有機アミン／酸化亜鉛ナノコンポジットの合成と有機太陽電池への応用

金沢大学理工研究域物質化学系本研究室ではこれまでに、金属酸化物やアミノ化合物を用いた様々な電子捕集層や捕集電極を開発し、これらを用いた高耐久な素子の大気下作製に成功している。酸化亜鉛は電子捕集層として広く用いられているが、膜表面及び膜中に水酸基が存在しており、水酸基由来のエネルギー準位が光励起により生じた電子のトラップ準位となると考えられている。近年、アミノ化合物を酸化亜鉛に混ぜ込むことで水酸基由来のトラップが減少し、電荷モビリティや素子性能が向上したことが報告されている。そこで本研究では種々アミノ化合物を酸化亜鉛に混ぜ込んだナノ複合体膜を電子捕集層に用いることで、高性能かつ高耐久な素子の作製を試みた。洗浄済みのITO基板上に、sol-gel法により酸化亜鉛/アミンナノ複合体膜を製膜した。その後、有機発電層としてP3HT:PCBM、正孔捕集層としてPEDOT:PSSをスピンコート法により順に製膜し、正孔捕集極としてAuを真空蒸着した。最後に熱アニールを兼ねて被覆材の熱圧着を施すことで素子の完成とした。この素子に擬似太陽光(AM1.5G-100 mW cm-2)を照射しながら電流-電圧(I-V)曲線を測定し、性能評価を行った。白色光照射120分後における各素子の光電変換特性は、ZnOを電子捕集層に用いた素子のPCEは3.12 %であったが、PEI(B)を混ぜ込んだ素子ではJSC値の増加が見られ、PCEが1割程度増加した。BAPではJSC値や素子性能の向上は見られず、分子量が低分子であるためにナノ複合体膜中のBAPの残存率が低く、その結果BAPが十分に機能していないことが示唆された。また原子間力顕微鏡でZnO:PEI(B)ナノ複合体膜表面を観察したところ膜の表面形状の変化が観察され、これによる光閉じ込め効果が期待されこのことがJSC値の向上に大きく寄与していると考察した。研究課題/領域番号:16K04929, 研究期間(年度):2016-04-01 – 2019-03-3

逆型有機薄膜太陽電池の劣化機構解析と高耐久性素子の開発

金沢大学物質化学系本研究では、我々がこれまでに報告している逆型有機薄膜太陽電池(ITO/n型半導体/PCBM : P3HT/PEDOT : PSS/Au素子)の新たな評価方法として、交流インピーダンス法(IS)を適用し、太陽電池の性能劣化因子の解明を行った。本年度は硫化亜鉛(ZnS)を電子捕集層に用いたFTO/ZnS/PCBM : P3HT/PEDOT : PSS/Au逆型素子について研究を行い、ZnS表面をHS-イオンで化学修飾したときの光電変換特性と光IS特性を評価した。ZnS表面をHS-イオンで被覆することによって、素子性能が40%向上した。光IS測定により、本逆型素子に存在する成分のうち、ZnS層およびPCBM : P3HT層に電気容量成分があることが確認された。ZnS表面修飾により抵抗成分の減少が観察され、等価回路を用いたfittingの結果から、これはZnS/PCBM界面における電荷移動抵抗が増加したためと帰属された。この界面では、アクセプターPCBMとドナーP3HTの間の光誘起電子移動によって生成した電子が、PCBMのLUMOレベルからZnSの伝導帯へ移動する際の界面抵抗と考えられる。したがって、化学吸着のような界面修飾手法で界面輸送効率を改善することが性能向上のために有効であることを明確に示すことが出来た。また、連続光照射下における光IS測定から、ZnS/PCBM界面の電荷移動抵抗の増加が観測された。この抵抗増加は、ZnS表面での光触媒効果により、ZnS表面付近の有機膜が劣化したためと考えられる。このように、光IS法を用いることにより、光電流電圧曲線から得られた光電変換特性をより詳細に解析でき、性能の向上および劣化がどの界面およびバルクに由来するのか帰属することができた。研究課題/領域番号:20850018, 研究期間(年度):2008出典：研究課題「逆型有機薄膜太陽電池の劣化機構解析と高耐久性素子の開発」課題番号20850018（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-20850018/）を加工して作

Inverted type bulk-heterojunction organic solar cell using electrodeposited titanium oxide thin films as electron collector electrode

金沢大学理工研究域物質化学系We developed an inverted type bulk-heterojunction organic solar cell with 1 cm2 active area using a fluorine-doped tin oxide/electrodeposited amorphous (TiOx) or anatase (TiO2) titanium oxide electrode instead of the low work-functional electrode such as Al. The cell with TiO2 showed the power conversion efficiency (η) of 2.5% by irradiating AM 1.5-100 mW cm- 2 simulated sunlight. While, the performance of the cell with TiOx was almost maintained in an ambient atmosphere under continuous light irradiation of 10 h, although slightly small initial η value of 2.1% was observed. Crown Copyright © 2008

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

Initial Results for Science Instruments Onboard EQUULEUS During the Cruising Phase Toward the Earth Moon Lagrange Point

EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) is a spacecraft to explore the cis-lunar region including the Earth-Moon Lagrange point L2 (EML2). The spacecraft is being jointly developed by JAXA, the University of Tokyo, and several other universities in Japan. After being launched into a lunar transfer orbit by NASA\u27s SLS (Space Launch System) Artemis-1 on November 16, 2022, the spacecraft successfully performed a first Delta-V and a trajectory correction maneuver. This enabled a precise lunar flyby and successful insertion into the orbit toward EML2. Although the size of EQUULEUS is only 6U CubeSat, the spacecraft carries three different science instruments. The spacecraft can effectively demonstrate science missions during and after the flight to EML2 by using these instruments; the plasmasphere observation around the Earth by PHOENIX, the space dust flux detection in the cis-lunar region by CLOTH, and the lunar impact flash (LIF) observation at the far side of the moon by DELPHINUS. All instruments have already completed its checkout. During the cruising phase, PHOENIX conducted Earth observations and successfully identified the Earth\u27s plasmashere. CLOTH has started regular standby operations. DELPHINUS obtained impressive images such as the far side of the Moon at lunar closest approach and long-period comet, Comet ZTF. This poster presents the details of these scientific missions and the initial checkout and observation results of the science instruments

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

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

Highly durable inverted-type organic solar cell using amorphous titanium oxide as electron collection electrode inserted between ITO and organic layer

金沢大学理工研究域物質化学