Room-temperature Solution Process Research Articles

Room-temperature nanojoining of silver nanowires by graphene oxide for highly conductive flexible transparent electrodes

Flexible transparent electrodes for touch panels, solar cells, and wearable electronics are in great demand in recent years, and the silver nanowire (AgNW) flexible transparent electrode (FTE) is among the top candidates due to its excellent light transmittance and flexibility and the highest conductivity of silver among all metals. However, the conductivity of an AgNWs network has long been limited by the large contact resistance. Here we show a room-temperature solution process to tackle the challenge by nanojoining AgNWs with two-dimensional graphene oxide (GO). The conductivity of the AgNWs network is improved 18 times due to the enhanced junctions between AgNWs by the coated GOs, and the AgNW-GO FTE exhibits a low sheet resistance of 23 Ohm sq−1 and 88% light transmittance. It is stable under high temperature and current and their flexibility is intact after 1000 cycles of bending. Measurements of a bifunctional electrochromic device shows the high performance of the AgNW-GO FTE as a FTE.

Solution‐Processed h‐BN Film as an Alignment Layer for Liquid Crystal Devices: Realization of a Non‐Polymer Approach for Unidirectional Alignment over Unprecedentedly Large Areas

AbstractFabrication of liquid crystal devices heavily relies on the alignment layer providing the mandatory unidirectional orientation of the nematic molecules. Drawbacks of the traditional mechanically rubbed polymer layer have prompted to find better alternatives. However, cost‐effective methods for large‐area unidirectional alignment are still elusive. The latest attempt has been to use 2D materials deposited through the well‐known chemical vapor deposition process, invariably inviting all the associated complexities including high‐temperature processing, cumbersome transfer onto the required substrate, etc. Most importantly, the achieved domain size over which the nematic molecules exhibit unidirectional planar orientation, has been too small (sub‐mm2) for employable devices. Here, the authors present a room temperature solution process for obtaining h‐BN dispersion and directly depositing it as a film on the device substrate using the electrophoretic technique. The achieved layer far surpasses the size limitation mentioned above, resulting in unidirectional LC orientation over at least 4 cm2 and promising for much larger areas with the electrical and electro‐optic switching performance being comparable to an industry‐standard device. The success of this simpler method establishes 2D materials as strong contenders for achieving non‐contact LC alignment and, in a broader sense, brings the much‐needed impetus to explore new horizons for solution‐processed devices.

Design of novel self-assembled MXene and ZIF67 derivative composites as efficient electroactive material of energy storage device

High surface area and tunable pore size are beneficial for metal organic frameworks (MOFs) as electroactive material of energy storage devices. Novel ZIF67 derivative proposed in our previous work, nickel cobalt fluoride coupled with ammonia ions (NCNF), is synthesized using ammonia fluoride to solve poor electrical conductivity of MOFs. MXene is commonly incorporated in pseudo-capacitive materials to enhance electrical conductivity and energy storage ability. In this study, it is the first time to design MXene and NCNF composites (MXene/NCNF) with different MXene amounts via incorporating MXene in growing process of NCNF. MXene and NCNF are combined via self-assembly in a simple room temperature solution process. The optimized MXene/NCNF electrode shows a higher specific capacitance of 1020.0 F g−1 (170.0 mAh g−1) than that of NCNF electrode (574.2 F g−1 and 95.7 mAh g−1) at 20 mV s−1, due to excellent surface properties of MXene/NCNF with conductive network of MXene and high electrocapacitive performance of NCNF. A symmetric energy storage device composed of the optimized MXene/NCNF electrodes presents outstanding cycling stability with Coulombic efficiency of 100% during whole cycling process and a high capacitance retention of 99% after 6000 cycles. Excellent electrochemical performance and simple synthesis of MXene/NCNF open new blueprints for designing novel electrocapacitive materials for electrochemical applications.

Plasma Oxidized Ti3C2Tx MXene as Electron Transport Layer for Efficient Perovskite Solar Cells.

Recently, the two-dimensional material Ti3C2Tx MXene has attracted interest from researchers in perovskite solar cells (PSCs) with its great advantages in terms of high transmittance, high conductivity, tunable work function, and solution processability. However, the MXene-based PSC performance has still been inferior to that of the traditional TiO2- or SnO2-based counterpart up until now. Some critical issues regarding to the MXene/perovskite interface still have not been well addressed. Herein, we used the Ti3C2Tx MXene as electron transport layer in PSCs via a room-temperature solution process followed by oxygen plasma treatment. Various characterization techniques were taken to establish the correlation between the surface properties and termination groups of MXene. We showed that oxygen plasma treatment could break parts of Ti-C bonds and generate abundant Ti-O bonds randomly distributed on MXene. The surface modification resulted in tunable work functions of MXene, as well as reduced trap states and improved electron transport close to the interface. In addition, the surface tension of MXene and corresponding perovskite morphology were thoroughly investigated by the contact angle and topography measurements. High-resolution XPS spectra indicated the Pb-O interactions between perovskite and MXene, which contributed to the device stability improvement.

