TiO2与ZnO复合纳米结构电极的光电化学研究

利用尿素加压共沉淀法以Ti(SO4)2与Zn(NO3)2为原料制备了TiO2-ZnO复合纳米粒子, 其纳米结构电极的光电化学研究结果表明, 反应物摩尔比为3∶1, 于530 ℃煅烧制备的复合纳米结构电极的光电转换效率最高. 对吸附染料RuL2(SCN)2∶2TBA的纳米结构TiO2和各种复合纳米粒子的纳米结构电极进行光电研究的结果表明, 染料对各纳米结构电极都起到了敏化作用, 其中也是由反应物摩尔比为3∶1, 于530 ℃煅烧制备的纳米结构电极的光电转换效率最高. 对聚3-甲基噻吩修饰的纳米结构TiO2和摩尔比为3∶1, 于530 ℃煅烧的复合纳米粒子构成的纳米结构电极进行光电性能研究, 结果表明, 聚3-甲基噻吩与半导体纳米粒子之间存在p-n结, 在一定条件下p-n结的存在有利于光生电子/空穴的分离, 从而提高了光电转化效率.     

聚噻吩的光电化学研究

导电聚合物是由一些具有共轭π键的聚合物经化学或电化学掺杂后形成的导电率可从绝缘体延伸到导体范围的一类高分子材料。其中噻吩及其衍生物具有导电率高、环境稳定性好、成膜性好、禁带宽度小等特点,是用做光伏电池的理想材料。相继报道的有聚3-甲噻吩[1]、聚3-己基噻吩[2],聚(3-十一烷基-2,2’-并噻吩)[3]等。对于聚噻吩的光电化学性质的研究,在国际上很少见报道,国内尚未见报道,本文对聚噻吩(PTh)的光电化学性质进行了研究。1实验部分1.1仪器与试剂光电化学实验采用带石英窗口的三电极电解池,工作电极为ITO/PTh膜电极,参比电极为饱和…     

聚3-甲基噻吩及聚3-己基噻吩修饰钛酸盐纳米管的光电化学性能研究

采用水热法制备了钛酸盐纳米管, 并将钛酸盐纳米管制备成纳米结构电极进行光电化学研究. 钛酸盐纳米管产生阳极光电流, 具有n-型半导体特性. 结果表明, 聚3-甲基噻吩[poly(3-methylthiophene), PMeT]、聚3-己基噻吩[poly(3-hexylthiophene), P3HT]修饰钛酸盐纳米管后产生的光电流均较纯钛酸盐纳米管的光电流高, 且使产生光电流的波长向长波区移动. 钛酸盐纳米管/PMeT、钛酸盐纳米管/P3HT的光电转换效率分别达11.40%, 0.91%(未校正光子损失). 钛酸盐纳米管/PMeT的光电转换效率较钛酸盐纳米管/P3HT的光电转换效率高10.5%. 钛酸盐纳米管/PMeT、钛酸盐纳米管/P3HT中存在p-n异质结, 在一定条件下p-n异质结的存在有利于光生电子/空穴的分离.     

纳米结构TiO2/聚3-己基噻吩多孔膜电极光电性能研究

用光电流作用谱、光电流-电势图等光电化学方法研究了ITO/聚3-己基噻吩(ITO/ P3HT)膜和纳米结构TiO2/聚3-己基噻吩(TiO2/P3HT)复合膜的光电转换性质. 结果表明, P3HT膜的禁带宽度为1.89 eV, 价带位置为－5.4 eV. 在ITO/TiO2/ P3HT复合膜电极中存在p-n异质结, 在一定条件下异质结的存在有利于光生电子-空穴对的分离. P3HT修饰ITO/TiO2电极可使光电流发生明显的红移, 从而提高了宽禁带半导体的光电转换效率.     

