scholarly journals Improving Interfacial Charge-Transfer Transitions in Nb-Doped TiO2 Electrodes with 7,7,8,8-Tetracyanoquinodimethane

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 367 ◽  
Author(s):  
Reo Eguchi ◽  
Yuya Takekuma ◽  
Tsuyoshi Ochiai ◽  
Morio Nagata
Keyword(s):  
Charge Transfer ◽  
Electron Transport ◽  
Tio2 Nanoparticles ◽  
Conduction Band ◽  
Charge Separation ◽  
Electron Injection ◽  
Tio2 Electrode ◽  
Interfacial Charge Transfer ◽  
Doped Tio2 ◽  
Interfacial Charge

Interfacial charge-transfer (ICT) transitions involved in charge-separation mechanisms are expected to enable efficient photovoltaic conversions through one-step charge-separation processes. With this in mind, the charge-transfer complex fabricated from TiO2 nanoparticles and 7,7,8,8-tetracyanoquinodimethane (TCNQ) has been applied to dye-sensitized solar cells. However, rapid carrier recombination from the conduction band of TiO2 to the highest occupied molecular orbital (HOMO) of TCNQ remains a major issue for this complex. In this study, to inhibit surface-complex recombinations, we prepared Nb-doped TiO2 nanoparticles with different atomic ratios for enhanced electron transport. To investigate the effects of doping on electron injection through ICT transitions, these materials were examined as photoelectrodes. When TiO2 was doped with 1.5 mol % Nb, the Fermi level of the TiO2 electrode shifted toward the conduction band minimum, which improved electron back-contact toward the HOMO of TCNQ. The enhancement in electron transport led to increases in both short circuit current and open circuit voltage, resulting in a slight (1.1% to 1.3%) improvement in photovoltaic conversion efficiency compared to undoped TiO2. Such control of electron transport within the photoelectrode is attributed to improvements in electron injection through ICT transitions.

Enhanced charge separation and interfacial charge transfer of InGaN nanorods/C3N4 heterojunction photoanode

2019 ◽  
Vol 324 ◽  
pp. 134844 ◽  
Author(s):  
Zhenzhu Xu ◽  
Shuguang Zhang ◽  
Fangliang Gao ◽  
Peng Gao ◽  
Yuefeng Yu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Separation ◽  
Interfacial Charge Transfer ◽  
Interfacial Charge

Charge Carrier Transfer in Ta3N5 Photoanodes Prepared by Different Methods for Solar Water Splitting

2016 ◽  
Vol 69 (6) ◽  
pp. 631 ◽  
Author(s):  
Mingxue Li ◽  
Wenjun Luo ◽  
Liheng Yang ◽  
Xin Zhao ◽  
Zhigang Zou
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Water Splitting ◽  
Charge Separation ◽  
Preparation Method ◽  
Separation Efficiency ◽  
Interfacial Charge Transfer ◽  
Splitting Property ◽  
Charge Separation Efficiency ◽  
Interfacial Charge

The preparation method of a photoanode can affect its water splitting property. Here, as examples, we prepared Ta3N5 photoanodes by an electrophoresis deposition (EPD) method and an oxidation and nitridation of Ta foil (ONTF) method. The light harvest, interfacial charge transfer, and charge separation of the two Ta3N5 photoanodes were analysed to gain insight into the role of the preparation method on the water splitting property. The results suggested that the ONTF-prepared Ta3N5 showed a higher solar energy conversion efficiency, arising from its better interfacial charge transfer efficiency and higher charge separation efficiency. The higher charge separation efficiency was mainly attributed to good electron transfer, and the inter-particle connectivity was key for the electron transfer in the photoanodes. Especially, the dense, small particle structure of ONTF-prepared Ta3N5 was beneficial for increasing the connectivity between inter-particles. This comparison of preparation methods can be used as a reference for future photoanode preparation to improve the water splitting property of photoelectrochemical cells.

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