Tailoring the Structure of Low-Dimensional Halide Perovskite through a Room Temperature Solution Process: Role of Ligands.

In this study, halide perovskite nanocrystals are synthesized by controlling the ligand length and amount, and investigated the effects on the change in the ligand length and amount on the shape, size, crystal structure, and optical properties of the perovskite nanocrystals. The results reveal the tendency and respective effects of amine and acid ligands on perovskite nanocrystals. The amine ligands bind directly to the perovskite nanocrystals. Consequently, the amine ligands with longer chains interfere with the aggregation of the initially formed nanocrystals, thus limiting the size of the halide perovskite nanocrystals. Similar to the amine ligands, the acid ligands directly bond with the perovskite nanocrystals; however, they are also indirectly distributed around the nanocrystals, thus affecting their structure and dispersion. Consequently, the acid ligands affect the assembly of the initially formed nanocrystals, which determine the shape and crystal structure of the nanocrystals. It is believed that the report will provide useful insight on the synthesis of halide perovskites for application in optoelectronic devices.

Unusual effects of vacuum annealing on large-area Ag3PO4 microcrystalline film photoanode boosting cocatalyst- and scavenger-free water splitting

Ag3PO4 as a novel photoanode material, despite its arguably highest photoactivity, suffers for its poor light absorption and stability for photoelectrochemical (PEC) water oxidation. In this work, 4.5 × 4.5 cm2 Ag3PO4 microcrystalline films are grown via a room-temperature solution process, and vacuum annealing is proposed to solve the stability and light absorption issues. It is found that the major process below 400 °C of vacuum annealing is the |Recovery| process for Ag3PO4 microcrystals, when lattice defects and Ag0 surface species get reduced. Next, |Recrystallization| stage occurs at >400 °C. The recovery of native defects of silver vacancies, with both density functional theory calculation and experimental results, could simultaneously improve the light absorption and catalytic activity of Ag3PO4. The 400 °C-annealed Ag3PO4 photoanode, with enhanced light harvesting and crystal quality, exhibits 88% increase in (Jlight − Jdark) value (1.94 mA cm−2) than non-annealed photoanode (1.03 mA cm−2). Moreover, it retains >99% current density after a 4000-s stability test. These results suggest that vacuum annealing can substantially improve the PEC performance of Ag3PO4 microcrystalline film photoanodes due to mitigated effects of native defects, improved light harvesting, and inhibited Ag3PO4 decomposition during water oxidation reaction.

Structural, Electronic, and Optical Properties of Lead-Free Halide Double Perovskite Rb2AgBiI6: A Combined Experimental and DFT Study

Hybrid lead halide perovskites have emerged as an attractive photoactive semiconductor for optoelectronic applications such as photovoltaics. However, their toxicity and stability issues pose significant challenges to its wide-scale applications and hence the need to find alternative perovskites that are stable and environmentally benign. Recently, double perovskites have been suggested as a potential alternative owing to their non-toxicity and high stability. In the present study, we report the first synthesis of Rb2AgBiI6 thin films in a cubic crystal structure using a facile room-temperature single-step solution process synthesis method and explore their potential optoelectronic applications. The structural, thermal, and mechanical stability, electronic, and optical properties are studied using various experimental techniques, and the results are further corroborated by first-principles density functional theory (DFT) calculations. The Rb2AgBiI6 film has an estimated band gap ∼ of 1.98 eV with the demonstrated thermal stability of ∼ 440 oC, suggesting its potential suitability for low-cost thin-film solar cells. The initial fabricated photovoltaic device without optimization of the synthesis conditions and device architecture show power conversion efficiency (PCE) of 0.1 % and an open-circuit voltage (Voc) of 0.46 V. The successful incorporation of Rb in Bi-based double perovskite should open the way to a new class of Rubidium-based perovskites with significant potential for optoelectronic applications.

