ease of the photoinduced hole-transfer from porphyrin to P3HT. That is, when the thermodynamic driving force of the hole-transfer was large and the distance between conjugated planes of porphyrin and P3HT was short, remarkable photocurrent enhancement was observed.[2]Photocurrent enhancement in TiO_2/polythiophene+merocyanine/Au solid-state solar cellsA solar cell consisting of a transparent and flat, that is, non-porous TiO_2 film as the electron-transporting layer and a conjugated regioregular polythiophene as the hole-transporting layer was investigated. When a merocyanine dye was blended into the regioregular polythiophene (P3HT) in the TiO_2/P3HT/Au sandwich-type solar cell, the cell performance was remarkably enhanced, resulting in 0.32 % of energy conversion yield under the irradiation of AM1.5-100mWcm^. Further, the photo-voltaic mechanism was discussed on the base of the energy level diagram of the component materials before contact and so-called an optical filtering effect of the photocurrent. The depletion layer for the photo-charge separation lies in the blended solid side at the TiO_2/merocyanine+P3HT interface, and the film thickness of more than 40nm is estimated as the region.[3]Performance enhancement by blending an electron acceptor in TiO_2/polyphenylenevinylene/Au solid-state solar cellsA solar cell consisting of a transparent and flat, that is, non-porous TiO_2 film as an n-type semiconductor and a conjugated polymer MEH-PPV as a p-type semiconductor was investigated. When [2-[2-[4-(dimethylamino)phenyl]ethenyl]-6-methyl-4H-pyran-4-ylidene]propanedinitrile (DCM) as an electron acceptor was blended into poly[2-methoxy-5-(2\u27-ethylenehexyloxy)-1,4-phenylenevinylene (MEH-PPV) as a donor in the TiO_2/MEH-PPV/Au sandwich-type solar cell, the cell performance was remarkably enhanced. After all, the energy conversion yield resulted in 0.47 % under the irradiation of AM1.5-100mWcm^.研究課題/領域番号:14580536, 研究期間(年度):2002-2004出典：「ドナー性およびアクセプター性共役高分子ブレンド膜太陽電池の色素増感による高効率化」研究成果報告書　課題番号14580536 (KAKEN：科学研究費助成事業データベース（国立情報学研究所）)　　　本文データは著者版報告書より作

メロシアニン色素薄膜電極を用いた電気化学光電池の光電流発生機構の解明

金沢大学工学部研究課題/領域番号60750762, 研究期間(年度):1985出典：研究課題「メロシアニン色素薄膜電極を用いた電気化学光電池の光電流発生機構の解明」課題番号60750762（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-60750762/）を加工して作

Flexible inverted polymer solar cells on polyethylene terephthalate substrate containing zinc oxide electron-collection-layer prepared by novel sol-gel method and low-temperature treatments

Flexible and air-stable polymer solar cells were fabricated on a polyethylene terephthalate (PET) substrate. The cell structure was indium tin oxide (ITO) on PET/zinc oxide (ZnO)/[6,6]-phenyl C 61butyric acid methyl ester (PCBM):regioregular poly(3-hexylthiophene) (P3HT)/poly (3,4-ethylenedioxylenethiophene):poly(4-styrene sulfonic acid) (PEDOT:PSS)/Au, this being called the ZnO cell. Reproducible cell performances were obtained despite the ZnO cells being fabricated in air and at low temperature, using a novel ZnO precursor solution containing zinc(II) acetylacetonate as a metal source and acetylacetone as a Zn 2+ complexing agent. The power conversion efficiency (PCE) of the flexible ZnO cells without sealing was 2.15% under irradiating AM1.5G simulated sunlight at 100 mW cm -2. In addition, the performance of the non-sealed ZnO cells was almost constant in ambient atmosphere under continuous light irradiation for 100 h. © 2012 Elsevier B.V. All rights reserved

Efficient organic solar cells by penetration of conjugated polymers into perylene pigments

金沢大学理工研究域物質化学系We report here efficient air-stable p-n heterojunction organic solar cells with a structure consisting of an n-type insoluble perylene pigment penetrated by a p-type-conjugated polymer, where the interfacial area for photocurrent generation increases. The solar cells are easily produced by infiltrating a soluble-conjugated polymer intentionally into an opening among insoluble microcrystalline perylene layer under a saturated chloroform vapor. This approach can be regarded as an alternative convenient way to achieve bulk heterojunction solar cells. The cell performance is further enhanced by inserting an additional layer between the electrode and the photoactive layer to confine exciton in the photoactive layer. The overall attempt to improve the cell performance, so far, results in maximum quantum efficiency up to 45% under illumination of 485-nm monochromatic light and power conversion efficiency up to 1.9% under a simulated solar light (AM1.5) with a 100 mW cm-2 intensity. The approach is promising to achieve practical efficiency because tuning the opening size can further widen the photoactive area. © 2004 American Institute of Physics

Contribution of electric-field-induced metal-free porphyrin dication to photocurrent in mixed solid of metal-free porphyrin and o-chloranil/Al Schottky-barrier cell

