Lithium metal anodes have attracted extensive attention owing to their high theoretical specific capacity. However, the notorious reactivity of lithium prevents their practical applications, as ...evidenced by the undesired lithium dendrite growth and unstable solid electrolyte interphase formation. Here, we develop a facile, cost-effective and one-step approach to create an artificial lithium metal/electrolyte interphase by treating the lithium anode with a tin-containing electrolyte. As a result, an artificial solid electrolyte interphase composed of lithium fluoride, tin, and the tin-lithium alloy is formed, which not only ensures fast lithium-ion diffusion and suppresses lithium dendrite growth but also brings a synergistic effect of storing lithium via a reversible tin-lithium alloy formation and enabling lithium plating underneath it. With such an artificial solid electrolyte interphase, lithium symmetrical cells show outstanding plating/stripping cycles, and the full cell exhibits remarkably better cycling stability and capacity retention as well as capacity utilization at high rates compared to bare lithium.
Traditional chemical, physical and biological processes for treating wastewater containing textile dye have such disadvantages as high cost, high energy requirement and generation of secondary ...pollution during treatment process. The advanced oxidation processes technology has been attracting growing attention for the decomposition of organic dyes. Such processes are based on the light-enhanced generation of highly reactive hydroxyl radicals, which oxidize the organic matter in solution and convert it completely into water, CO
2
and inorganic compounds. In this presentation, the photocatalytic degradation of dyes in aqueous solution using TiO
2
as photocatalyst under solar and UV irradiation has been reviewed. It is observed that the degradation of dyes depends on several parameters such as pH, catalyst concentration, substrate concentration and the presence of oxidants. Reaction temperature and the intensity of light also affect the degradation of dyes. Particle size, BET-surface area and different mineral forms of TiO
2
also have influence on the degradation rate.
Interface engineering is critical to the development of highly efficient perovskite solar cells. Here, urea treatment of hole transport layer (e.g., poly(3,4‐ethylene dioxythiophene):polystyrene ...sulfonate (PEDOT:PSS)) is reported to effectively tune its morphology, conductivity, and work function for improving the efficiency and stability of inverted MAPbI3 perovskite solar cells (PSCs). This treatment has significantly increased MAPbI3 photovoltaic performance to 18.8% for the urea treated PEDOT:PSS PSCs from 14.4% for pristine PEDOT:PSS devices. The use of urea controls phase separation between PEDOT and PSS segments, leading to the formation of a unique fiber‐shaped PEDOT:PSS film morphology with well‐organized charge transport pathways for improved conductivity from 0.2 S cm−1 for pristine PEDOT:PSS to 12.75 S cm−1 for 5 wt% urea treated PEDOT:PSS. The urea‐treatment also addresses a general challenge associated with the acidic nature of PEDOT:PSS, leading to a much improved ambient stability of PSCs. In addition, the device hysteresis is significantly minimized by optimizing the urea content in the treatment.
Here, urea treatment of hole transport layer (e.g., poly(3,4‐ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS)) is reported to effectively tune its morphology, conductivity, and work function for improving the efficiency and stability of inverted CH3NH3PbI3 perovskite solar cells.
In recent years, hybrid perovskite solar cells (HPSCs) have received considerable research attention due to their impressive photovoltaic performance and low‐temperature solution processing ...capability. However, there remain challenges related to defect passivation and enhancing the charge carrier dynamics of the perovskites, to further increase the power conversion efficiency of HPSCs. In this work, the use of a novel material, phenylhydrazinium iodide (PHAI), as an additive in MAPbI3 perovskite for defect minimization and enhancement of the charge carrier dynamics of inverted HPSCs is reported. Incorporation of the PHAI in perovskite precursor solution facilitates controlled crystallization, higher carrier lifetime, as well as less recombination. In addition, PHAI additive treated HPSCs exhibit lower density of filled trap states (1010 cm−2) in perovskite grain boundaries, higher charge carrier mobility (≈11 × 10−4 cm2 V−1 s), and enhanced power conversion efficiency (≈18%) that corresponds to a ≈20% improvement in comparison to the pristine devices.
A novel material called phenylhydrazinium iodide (PHAI) is effective for defects minimization, surface passivation, and efficient charge transportation in hybrid perovskite solar cells. It plays multiple roles in controlled crystallization, stabilizing under‐coordinated ions, and as a self‐supported moisture barrier in perovskite films.
