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The continuous search for low-cost and environment-friendly materials in photovoltaic applications has become a priority, as well as the understanding of the various strategies to boost the photovoltaic performance. In this work, we investigate the effect of TiCl _4 treatment on a compact TiO _2 layer used as an electron transport material (ETM) in Sb _2 S _3 planar solar cells. After TiCl _4 treatment, TiO _2 exhibits higher crystallinity, lower density of hydroxyl groups acting as traps, and better surface coverage of the FTO substrate. Although no major structural changes are observed in Sb _2 S _3 films grown on pristine or TiCl _4 treated TiO _2 films, there are differences in preferential growth of Sb _2 S _3 (hk1) planes, sulfur-enrichment of the chalcogenide film, and superior substrate coverage after the TiCl _4 treatment, leading to the decrease of interfacial trap states. The driving force for electron injection in the TiO _2 /Sb _2 S _3 heterojunction is also favored by the shift on the VB and CB positions of TiCl _4 treated TiO _2 . These findings are in agreement with the improved power conversion efficiency of the planar solar cell FTO/TiO _2-Treated /Sb _2 S _3 /SbCl _3 /spiro-OMeTAD/Au.

Fully printable carbon-based perovskite solar cells (C-PSCs) represent some of the most promising perovskite solar cell (PSC) architectures. Highly scalable, stable, and low in cost—these devices consist of a TiO2 compact layer (C-TiO2) and three sequentially screen-printed mesoporous layers of TiO2, ZrO2, and carbon, through which perovskite is infiltrated. While there has been remarkable progress in optimizing and scaling up deposition of mesoporous layers and perovskite, few publications have focused on optimizing C-TiO2. In this work, we investigate the potential for substituting commonly used spray pyrolysis with more easily scaled screen-printing. It was found that when comparing layers of similar thickness, 1 cm2 devices fabricated with printed C-TiO2 exhibited similar power conversion efficiency (PCE) to those fabricated with spray pyrolysis. In contrast, thicker-printed C-TiO2 led to lower efficiency. The influence of TiCl4 treatment on the quality of produced compact layers was also examined. This proved beneficial, mostly in the printed films, where a champion PCE of 13.11% was attained using screen-printed, TiCl4 treated C-TiO2. This work proves that screen-printing is a viable replacement for spray pyrolysis in C-PSCs fabrication. [ABSTRACT FROM AUTHOR]

Hybrid Li-ion capacitor (LIC) draws more attention as novel energy storage device owing to its high power density and high energy density. Designing three-dimensional electrode materials is beneficial for improving electrochemical performance of LICs. Herein, an improved hydrothermal method combined with an ion-exchange reaction is used to manufacture oxygen vacancies (OVs)-doping TiO 2 (TiO 2-x) nanowires/nanosheets (NWS) on Ti-foil. Then TiCl 4 treatment is performed to form TiO 2-x NWS/nanocrystallines (NWSC). These-obtained hierarchical nanoarchitectures assumes enrich electro-active sites and contact areas, which can improve electron transference and structural stability. The TiO 2-x NWSC is used as binder-free anode for Li-ion battery and achieves high specific capacity (300 mAh g−1 at 0.1 A g−1), excellent rate capability (102 mAh g−1 at 5 A g−1) and long cycle stability (44% after 1000 cycles at 1 A g−1). LICs assembled with a TiO 2-x NWSC anode and an activated carbon cathode have an energy density of 44.2 W h kg−1 at the power density of 150 W kg−1. Therefore, the TiO 2-x NWSC is a potential candidate for high energy and high power electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