Ru(II)染料与聚3-甲基噻吩复合敏化纳米结构TiO_2电极的光电化学研究

利用光电流作用谱、循环伏安等光电化学方法研究了染料RuL2(SCN)2:2TBA(L=2,2'-bipydine-4,4'-dicarboxylicacid)与聚3-甲基噻吩(P3MT)复合敏化电极的光电化学性质.RuL2(SCN)2:2TBA/P3MT复合敏化TiO2纳米晶多孔膜电极比染料RuL2(SCN)2:2TBA敏化TiO2纳米结构电极的光电转换效率大幅度提高.复合敏化电极中存在p-n异质结有效地抑制了电子的反向复合,减少了电子的损失.     

聚噻吩类导电聚合物及其复合膜修饰电极的制备及其在电分析化学中的应用

聚噻吩类导电聚合物修饰电极在电化学检测某些生物分子方面显示出独特的优势,尤其是聚(3-甲基噻吩)(P3MT)修饰电极,这是因为3-甲基噻吩易于电聚合成膜,得到的导电薄膜电导率高、电催化效果好、稳定性高、耐用、抗污染,而且还具有很好的选择性和灵敏性.     

3-烷基噻吩交替共聚物的合成及其电化学性质

通过Heck偶联法合成了4种3-烷基噻吩交替共聚物:聚(2,4-二乙烯基-3-己基噻吩-1,3,4-二唑)(P3HT-OXD)、聚(2,4-二乙烯基-3-辛基噻吩-1,3,4-二唑)(P3OT-OXD)、聚(2,4-二乙烯基-3-己基噻吩-吡啶)(P3HT-Py)和聚(2,4-二乙烯基-3-辛基噻吩-吡啶)(P3OT-Py). 用NMR、GPC等测试技术对其结构进行了表征. 采用循环伏安法、紫外-可见吸收光谱法研究了系列共聚物光电性能. 结果表明,随噻吩环3位取代烷基碳链的增长,聚合物电离能(Ip)减小,带隙(Eg)也随之变窄. 其中,P3OT-OXD的Eg比P3HT-OXD小0.11 eV,P3OT-Py的Eg比P3HT-Py小0.19 eV,在3-烷基噻吩聚合物主链上引入吸电子能力较强的二唑单元,可有效提高共聚物电子亲合能(Ea),对提高电子传输能力,改善电子与空穴注入平衡有积极作用.     

3-甲基噻吩和3-氯噻吩的电化学共聚

3-甲基噻吩和3-氯噻吩首次三氟化硼乙醚溶液中实现了电化学共聚。共聚物的分子结构通过电化学分析、红外和拉曼光谱得到了证实。实验结果表明：单体投料比对共聚物的结构和电化学性质有很大的影响;共聚物比3-甲基噻吩和3-氯噻吩的均聚物具有更大的充放电电容和更可逆的氧化还原性质。     

导电聚合物的现场电导/电化学研究——聚(3-甲基噻吩)和聚噻吩

本文提出一种研究导电聚合物的现场电位、电导测量/电化学方法。该实验方法基于一种可重复使用的玻璃碳-碳纤维组双电极。用该方法研究了聚(3-甲基噻吩)和聚噻吩的现场电位、电导/电化学行为。     

甲基噻吩在HY分子筛上的吸附、脱附及转化行为

由NH₄Y分子筛制备了HY分子筛,运用N₂吸附、NH₃-TPD和Py-FTIR等手段表征HY分子筛的物化性能;采用智能重量分析仪(IGA)方法研究了甲基噻吩(2-甲基噻吩、3-甲基噻吩)在HY分子筛上的吸附-脱附行为;采用程序升温脱附-质谱(TPD-MS)联用手段研究了甲基噻吩在HY分子筛上的转化行为。结果表明,在200 ℃下 2-甲基噻吩和3-甲基噻吩在HY分子筛中的强B酸上发生强化学吸附作用,与B酸结合后生成了甲基噻吩的碳正离子结构进而发生了歧化反应、脱烷基反应以及裂化反应;与2-甲基噻吩不同的是,3-甲基噻吩与HY通过一定的氢转移反应生成了3-甲基四氢噻吩,且200 ℃吸附条件下3-甲基噻吩比2-甲基噻吩更容易发生裂化反应。     