Lithium metal anodes are expected to drive practical applications that require high energy‐density storage. However, the direct use of metallic lithium causes safety concerns, low rate capabilities, ...and poor cycling performance due to unstable solid electrolyte interphase (SEI) and undesired lithium dendrite growth. To address these issues, a radio frequency sputtered graphite‐SiO2 ultrathin bilayer on a Li metal chips is demonstrated, for the first time, as an effective SEI layer. This leads to a dendrite free uniform Li deposition to achieve a stable voltage profile and outstanding long hours plating/stripping compared to the bare Li. Compared to a bare Li anode, the graphite‐SiO2 bilayer modified Li anode coupled with lithium nickel cobalt manganese oxide cathode (NMC111) and lithium titanate shows improved capacity retention, higher capacity at higher rates, longer cycling stability, and lower voltage hysteresis. Graphite acts as an electrical bridge between the plated Li and Li electrode, which lowers the impedance and buffers the volume expansion during Li plating/stripping. Adding an ultrathin SiO2 layer facilitates Li‐ion diffusion and lithiation/delithiation, provides higher electrolyte affinity, higher chemical stability, and higher Young's modulus to suppress the Li dendrite growth.
The radio frequency sputtered graphite–SiO2 ultrathin bilayer on a Li metal chips is demonstrated to be an effective solid‐electrolyte interface layer. The graphite and SiO2‐sputtered Li anode leads to a dendrite‐free uniform Li deposition, lower voltage hysteresis, higher capacity at higher rates, high capacity retention, and longer cycling stability.
This focused review attempts to capture and collate some of the key advancements achieved on two vital components: charge transport (hole/electron) layers and contact electrodes in flexible ...perovskite photovoltaics.
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Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity. The beneficial and unique optoelectronic characteristics of perovskite structures enable researchers to achieve an incredibly remarkable power conversion efficiency. Flexible hybrid perovskite photovoltaics promise emerging applications in a myriad of optoelectronic and wearable/portable device applications owing to their inherent intriguing physicochemical and photophysical properties which enabled researchers to take forward advanced research in this growing field. Flexible perovskite photovoltaics have attracted significant attention owing to their fascinating material properties with combined merits of high efficiency, light-weight, flexibility, semi-transparency, compatibility towards roll-to-roll printing, and large-area mass-scale production. Flexible perovskite-based solar cells comprise of 4 key components that include a flexible substrate, semi-transparent bottom contact electrode, perovskite (light absorber layer) and charge transport (electron/hole) layers and top (usually metal) electrode. Among these components, interfacial layers and contact electrodes play a pivotal role in influencing the overall photovoltaic performance. In this comprehensive review article, we focus on the current developments and latest progress achieved in perovskite photovoltaics concerning the charge selective transport layers/electrodes toward the fabrication of highly stable, efficient flexible devices. As a concluding remark, we briefly summarize the highlights of the review article and make recommendations for future outlook and investigation with perspectives on the perovskite-based optoelectronic functional devices that can be potentially utilized in smart wearable and portable devices.
Photovoltaic power‐conversion systems can harvest energy from sunlight almost perpetually whenever sunrays are accessible. Meanwhile, as indispensable energy storage units used in advanced ...technologies such as portable electronics, electric vehicles, and renewable/smart grids, batteries are energy‐limited closed systems and require constant recharging. Fusing these two essential technologies into a single device would create a sustainable power source. Here, it is demonstrated that such an integrated device can be realized by fusing a rear‐illuminated single‐junction perovskite solar cell with Li4Ti5O12‐LiCoO2 Li‐ion batteries, whose photocharging is enabled by an electronic converter via voltage matching. This design facilitates a straightforward monolithic stacking of the battery on the solar cell using a common metal substrate, which provides a robust mechanical isolation between the two systems while simultaneously providing an efficient electrical interconnection. This system delivers a high overall photoelectric conversion‐storage efficiency of 7.3%, outperforming previous efforts on stackable integrated architectures with organic–inorganic photovoltaics. Furthermore, converter electronics facilitates system control with battery management and maximum power point tracking, which are inevitable for efficient, safe, and reliable operation of practical loads. This work presents a significant advancement toward integrated photorechargeable energy storage systems as next‐generation power sources.
A simple yet efficient hybrid photorechargeable design is presented, which consists of a monolithic integration of perovskite solar cell and lithium ion battery enabled by an electronic converter and demonstrates an overall photoelectric conversion‐storage efficiency of 7.3%.