Of the photoanode in QDSSC, the TiCl 4 solution treatment is widely used in mesoporous TiO 2 surface modification. However, device performance amplification and electron transfer capability improvement of the two common pre- or post treatment are seldom yet. In this work, we explore the TiCl 4 different treatments based on the typical TiO 2 nanowire array photoanode for CdS x Se 1-x QDSSC. In terms of the changes of electron transfer pathway, flat-band potential (V fb) and charge carrier concentration (N D), we explored the inducement and increase of electron transfer capability and efficacy under different treatments. As for the influence of device performance, the more negative V fb (−0.315 V, NHE) and higher N D (7.63 × 1019 cm−3) of PBS are beneficial to the increase of open-circuit voltage (V oc) and short-circuit current (J sc). Therefore, the TiCl 4 pre-treatment on photoanode modification (in PBS) is beneficial to reduce the resistances of charge transfer and recombination. The cell performance of PBS in CdS x Se 1-x QD sensitization was improved significantly: the PCE was 7.54%, the J sc was 18.93 mA/cm2, V oc was 0.78 V and fill factor (FF) was 51.1%. • TiCl 4 pre- or post-treatment achieves the self-doping of Ti3+ on TiO 2 photoanode. • PBS structure has a more negative V fb (−0.315 V, NHE) and higher N D (7.63 × 1019 cm−3). • The longer L D (0.93 μm) in PBS photoanode exhibits the higher electron transfer ability. • The PCE and J sc with pre-treated PBS photoanode increase higher to 7.54% and 18.93 mA/cm2. [ABSTRACT FROM AUTHOR]

Abstract Increasing the photocurrent is one of the main objectives of the current research on aqueous photovoltaic cells, the emerging green, alternative technology in solar energy conversion devices. In such a scenario, this work deals with the thorough understanding of the electrochemical and photoelectrochemical effects of the TiCl 4 treatment onto TiO 2 electrodes, a well-known process for traditional dye-sensitized solar cells, and here, to our knowledge, investigated for the first time in water-based systems. From the quantitative evaluation of the photoelectrochemical parameters, it emerges that the TiCl 4 treatment beneficially affects the photovoltaic parameters: it doubles the sunlight conversion efficiency values, inhibits the recombination of photogenerated electrons with oxidized redox mediator ions, and ensures stable and reproducible cell performance at the laboratory scale. Graphical abstract Image 1 Highlights • TiCl 4 treatment carried out to boost the efficiency of aqueous solar cells. • The treatment doubles the sunlight conversion efficiency values up to 2.5%. • Recombination of photogenerated electrons is strongly inhibited (OCVD/EIS study). • 100% water-based solar cells without additives or heavy metals. • Cells are very stable: +8% efficiency after 16 days of aging. [ABSTRACT FROM AUTHOR]

Abstract BaSnO 3 (BSO) could be becoming an important next generation electron transport material in semiconductor technology due to its abnormal electrical properties even at room temperature. In this study, the strontium (Sr) is doped into BSO semiconductor via the facile co-precipitation method and then used as electron transporter in dye sensitized solar cells (DSSCs) is reported towards improving the power conversion efficiency (PCE). The physiochemical properties changes in the BSO systems by Sr doping assisted for an expeditious photo charge carrier transportation by making a desirable conduction band edge alignment with neighbouring TiO 2 layer when use in BSO/TiCl 4 treatment/TiCl 4 scattering layer based photoanodes is confirmed by impedance studies. So, our new photoelectrode composition, 5% Sr: BSO/1 min TiCl 4 treatment/TiO 2 scattering layer yields one of the highest PCE by the outcome of 16.95 mA cm−2 (J sc), 0.63 (FF), and 0.82 V (V oc), which is 8.83%. This result shows superior PCE among all our early reports of photoanodes such as BSO, BSO/scattering layer, BSO/TiCl 4 treatment, BSO/TiCl 4 treatment/scattering layer and 3% Fe: BSO/TiCl 4 treatment/scattering layer. On the basis of recent reports, a gradual upsurge in the efficiency of BSO nanostructures based photoanodes under easily reproducible scientific/rational approach will facilitate an astonishing possibility to enhancing the PCE which confidently reinforce the probability of implementation in practical life and is indispensable for balancing the future non-renewable energy dearth. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Herein, we studied the effect of surface treatment of compact TiO2 layer by vacuum ultraviolet (VUV) light and by TiCl4 on the I- V hysteresis of perovskite solar cells prepared on fluorine-doped tin oxide (FTO) substrates with two different surface roughnesses. Initially, the cells prepared on flat FTO substrates show better results than cells prepared on rough FTO, with slightly higher power conversion efficiency (PCE) and less hysteresis in the I- V curves. Treatment of TiO2 prepared on flat FTO has no effect on the I- V hysteresis because of better contact between TiO2/CH3NH3PbI3 layers. Treatment of TiO2 layer on rough FTO has a positive effect on the PCE and I- V hysteresis and stability. [ABSTRACT FROM AUTHOR]