金沢大学大学院自然科学研究科先端機能物質Although a Al/H2tpp (5, 10, 15, 20-tetraphenylporphyrin) Schottky-barrier cell did not show a clear rectification property because of the large electric resistance of the H2tpp solid, the rectification property was remarkably improved when o-chloranil was added into the H2tpp solid. The short-circuit dark-current was observed for the Al/dye cells with the mixed solid in contrast to that with the pure H2tpp solid, and it increased with increasing molar ratio (R) of o-chloranil to H2tpp. Furthermore, a much larger photocurrent was observed for the mixed-solid cells than for the pure H2tpp cell, but in the former cells in contrast to the latter cell, the open-circuit photovoltage was approximately the same as the open-circuit dark-voltage. These results indicate that the photocurrent of the mixed-solid cells was from the photocorrosion of the Al electrode. The short-circuit photocurrent action spectra obtained by irradiating from the Al side followed the absorption spectra of the dye solid films on the Al substrate below the R value of about 1, but above R = 1.5, a clear difference was observed in the spectra. This difference arises because a small amount of metal-free porphyrin dications, which is hardly detected by UV-visible spectra, was produced in the immediate neighborhood of the Al electrode when spin-coated with a larger R value because of dark-corrosion of aluminum by both assistance of the hydrogen bonds (between H2tpp and o-chloranil) and the electric field (in a Schottky barrier built during the spin coating). Thus the metal-free porphyrin dications efficiently underwent a photoinduced charge-separation by the potential gradient in the Schottky barrier

Characterization of ZnS-layer-inserted bulk-heterojunction organic solar cells by ac impedance spectroscopy

金沢大学理工研究域物質化学系A fluorine-doped tin oxide (FTO)/zinc sulfide (ZnS)/[6,6]-phenyl C 61 butyric acid methyl ester (PCBM): regioregular poly(3-hexylthiophene) P3HT)/poly(3,4-ethylenedioxylenethiophene): poly(4-styrene sulfonic acid) (PEDOT:PSS)/Au type organic solar cell (FTO/ZnS/PCBM:P3HT/PEDOT:PSS/Au, ZnS cell) with a 1 cm2 active area was first developed using transparent ZnS prepared on a FTO electrode by a chemical bath deposition method. The ZnS inserted solar cells were investigated by photocurrent-voltage (I-V) and ac impedance spectroscopy (IS) measurements. In photo I-V measurements, the ZnS cell exhibited scattered power conversion efficiencies (η) of 0.7%-1.2% when the FTO/ZnS electrode was not immersed in various aqueous solutions before the fabrication of the ZnS cells. In contrast, the solar cells with a surface-modified FTO/ZnS electrode by immersing in 0.1M Na2 S solutions at pH 7-9 containing hydrosulfide ions (HS-) exhibited reproducible η of 1.5%-1.7%. The electric resistance components in the cell consisting of five layers were separately estimated by the IS measurement. The larger of the solar cell using HS- modified ZnS was explained by the fact that the charge transport resistance at the ZnS/PCBM:P3HT interface became smaller due to this surface modification. When a continuous light irradiation was carried out for the modified cells, the resistance at the ZnS/PCBM:P3HT interface increased, being accompanied by the decrease in the η. That is, the cell performance was controlled mainly by charge transport velocity at the ZnS/PCBM:P3HT interface. © 2009 American Institute of Physics

Flexible inverted polymer solar cells containing an amorphous titanium oxide electron collection electrode

An inverted polymer solar cell was fabricated on a polyethylene terephthalate (PET) substrate. The cell structure was ITO/amorphous titanium oxide (TiOx)/[6,6]-phenyl C61 butyric acid methyl ester (PCBM): regioregular poly(3-hexylthiophene) (P3HT)/poly(3,4-ethylenedioxylenethiophene):poly(4-styrene sulfonic acid) (PEDOT:PSS)/Au (TiOx cell). It was achieved using low boiling point diethyl amine (DEA) as a Ti4+ complexing agent, and high boiling point 1,2,3,4-tetrahydronaphthalene (Tetralin) containing 2 vol.% 1,8-octanedithiol (ODT) as the solvent for PCBM:P3HT film preparation. With heat treatment at 100°C, the use of DEA and Tetralin:ODT made it possible to prepare a TiOx electron collection layer and PCBM:P3HT photoactive layer, respectively. Fabricating the TiOx cell on the thin PET film was possible, as PET did not warp at 100°C. The power conversion efficiency (PCE) of the TiOx cell fabricated on PET was 2.43%, under AM1.5G conditions. When fabricated on glass, the PCE was 2.76%. When [6,6] diphenyl C62 bis(butyric acid methyl ester) (bis-PCBM) was instead used as the electron acceptor in the photoactive blend layer, the flexible air-stable cell provided a PCE of 2.81%. © 2010 Elsevier B.V

Inverted bulk-heterojunction organic solar cell using chemical bath deposited titanium oxide as electron collection layer

金沢大学理工研究域物質化学系Chemical bath deposited titanium oxide (TiOx ) as an electron collection layer is introduced between the organic layer and the indium tin oxide (ITO) electrode for improving the performance of inverted bulk-heterojunction organic thin film solar cells with 1 cm2 active area, where regioregular poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) were mainly used as the photo-active layer. The uniform and thin TiOx film was easily prepared onto the ITO electrode in air by simple chemical bath deposition method. The cell performance was almost maintained in an ambient atmosphere under continuous light irradiation of 100 h despite non-sealing. The cell with bulk-heterojunction organic thin film consisted of [6.6] diphenyl C62 bis(butyric acid methyl ester) (bis-PCBM) and P3HT prepared under best condition showed the power conversion efficiency (PCE) of 3.8% under the AM1.5G simulated sunlight. © 2010 Elsevier B.V. All rights reserved