Morphological and electron mobility studies in nanograss In2O3 DSSC incorporating multi-walled carbon nanotubes

Abstract

In 2 O 3 and In 2 O 3 -MWCNTs, thin films were prepared by means of sol-gel spin coating technique for dyesensitized solar cells (DSSCs). The morphological characteristics of In 2 O 3 and In 2 O 3 -MWCNT thin films were studied via atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The porous and rough surface structure of nanograss In 2 O 3 increased the surface area for improved dye loading. The low photovoltage issue in In 2 O 3 -based DSSCs was addressed by the incorporation of MWCNTs. The bandgap decreased when In 2 O 3 was incorporated with MWCNTs. The presence of MWCNTs in the thin film caused the fermi level (E F ) to shift upward and this leads to a larger energy gap between E F and the iodine redox level (E REDOX ) that results in higher photovoltage. The In 2 O 3 -MWCNT-based DSSCs exhibited better photovoltaic performance than In 2 O 3 -based DSSC with photovoltaic efficiency of 1.29 and 0.14 %, respectively. The electrochemical impedance spectroscopy (EIS unit) supported the photovoltaic performance by quantifying that the In 2 O 3 -MWCNT thin films provide more efficient charge transfer with the lowest effective recombination rate and high electron lifetime, hence improving the performance of DSSCs.

Ultrathin Niobate Nanosheet Assembly with Au NPs and CdS QDs as a Highly Efficient Photocatalyst

“…The semiconductors and Au NPs would establish a Schottky contact, and electrons would pass from the CB of CdS and HNb 3 O 8 to Au NPs. In the photocatalytic process, the Au NPs act as a cocatalyst (Figure 9 pathway 3) [36,53] …”

“…In the photocatalytic process, the Au NPs act as a cocatalyst (Figure 9 pathway 3). [36,53] Photocatalytic oxidative self-coupling of benzylamine is performed with the water circulation system to keep the temperature constant, and under air atmosphere for 10 h. The experimental results are listed in Table 1. Without light irradiation and blank runs give very few conversions for this 1, entry 4), which may be due to the small particle size and abundant catalytic active sites of quantum dots.…”

Au Nanoparticle and CdS Quantum Dot Codecoration of In2O3 Nanosheets for Improved H2 Evolution Resulting from Efficient Light Harvesting and Charge Transfer

“…At the In 2 O 3 –Au–CdS interface, the Fermi energy level of Au lies lower than that of CdS and In 2 O 3 . The Schottky contact will form between semiconductors and Au NPs, where the electrons jump from the CB of CdS and In 2 O 3 to Au NPs, and the Au NPs work as a cocatalyst in the generation of hydrogen (pathway II). ,,, At the In 2 O 3 –CdS–Au interface, In 2 O 3 , CdS, and Au have intimate contact with each other and form the three inner interfaces of In 2 O 3 –CdS, In 2 O 3 –Au, and CdS–Au where one type-I heterojunction and a couple of Schottky contacts exist at the same time; thus, the photogenerated electrons not only transfer from In 2 O 3 to CdS and Au but also transfer along the In 2 O 3 –Au and CdS–Au interfaces under the driving forces of the double inner electronic field resulting from the heterojunction and Schottky barrier, facilitating the separation of charge carriers (pathway III). Moreover, due to the SPR effect of noble metal, Au NPs absorb visible light to produce the photogenerated hot electrons, resulting in an improvement of charge carrier density. ,, The synergistic effects of the SPR effect, the heterojunction between semiconductor and semiconductor, and the Schottky barrier between semiconductor and noble metal facilitate the utilization of the light source and accelerate the generation and separation of electrons and holes, thus boosting the generation of H 2 .…”