This paper reports the efficiency enhancement in dye-sensitized solar cells (DSSCs) by incorporation of silver nanoparticles (AgNPs) in Titanium dioxide (TiO2) and using it as anode. Further enhancement in DSSC parameters was observed after TiCl4treatment on TiO2Ag anode. It was observed that the short circuit current densityJscwas increased from 6.95 to 12.58 mA/cm2by TiCl4treatment with no change inVocand fill factor increasing the efficiency from 3.29 to 5.61%. The fabricated DSSCs using TiO2AgNPs anode with both pre and post TiCl4treatment appear to have the maximum efficiency as compared to other cells. Due to effective electron transport and enhanced absorption of dye on TiO2AgNPs anode surface, the maximum conversion efficiency of 7.3% was achieved. [ABSTRACT FROM PUBLISHER]

A highly photovoltaic performance of dye-sensitized solar cell with energy conversion efficiency about 9.20% is obtained through the addition of a blocking layer and TiCl4treatment on the TiO2film to suppress dark reaction. It is found that the addition of a 1.0-μm blocking layer in the photoelectrode can improve the energy conversion efficiency of a dye-sensitized solar cell from 7.41 to 7.92%, and the further 80°C TiCl4aqueous solution treatment on the TiO2film can also obviously enhance the energy conversion efficiency from 7.92 to 9.20%, due to the efficient suppression of dark reaction in the dye-sensitized solar cell. Thus, the addition of a blocking layer and TiCl4treatment on the TiO2film is an efficient way for fabricating highly photovoltaic performance of the dye-sensitized solar cell. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new and simple in-situ preparative method for CuS electrodes. [•] Suitable for different substrates. [•] TiCl4 pre-treatment to improve mechanical stabilities between CuS and substrates. [•] Improvement of CuS particles interconnection by TiCl4 post-treatment. [•] Up to 4.59% of efficiency is achieved. [ABSTRACT FROM AUTHOR]

An easy‐to‐implement strategy to introduce carbon nanohorns as interlayers in the photoelectrode of a dye‐sensitized solar cell without affecting its overall performance is presented. This provides a clean, easy, and ecofriendly alternative to achieve highly efficient cells. [ABSTRACT FROM AUTHOR]

ABSTRACT We have designed and fabricated dye solar cell (DSC) modules with optimized geometries and processes. Integrated interconnections were made following the 'Z' architecture for series connections. Several modules were prepared varying the materials, multilayer combination of the TiO2 active layers, and the fabrication processes. With the best combination of TiO2 multilayers, titanium tetrachloride (TiCl4) treatment, a back reflector/diffusor, and optimized layout of cells via simulations, we fabricated a DSC module with a conversion efficiency of 6.9% on 43 cm2 aperture area and 9.4% on active area. This result confirms that an effective scale-up of high performance Z-series-connected DSC modules can be achieved comparable with other thin film technology. Note that the materials used to produce the devices of this work are all commercially available: an important result for a technology that is being developed for industrial application. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: In order to prevent the charge recombination at the interface between the transparent-conducting oxide (TCO) substrate and electrolyte, a TiO2 compact layer was deposited on the substrate by hydrolysis of TiCl4 aqueous solution. Optimum thickness of the compact layer was found to be ∼25 nm, which showed ∼24% increase in the power-conversion efficiency compared with the bare cell. Impedance spectra indicated that the interfacial charge-transfer resistance of TCO/electrolyte interface was increased by more than a factor of three with the TiO2 compact layer at 0.4 V. Moreover, the electron-carrier lifetime of the 25 nm-deposited cell was improved by a factor of five compared with the bare cell. [Copyright &y& Elsevier]

