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![Figure 2-25 represents these quantized vibrations. [59]](profile/Mohsen-Shahshahan/publication/348232742/figure/fig17/AS:976565705908251@1609842816980/25-represents-these-quantized-vibrations-59_Q320.jpg)
Carbon nanotubes (CNTs) due to their unique properties are used in the various applications. Oftentimes for using this material as a component of a composite material, uniform dispersion of CNTs particles plays vital role in the final properties of structure. Ultrasonication technique is one of the major methods for dispersion of carbon nanotubes i...
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... According to Figure However, the current density is limited by the weaker electrode. [2] So based on what was discussed, current research tries to design new copper-based oxide semiconductors as (19) PCE is defined by: ...
... 19).[24] ...
... 19: Relationship between average particles size of semiconductors and P1 dye adsorption capability of the semiconductors. ...
The first reported dye-sensitized solar cells (DSSCs) known as photoanode dye-sensitized solar cells (n-DSSCs) or Grätzel cells operate via exciting dye electrons and electron injection through an n-type semiconductor (TiO2). The next generation of DSSCs including p-DSSC (photocathode DSSCs) and pn-DSSCs (tandem DSSCs) were designed to boost photovoltaic performance, efficiency and open circuit voltage (VOC) of DSSCs.
This thesis concerned a strategy to improve the open circuit voltage (VOC) of p-type dye-sensitized solar cells (p-DSSCs), with a focus on designing novel p-type semiconductors to use instead of NiO (as the most common and popular p-type semiconductor using in p-DSSCs and pn-DSSCs). To achieve this target, copper-based oxides (particularly those with delafossite structures) are attractive choice, because these semiconductors tend to provide reasonable transparency and hole mobility due to their own large band gap and specific orbital configuration of Cu+ respectively. In terms of getting higher VOC in p-DSSCs, a suitable valence band edge for semiconductor part can be considered as deep as possible, but not deeper than the HOMO level of sensitizer (dye), to create a driving force for charge transfer between a photoexcited dye and VB of semiconductor.
In order to narrow down the many possible candidate materials (CuMO2), the band structure computation of different semiconductors with CuMO2 (M: metallic element) structure was done based on density functional theory (DFT), and five semiconductors were synthesized. In order to semiconductor synthesis, CuMnO2 was synthesized via hydrothermal method; CuInO2 was obtained by ions exchange method; and Cu3Mn3O8, Cu2NiMn3O8, and CuO-NiO nanocomposite were synthesized by sol-gel approach. Also P1 and PMI-6T-TPA were used as sensitizers because of their suitable absorption range (matched with the wavelength range that radiation intensity of sunlight is maximum) in our p-DSSCs devices. And because they have been demonstrated in the literature to be good dyes for p-DSSCs.
The photovoltaic characterization measurements revealed that p-DSSC devices with [CuO-NiO nanocomposite + P1] and [Cu3Mn3O8 + P1] photocathode electrodes showed maximum VOC of 160 and 120 mV respectively, while for devices with [commercial NiO + P1] photocathode electrode, the highest recorded VOC was 110 mV.
On the other hand, PMI-6T-TPA improved photovoltaic performance of all p-DSSCs devices, where devices which their photocathode electrodes consisted commercial NiO along with this
dye showed maximum VOC of 330 mV. Using CuO-NiO nanocomposite and CuInO2 semiconductors instead of commercial NiO resulted in maximum VOC of 360 mV in these devices.