In this work, oxygen vacancies were created to activate tungsten trioxide (WO3) as a highly efficient counter electrode (CE) in dye-sensitized solar cells (DSSCs). The levels of oxygen vacancies ...(OVs) in WO3 were finely formed and tuned by doping with different weight percentages (3, 5, and 9 wt%) of urea and annealing in a N2 environment at 470 °C. The urea doped WO3 significantly improved the electrocatalytic behaviour in the iodide–triiodide electrolyte. The effects of OVs on the catalytic performance of WO3 CEs were fully studied and understood. This improvement was attributed to the introduction of OVs into WO3, which acted as surface shallow states to facilitate electron transfer from the WO3 counter electrode to the electrolyte. At a high temperature of 470 °C, urea decomposes into the reactive H2 gas that can remove oxygen atoms from the WO3 surface and create OVs. 5 wt% urea was found to be the optimal urea concentration that led to the highest catalytic performance as evidenced by the cyclic voltammetry measurements. The 5 wt% urea doped WO3 CE-based device achieved a power conversion efficiency (PCE) of ∼10.5%, which was improved from the reference Pt CE-based device at ∼9.3% and non-active WO3 CE based cell at 3.32%. This has led to the optimal number of OVs that facilitate the charge transfer at the CE/electrolyte interface.
Herein, we clearly demonstrate that the inclusion of the organic solid additive (2,3-dihydroxypyridine, DOH) into the poly(diketopyrrolopyrrole-terthiophene) (PDPP3T) and phenyl-C61-butyric acid ...methyl ester (PCBM) (PDPP3T:PCBM) photoactive blend system alters the nanoscale morphology and enhances the photovoltaic (PV) performance of the inverted bulk heterojunction (BHJ) based polymer solar cells (PSCs). The influence of DOH additive casted PDPP3T: PCBM thin films on the optical, morphology and structural features is evaluated and correlated with PV characteristics. Topography images through atomic force microscopy reveal that the incorporation of DOH into PDPP3T: PCBM induces a finer nanoscale phase segregation between polymer and fullerene domains with fibrillar morphology. The PV performance of the DOH processed PDPP3T: PCBM devices is evaluated by current-voltage (J-V) characteristics and compared with pristine and 1, 8-diiodooctane (DIO) modified PDPP3T: PCBM devices. Interestingly, the incorporation of DOH (0.5 wt%) into PDPP3T: PCBM device witnessed the best PCE of 6.36%, which is significantly higher (69.1%) than that of the reference (3.76%). This significant enhancement in the performance of the device is mainly attributed to a dramatic increase in the short-circuit current density and fill-factor due to the improved bicontinuous interpenetrated phase separation and balanced charge transport. In addition, the measurements on photo-induced charge carrier extraction by linearly increasing voltage reveal that DOH incorporated devices exhibit higher mobility and charge carrier density as compared to those of pristine modified BHJ PSCs. The presence of vicinal functional groups in DOH contributes to the possible molecular level interactions with the blend components and accounts for the morphology and device performance enhancements.
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•The inclusion of the functional solid additive, 2,3-dihydroxypyridine (DOH) significantly (69.1%) enhanced the efficiency.•DOH has two vicinal hydroxyl groups for augmenting the molecular level interactions with photoactive blend components.•Systematically evaluated the influence of DOH through morphology, optoelectronic and film/device characterizations.•The nanomorphology modifications by DOH contribute as the major factor for the enhancement of photovoltaic performance.•The molecular structures of the DOH and components play pivotal role on the morphology and device performance enhancements.
The efficiencies of perovskite solar cells have been significantly increased to 18%, 17.01% and 15.6% for the cells containing the additives BMImI, LiI and LiTFSI in the PbI2 precursor solutions, ...respectively, from 11.3% for the devices without any additives. Incorporation of these additives led to the formation of perovskites with larger grain size and higher crystallinity with reduced PbI2 residue as indicated by X-ray diffraction (XRD) and atomic force microscopy (AFM) results. Kelvin Probe Force Microscopy (KPFM) and current sensing (CS)-AFM results were in good agreement with external quantum efficiency (EQE) measurements and proved the great enhancement in short circuit current density (Jsc) as a result of doping. Transient photovoltage measurement results exhibited longer charge carrier lifetimes for the additive incorporated perovskites than those without additives, thus improving the fill factor (FF) and open circuit voltage (Voc). In addition to the improved efficiency, the incorporation of these additives led to higher stability of the CH3NH3PbI3 perovskite solar cells. The new additive BMImI, LiI and LiTFSI incorporated CH3NH3PbI3 perovskite solar cells exhibited a reduced degradation with a 57%, 60%, and 91% decrease in performance respectively after exposure to air for 70 days compared to a 93% decrease for the pristine cell after only 24 days. The lithium salt additives can serve as desiccants to absorb moisture preventing perovskite degradation. Further, the BMImI additive can prevent the formation of free radicals in perovskites upon exposure to light and heat.
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