Abstract: Titanium tetrachloride (TiCl4) treatment processed by chemical bath deposition is usually adopted as pre- and post-treatment for nanocrystalline titanium dioxide (TiO2) film deposition in the dye-sensitized solar cell (DSC) technology. Pre-treatment influences positively the bonding strength between the fluorinated tin oxide (FTO) substrate and the porous TiO2 layer, blocking the charge recombination at the interface between the conduction glass FTO and the I3 − ions present in the I−/I3 − red-ox couple. Additionally, TiCl4 post-treatment is a widely known method capable of improving the performance of dye-sensitized solar cells, in particular, the photocurrent collected from the device. In this study, the influence and effect of TiCl4 pre- and post-treatment on the TiO2 layer is proposed and compared to the untreated film. The relative DSC devices are characterized in terms of short circuit current density, open circuit voltage, fill factor, conversion efficiency and IPCE. The dark current characteristics of cells with a treated and untreated TiO2 layer are also shown in order to evaluate the effect of TiCl4 pre-treatment as a blocking layer. [Copyright &y& Elsevier]

Abstract: Photocurrents due to water oxidation at BiZn2VO6 (E g 2.4eV) particulate thin film electrodes were largely enhanced by pre-treatment with an aqueous TiCl4 solution. Photocurrents for BiZn2VO6 electrodes with no TiCl4 treatment were also enhanced by the addition of organic compounds such as methanol and trimethyl amine to the aqueous electrolyte. Interestingly, such enhanced photocurrents by organic compounds were further enhanced by the TiCl4 pre-treatment. EDAX and SEM investigations showed the formation of a flock-like TiO2 overlayer on BiZn2VO6 particles after the TiCl4 treatment. The photocurrent enhancement by the TiCl4 pre-treatment is thus mainly attributed to the necking effect of the flock-like TiO2 overlayer, which facilitates the transport of photogenerated electrons within the BiZn2VO6 particulate thin film electrode. [Copyright &y& Elsevier]

Abstract: In the present work, we produce 15μm thick titania mesosponge layers (TMSL) by a Ti anodization/etching process and use the layers in dye-sensitized solar cells (DSCs). We show that the solar cell efficiency can considerably be improved by a TiCl4 hydrolysis treatment (increase of approx. 40% to an overall value of 4.9% under AM 1.5 illumination). This beneficial effect is due to the decoration of the ∼10nm wide channels present in TMSL with TiO2 nanoparticles of approx. 3nm diameter, which allow for a significantly higher specific dye loading of the TMS structure. [Copyright &y& Elsevier]

Abstract: In the present work we investigate the effect of TiCl4 treatments on the photoconversion efficiency of TiO2 arrays used in dye sensitized solar cell. The results clearly show that by an appropriate treatment the decoration of the TiO2 nanotube arrays with TiO2 nanocrystallites of a typical size of 3nm can be achieved. These particles can be converted to mixture of anatase and rutile phase by annealing in air. This decoration of the TiO2 nanotubes leads to a significantly higher specific dye loading and, for certain annealing treatments, to a doubling of the solar cell efficiency (in our case from 1.9% to 3.8% of AM 1.5 conditions) can be achieved. [Copyright &y& Elsevier]