纳米结构TiO2/聚3-甲基噻吩多孔膜电极光电化学研究

用光电流作用谱、光电流-电势图、紫外-可见吸收光谱等光电化学方法研究了导电玻璃(ITO)/TiO₂/聚3-甲基噻吩(PMT)电极的光电转换性质. 结果表明, PMT膜为p型半导体, 其禁带宽度为1.93 eV. 并通过循环伏安和光电化学方法确定了其导带位置为－3.44 eV, 价带为－5.37 eV, 在纳米TiO₂与PMT之间存在p-n异质结, ITO/TiO₂/PMT电极不仅提高了光电流, 而且使产生光电流的起始波长红移至＞600 nm, 从而提高了宽禁带半导体的光电转换效率.     

3-己基噻吩和2-噻吩甲酸共聚物修饰纳米结构TiO2薄膜电极的光电性能研究

用光电流作用谱、光电流-电势图等光电化学方法研究了铟锡导电玻璃(ITO)/3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)膜电极以及ITO/TiO₂/3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)复合膜电极的光电转换性质. 结果表明, CTCHT膜为p-型半导体, 禁带宽度为2.44 eV, 价带位置为－5.73 eV. 研究表明在ITO/TiO₂/CTCHT复合膜电极中存在p-n异质结, p-n异质结的存在能够使光生电子和空穴有效的分离, 有效地降低了电荷的反向复合几率, 提高了光电转换效率, CTCHT膜修饰ITO/TiO₂电极可使光电流增强, 使宽禁带半导体电极的光电转换效率得到改善.     

纳米结构TiO2/3-甲基噻吩和2-噻吩甲酸共聚物复合膜电极光电化学性能

用光电流作用谱、光电流-电势图等光电化学方法研究了ITO/3-甲基噻吩和2-噻吩甲酸共聚物(CTCMT)膜电极和ITO/TiO₂/CTCMT复合膜电极的光电转换性质.结果表明,CTCMT膜为p型半导体,禁带宽度为2.36eV,价带位置为-5.52eV.在ITO/TiO₂/CTCMT复合膜电极中存在p-n异质结,在一定条件下异质结的存在有利于光生电子-空穴对的分离.CTCMT膜修饰ITO/TiO₂电极可使光电流增强,光电流起始波长红移至600nm以上,使宽禁带半导体电极的光电转换效率得到改善.     

Electronic band structure of titania semiconductor nanosheets revealed by electrochemical and photoelectrochemical studies

Electrochemical and photoelectrochemical studies were conducted on self-assembled multilayer films of titania nanosheets on a conductive ITO substrate. Cyclic voltammogram (CV) curves indicated that the titania nanosheet electrode underwent insertion/extraction of Li(+) ions into/from the nanosheet galleries, associated with reduction/oxidation of Ti(4+)/Ti(3+). These processes accompanied reversible changes in UV-vis absorption of the titania nanosheet electrodes. Applying a negative bias of -1.3 V (vs Ag/Ag(+)) and lower brought about absorption reduction where the wavelength is shorter than 323 nm, and vice versa, indicating a flat-band potential of (approximately) -1.3 V and a band gap energy of 3.84 eV. Photocurrents were generated from the titania nanosheet electrodes under a positive bias. The onset potential for photocurrent generation from the titania nanosheet electrodes was around -1.27 V, and the band gap energy estimated from the photocurrent action spectra was 3.82 eV, in excellent agreement with the values obtained from the spectroelectrochemical data. The lack of difference in the band gap energies for titania nanosheet electrodes with different numbers of layers suggests that a nanosheet is electronically isolated in multilayer assemblies without affecting the electronic state of neighboring nanosheets. Similar measurements on the anatase-type TiO(2) electrode revealed that the lower edge of the conduction band for the titania nanosheet is approximately 0.1 V higher than that for anatase, while the upper edge of the valence band is 0.5 V lower.     

