Stability, Scale-up and Performance of Quantum Dot Solar Cells with Carbonate Treated Titanium Oxide Films

Kumar, P N and Kolay, A and Melepurath, D and Shivaprasad, S M and Srivastava, A K (2017) Stability, Scale-up and Performance of Quantum Dot Solar Cells with Carbonate Treated Titanium Oxide Films. ACS Applied Materials and Interfaces. ISSN 1944-8244 (In Press)

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Abstract

A novel yet simple approach of carbonate (CBN) treatment of TiO2 films is performed, and quantum dot solar cells (QDSCs) with high power conversion efficiencies (PCEs), reasonably good stabilities, and good fill factors (FFs) are fabricated with TiO2-CBN films. The ability of carbonate groups to passivate defects or oxygen vacancies of TiO2 is confirmed from a nominally enhanced band gap, a lowered defect induced fluorescence intensity, an additional Ti-OH signal obtained after carbonate decomposition, and a more capacitive low frequency electrochemical impedance behavior achieved for TiO2-CBN compared to untreated TiO2. A large area QDSC of 1 cm2 with a TiO2-CBN/CdS/Au@PAA (poly(acrylic acid)) photoanode delivers an enhanced PCE of 4.32% as opposed to 3.03% achieved for its’ analogous cell with untreated TiO2. Impedance analysis illustrates the role of carbonate treatment in increasing the recombination resistance at the photoanode/electrolyte interfaces, and in suppressing back electron transfer to the electrolyte, thus validating the superior PCE achieved for the cell with carbonate treated TiO2. QDSCs with the following configuration: TiO2-CBN/CdS/Au@PAA-polysulfide/SiO2 gel-Carbon-fabric/WO3-x and active areas of 0.2-0.3 cm2, yield efficiencies in the range of 5.16 to 6.3% and the average efficiency of the cells is 5.9%. The champion cell is characterized by the following photovoltaic parameters: JSC (short circuit current density): 11.04 mA cm-2, VOC (open circuit voltage): 0.9 V, FF: 0.63 and PCE: 6.3%. Stability tests performed on this cell show that dark storage has a less deleterious effect on cell performance compared to extended illumina-tion. In dark, the PCE of the cell dropped from 5.69 to 5.52%, and under prolonged continuous irradiance of 5 h, it decreased from 5.91 to 4.83%. A scaled-up QDSC with the same architecture of 4 cm2 size showed a PCE of 1.06%, and the demonstration of the lighting of a LED accomplished using this cell, exemplifies that this cell can be used for powering electronic devices that require low power.

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IITH Creators:
IITH CreatorsORCiD
Melepurath, DUNSPECIFIED
Item Type: Article
Subjects: Chemistry
Divisions: Department of Chemistry
Depositing User: Team Library
Date Deposited: 17 Jul 2017 09:40
Last Modified: 17 Jul 2017 09:40
URI: http://raiith.iith.ac.in/id/eprint/3394
Publisher URL: https://doi.org/10.1021/acsami.7b05726
OA policy: http://www.sherpa.ac.uk/romeo/issn/1944-8244/
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