Alkyl-Group-Wrapped Unsymmetrical Squaraine Dyes for Dye-Sensitized Solar Cells: Branched Alkyl Chains Modulate the Aggregation of Dyes and Charge Recombination Processes

2019 ◽  
Vol 12 (2) ◽  
pp. 2555-2565 ◽  
Author(s):  
Ambarish Kumar Singh ◽  
Munavvar Fairoos Mele Kavungathodi ◽  
Jayaraj Nithyanandhan
2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Reda M. El-Shishtawy ◽  
Shaaban A. Elroby ◽  
Abdullah M. Asiri ◽  
Rifaat H. Hilal

In an effort to provide, assess, and evaluate a theoretical approach which enables designing efficient donor-acceptor dye systems, the electronic structure and optical properties of pyran-squaraine as donor-acceptor dyes used in dye-sensitized solar cells were investigated. Ground state properties have been computed at the B3LYP/6-31+G**level of theory. The long-range corrected density functionals CAM-B3LYP, PBEPBE, PBE1PBE (PBE0), and TPSSH with 6-311++G**were employed to examine absorption properties of the studied dyes. In an extensive comparison between experimental results and ab initio benchmark calculations, the TPSSH functional with 6-311++G**basis set was found to be the most appropriate in describing the electronic properties for the studied pyran and squaraine dyes. Natural transition orbitals (NTO), frontier molecular orbitals (FMO), LUMO, HOMO, and energy gaps, of these dyes, have been analyzed to show their effect on the process of electron injection and dye regeneration. Interaction between HOMO and LUMO of pyran and squaraine dyes was investigated to understand the recombination process and charge-transfer process involving these dyes. Additionally, we performed natural bond orbital (NBO) analysis to investigate the role of charge delocalization and hyperconjugative interactions in the stability of the molecule.


2012 ◽  
Vol 125 (3) ◽  
pp. 1007-1009 ◽  
Author(s):  
Emanuele Maggio ◽  
Natalia Martsinovich ◽  
Alessandro Troisi

RSC Advances ◽  
2017 ◽  
Vol 7 (67) ◽  
pp. 42013-42023 ◽  
Author(s):  
Ting-Kuang Chang ◽  
Yun Chi

The sensitizer TF-tBu_C3F7 has shown the highest overall efficiencies of JSC = 18.47 mA cm−2, VOC = 767 mV, FF = 0.71 and PCE = 10.05% under simulated one sun irradiation, due to the fine balance between dye loading and reduced charge recombination.


RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84959-84966 ◽  
Author(s):  
Dong-Li Gao ◽  
Yi Wang ◽  
Ping Zhang ◽  
Li-Min Fu ◽  
Xi-Cheng Ai ◽  
...  

Charge recombination takes place, respectively, within the frameworks of transfer- and transport-limited recombination mechanisms, at low and high electron density.


2018 ◽  
Vol 10 (31) ◽  
pp. 26335-26347 ◽  
Author(s):  
Rajesh Bisht ◽  
Vediappan Sudhakar ◽  
Munavvar Fairoos Mele Kavungathodi ◽  
Neeta Karjule ◽  
Jayaraj Nithyanandhan

Author(s):  
Suping Jia ◽  
Tong Cheng ◽  
Huinian Zhang ◽  
Hao Wang ◽  
Caihong Hao

Defect states in the TiO2 nanoparticles can cause severe charge recombination and poor electron-transport efficiency when used as a photoanode in dye-sensitized solar cells (DSSCs). Herein, we report a simple and practical way to passivate the surface defects of TiO2 through hydrothermal treating with acetic acid and H2SO4, introducing a high percentage of 101 facets and sulfonic acid functional groups on the TiO2 surface. A high efficiency of 8.12% has been achieved, which is 14% higher than that of untreated TiO2 under the same condition. EIS results prove that the multiacid-treated TiO2 can promote electron transport and reduce charge recombination at the interface of the TiO2 and electrolyte. This work provides an efficient approach to engineer the electron-transport pathway in DSSCs.


Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1645 ◽  
Author(s):  
Seong Il Cho ◽  
Hye Kyeong Sung ◽  
Sang-Ju Lee ◽  
Wook Hyun Kim ◽  
Dae-Hwan Kim ◽  
...  

At an elevated temperature of 90 °C, a chemical bath deposition using an aqueous solution of Zn(NO3)2·6H2O and (CH2)6N4 resulted in the formation of both nanoflowers and microrods of ZnO on F-doped SnO2 glass with a seed layer. The nanoflowers and microrods were sensitized with dyes for application to the photoelectrodes of dye-sensitized solar cells (DSSCs). By extending the growth time of ZnO, the formation of nanoflowers was reduced and the formation of microrods favored. As the growth time was increased from 4 to 6 and then to 8 h, the open circuit voltage (Voc) values of the DSSCs were increased, whilst the short circuit current (Jsc) values varied only slightly. Changes in the dye-loading amount, dark current, and electrochemical impedance were monitored and they revealed that the increase in Voc was found to be due to a retardation of the charge recombination between photoinjected electrons and I3− ions and resulted from a reduction in the surface area of ZnO microrods. A reduced surface area decreased the dye contents adsorbed on the ZnO microrods, and thereby decreased the light harvesting efficiency (LHE). An increase in the electron collection efficiency attributed to the suppressed charge recombination counteracted the decreased LHE, resulting in comparable Jsc values regardless of the growth time.


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