Syntheses and X-ray diffraction, photochemical, and optical characterization of Cu2SixSn1-xS3 (0.4 < or = x < or = 0.6) for photovoltaic applications

The study of the pseudobinary system Cu(2)SnS(3-)Cu(2)SiS(3) shows that a solid solution (Cu(2)Si(x)Sn(1-x)S(3)) exists in the range 0.4 < or = Si/(Sn+Si) < or = 0.6. Based on diffuse reflectance and photoelectrochemical measurements these compounds show potential as absorber materials for photovoltaic devices. The compounds were prepared at 850 degrees C from copper sulfide, silicon, tin, and sulfur and were analyzed with single-crystal (for x approximately 0.40) and powder diffraction techniques. Optical band gaps of 1.25, 1.35, and 1.45 eV were observed for the three compositions x = 0.39, 0.48, and 0.61; cathodic photocurrent occurring is significant.     

Tetra-EDOT substituted 3D electrochromic polymers with lower band gaps

A couple of novel electrochromic materials poly(2,3,4,5-tetrakis(2,3-hydrothieno[3,4-b]dixin-5-yl)-1-methyl-1H-pyrrole)(P(t-EDOT-mPy))and poly(5,5',5",5'"-(thiophene-2,3,4,5-tetrayl)tetrakis(2,3-dihydrothieno[3,4-b][1,4]dioxine))(P(t-EDOTTh))are electrodeposited via multi-position polymerization of their tetra-EDOT substituted monomers t-EDOT-mPy and t-EDOT-Th,respectively.Compared with the linear 2D structured poly(thiophene)(E_g=2.2 eV)and poly(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophene)(E_g=1.7eV),P(t-EDOT-Th)(E_g=1.62eV)has the lowest band gap.Hence,we speculate that the band gaps of the two polymers,having 3D structures,are decreased in contrast to non-substituted polymers or bi-EDOT substituted polymers,thiophene and 1-methyl-1H-pyrrole.The results indicated that P(t-EDOT-Th)thin films are more stable and show higher transmittance amid two polymers,which may find their utilization in organic optoelectronics.     

Regioregular copolymers of 3-alkoxythiophene and their photovoltaic application

Low band gap conjugated polymers with proper energy levels for charge transfer are required to achieve high-efficiency polymer solar cells. We report the synthesis and characterization of two new regioregular copolymers that are based on 3-alkoxythiophene monomers: poly(3-octylthiophene-2,5-diyl-co-3-decyloxythiophene-2,5-diyl) (POT-co-DOT) and poly{(9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-decyloxythien-2-yl)-2,1,3-benzothiadiazole]-5',5' '-diyl} (PF-co-DTB). Compared to the alkyl substituents, the alkoxy side chains on the thiophene units can effectively lower the band gap of copolymers and enhance the charge transfer to electron acceptors such as (6,6)-phenyl C(61)-butyric acid methyl ester (PCBM). The chemical structure and regioregularity of the copolymers were confirmed by NMR. Both copolymers are readily soluble in organic solvents and form high-quality thin films. Electrochemical and photophysical studies reveal band gaps of 1.64 eV for POT-co-DOT and 1.78 eV for PF-co-DTB. Bulk heterojunction photovoltaic devices were fabricated using blends of these copolymers with PCBM as the active layer, ITO-glass as the anode, and aluminum as the cathode. Power conversion efficiency of 1.6% was obtained under simulated solar light AM 1.5 G (100 mW/cm(2)) from a solar cell with an active layer containing 20 wt % PF-co-DTB and 80 wt % PCBM. Regioregular poly(3-decyloxythiophene-2,5-diyl) (P3DOT) was also studied for comparison purposes.