Abstract: Techniques of TiO2 film fabrication for dye-sensitized solar cells having a conversion efficiency of global air mass 1.5 (AM 1.5, 1000 W/m2) solar light to electric power over 10% are reported. Newly implemented fabrication technologies consist of pre-treatment of the working photoelectrode by TiCl4, variations in layer thickness of the transparent nanocrystalline-TiO2 and applying a topcoat light-scattering layer as well as the adhesion of an anti-reflecting film to the electrode''s surface. TiCl4 treatments induce improvements in the adhesion and mechanical strength of the nanocrystalline TiO2 layer. Optimization of the thickness of the TiO2 layer, acting as the working electrode, affects both the photocurrent and the photovoltage of the devices. Covering of the TiO2 photoanode by an anti-reflecting film results in enhancement of the photocurrent. Each of these components of film fabrication exerts a significant influence on the overall photovoltaic parameters of the devices resulting in improvements in the net energy conversion performance. [Copyright &y& Elsevier]

Evaluating and controlling the distribution of framework Al species in ZSM-5 zeolite, which consists of an orthorhombic MFI framework with 12 tetrahedral sites, are key issues for improving the acid-catalytic properties. The vapor-phase TiCl 4 treatment of ZSM-5 at 600 °C led to a drastic change in the framework Al distribution, as confirmed by 27Al magic-angle spinning nuclear magnetic resonance measurements and density functional theory calculations. The maximum of the 27Al NMR peak attributed to framework Al shifted drastically from 55 to 52 ppm following TiCl 4 treatment, suggesting that this treatment leads to selective dealumination of the framework Al species corresponding to the peak at 55 ppm. Ti-modified ZSM-5 showed moderate acidity in catalytic reactions such as the ethylene-to-propylene reaction and various cracking reactions. It is suggested that TiCl 4 treatment results in the selective release of strong Brønsted acid sites from the MFI framework. Thus, the proposed post-synthetic treatment method provides an effective approach for tuning the catalyti c properties of ZSM-5 zeolite. Image 1 • Vapor-phase TiCl 4 treatment of ZSM-5 at 600 °C led to a drastic change in the distribution of framework Al. • TiCl 4 treatment causes selective dealumination of framework Al corresponding to 55 ppm within the MFI framework. • Selective release of strong Brønsted acid sites of ZSM-5 zeolite catalyst occurs during TiCl 4 treatment. [ABSTRACT FROM AUTHOR]

Perovskite solar cells have gained increasing interest in recent times owing to the rapidly enlarged device efficiency and tunable optoelectronic properties in various applications. In perovskite solar cells, interface engineering plays an important role in determining the final device efficiency and stability. In this study, we adopted TiCl4 treatment to reduce the surface roughness of the metal oxide layer and improve the perovskite film quality to obtain better device performance. After proper TiCl4 treatment, the efficiencies of TiCl4–TiO2- and TiCl4–ZnO-based devices were significantly enhanced up to 16.5% and 17.0%, respectively, compared with those based on pristine TiO2 and ZnO (13.2% and 10.2%, respectively). [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) without a mesoporous TiO 2 layer, that is, planar-type PSCs exhibit poorer cell performance as compared to PSCs with a porous TiO 2 layer, owing to inefficient electron transfer from the perovskite layer to the compact TiO 2 layer in the former case. The matching of the conduction band levels of perovskite and the compact TiO 2 layer is thus essential for enhancing PSC performance. In this study, we demonstrate the shifting of the conduction band edge (CBE) of the compact TiO 2 layer through a TiCl 4 treatment, with the aim of improving PSC performance. The CBE of the compact TiO 2 layer was shifted to a higher level through the TiCl 4 treatment and then shifted in the opposite direction, that is, to a lower level, through a subsequent heat treatment. These shifts in the CBE were reflected in the PSC performance. The TiCl 4 -treated PSC showed an increase in the open-circuit voltage of more than 150 mV, as well as a decrease of 100 mV after being heated at 450 °C. On the other hand, the short-circuit current decreased after the treatment but increased after heating at temperatures higher than 300 °C. The treated PSC subjected to subsequent heating at 300 °C exhibited the best performance, with the power conversion efficiency of the PSC being 17% under optimized conditions.