Solar cells with PbS quantum dot sensitized TiO₂–multiwalled carbon nanotube composites, sulfide-titania gel and tin sulfide coated C-fabric

Abstract

Novel approaches to boost quantum dot solar cell (QDSC) efficiencies are in demand. Herein, three strategies are used: (i) a hydrothermally synthesized TiO-multiwalled carbon nanotube (MWCNT) composite instead of conventional TiO, (ii) a counter electrode (CE) that has not been applied to QDSCs until now, namely, tin sulfide (SnS) nanoparticles (NPs) coated over a conductive carbon (C)-fabric, and (iii) a quasi-solid-state gel electrolyte composed of S, an inert polymer and TiO nanoparticles as opposed to a polysulfide solution based hole transport layer. MWCNTs by virtue of their high electrical conductivity and suitably positioned Fermi level (below the conduction bands of TiO and PbS) allow fast photogenerated electron injection into the external circuit, and this is confirmed by a higher efficiency of 6.3% achieved for a TiO-MWCNT/PbS/ZnS based (champion) cell, compared to the corresponding TiO/PbS/ZnS based cell (4.45%). Nanoscale current map analysis of TiO and TiO-MWCNTs reveals the presence of narrowly spaced highly conducting domains in the latter, which equips it with an average current carrying capability greater by a few orders of magnitude. Electron transport and recombination resistances are lower and higher respectively for the TiO-MWCNT/PbS/ZnS cell relative to the TiO/PbS/ZnS cell, thus leading to a high performance cell. The efficacy of SnS/C-fabric as a CE is confirmed from the higher efficiency achieved in cells with this CE compared to the C-fabric based cells. Lower charge transfer and diffusional resistances, slower photovoltage decay, high electrical conductance and lower redox potential impart high catalytic activity to the SnS/C-fabric assembly for sulfide reduction and thus endow the TiO-MWCNT/PbS/ZnS cell with a high open circuit voltage (0.9 V) and a large short circuit current density (∼20 mA cm). This study attempts to unravel how simple strategies can amplify QDSC performances.

Mechanical, Thermal and Morphological Characterisation of Polybutylene based Composites

“…It is known that many polymers wear more in water than in air 7-9. Watanabe et al [44]. Wear of PTFE compounds with 10-12 glass fibers only Found to be filled.…”

Functionalized Thermoplastic Polyurethane Gel Electrolytes for Cosensitized TiO2/CdS/CdSe Photoanode Solar Cells with High Efficiency

“…The most common liquid electrolytes used in QDSSCs are I – /I 3 – and S 2– /S n 2– . The solar cells using liquid electrolytes suffer from leakage, easily vaporize, are difficult to handle, and exhibit performance instability, and these electrolytes also corrode the working electrode in QDSSCs. , Further, the use of liquid electrolytes in QDSSCs faces challenge for sealing and long-term stability and, therefore, raise a need to develop solid electrolytes . A number of solid-state polymer electrolytes and quasisolid (gel) polymer electrolytes were used in QDSSCs, but the gel polymer electrolytes performed better than the solid polymer electrolytes in terms of their ionic conductivity and transport ability .…”

“…Inorganic semiconductors (QDs) are used as light-absorbing materials instead of organic dyes in solar cells to generate excitons, which are known as QD-sensitized solar cells (QDSSCs). QDs are used as sensitizers because of their tunable band gap through quantum confinement effect (modifying the band gap by changing the size of QDs) 6 and high excitation coefficient which reduces the dark current, resulting in the increase of solar cell efficiency. 7 In semiconductor devices, the electrons and holes are exposed simultaneously to different forces and both of them are important for solar cell operation; one is the electric force, and the other generalized force is related to the gradient of their concentration.…”

Photocatalysis and UV-blocking properties of cotton fabric functionalized with BiPO4nanorods

“…As one of the most typical photocatalysts, TiO 2 -based materials can efficiently oxidize pollutants, such as toxic and dye waste water into CO 2 and H 2 O. [6][7][8][9] Because of the high recombination of photo-induced electron-hole pairs and low utilization of visible light, TiO 2based materials still have a lot of problems in actual 10 applications. Developing new type of photocatalysts with high photocatalytic activity is an effective solution to the problem.…”