Nitrogen doped carbon nanotubes grafted TiO2 rutile nanofilms: Promising material for dye sensitized solar cell application

The TiO2 based solar cells are an exciting 3rd class generation photovoltaic, since they hold promise for the realization of large area devices that can be fabricated by room temperature solution processing, that can lead to high photoactive performance. Here, we reported similar efficiencies by focusing our work on obtaining sol-gel thin films belonging to N-CNT/TiO2 system by dispersing nitrogen doped carbon nanotubes (N-CNTs) powders in titanium tetra-isopropoxide using sol gel route. The film samples were evaluated in terms of structure morphology and optical properties using XRD analysis, atomic force microscopy (AFM) for TiO2, thin film scanning electron microscopy (SEM) for TiO2 and N-CNT/TiO2 thin films as well as UV–vis absorption spectroscopic techniques. X-ray diffraction analysis of films produced by the sol gel route and deposited on ITO glass has shown that they are also amorphous before annealing. However, XRD spectra showed only the peak of the rutile phase after the high annealing temperatures starting from 300 °C. The SEM micrographs showed the presence of grains of very small sizes, the grain size increases with the annealing temperature. The measurements made by AFM revealed that the thickness and roughness increase with the rise of annealing temperature of the film. 300 °C is the optimum temperature. This finding was assessed by the experimental investigation of annealing temperature effect through determination of specific area and pores diameter using BET and BJH methods respectively.Moreover, it was confirmed by SEM observations that the grains of N-CNT/TiO2 thin films are homogeneously dispersed and transmission electron microscopy clearly indicated that TiO2 grains are adsorbed on N-CNTs. Optical transmittance of N-CNT/TiO2 indicated a decrease with increasing the incorporated wt% N-CNTs. This behavior is due to charge carriers increase, which lead to band gap narrowing. The findings concerning the optical gap are assessed by electrical measurements. After careful analysis of the results presented in this work, we have deduced that the mentioned method is found to be simple and more efficient in the calculations of direct band gap.

Room-Temperature, Solution-Processed SiOx via Photochemistry Approach for Highly Flexible Resistive Switching Memory.

Due to its high versatility and cost-effectiveness, solution process has a remarkable advantage over physical or chemical vapor deposition (PVD/CVD) methods in developing flexible resistive random-access memory (RRAM) devices. However, the reported solution-processed binary oxides, the most promising active layer materials for their compatibility with silicon-based semiconductor technology, commonly require high-temperature annealing (>145 °C) and the RRAMs based on them encounter insufficient flexibility. In this work, an amorphous and uniform SiOx active layer was prepared by irradiating an inorganic polymer, perhydropolysilazane, with a vacuum ultraviolet of 172 nm at room temperature. The corresponding RRAM showed typical bipolar resistance switching with a forming-free behavior. The device on polyimide film exhibited outstanding flexibility with a minimum bending radius of 0.5 mm, and no performance degradation was observed after bending 2000 times with a radius of 2.3 mm, which is the best among the reported solution-processed binary oxide-based RRAMs and can even rival the performance of PVD/CVD-based devices. This room-temperature solution process and the afforded highly flexible RRAMs have vast prospects for application in smart wearable electronics.

GeTe-Based Alloy Films Prepared by a Room Temperature Solution Process.

This article describes the preparation of GeTe-based alloy films using a solution-based technique. The dissolution behavior of GeTe was initially examined by comparing the weight loss of GeTe powder in different solvents, and it was found that, unlike in the cases of n-butylamine and NH₄OH, KOH fully dissolved GeTe to form an agglomerate-free solution. X-ray diffraction analysis revealed that the reaction between GeTe and KOH resulted in the formation of rhombohedral GeTe, cubic GeTe₄, and hexagonal Te structures after drying. GeTe-based alloy films were then prepared by the spin coating of the GeTe-containing solutions on a silicon substrate. The surface morphology and reflectance properties of the prepared films were found to be highly dependent on the spin speed, with optimization of the spin coating parameter resulting in the deposition of a continuous and smooth film.

Enhanced performance and the related mechanisms of organic solar cells using Li-doped SnO2 as the electron transport layer

Electron transport layer (ETL), facilitating carrier separation and electron extraction, is a key component in organic solar cells (OSCs). Herein, Li-doped tin dioxide (Li:SnO2) prepared based on a simple room-temperature solution process and the following low-temperature annealing is introduced as the ETL of inverted OSCs with the P3HT:PC61BM bulk heterojunction. It is notable that compared to pristine SnO2, Li:SnO2 significantly boosts device performance benefiting from the comprehensive improvement including short-circuit current, open-circuit voltage and fill factor. As a result, ~62.9% increase in power conversion efficiency, i.e., from 2.21% to 3.60% is achieved for the device with optimized Li doping in SnO2 compared to the control device using pristine SnO2. The related mechanisms responsible for the improved performance are investigated. It is believed that this study may provide a valuable exploration to develop high-performance ETLs for OSCs.

Synthesis of N-CNT/TiO2 composites thin films: surface analysis and optoelectronic properties

In this study, we have investigated the surface analysis and optoelectronic properties on the synthesis of N-CNT/TiO2 composites thin films, using sol gel method for a dye synthetized solar cell (DSSC) which is found to be simple and economical route. The titanium dioxide based solar cells are an exciting photovoltaic candidate; they are promising for the realization of large area devices. That can be synthetized by room temperature solution processing, with high photoactive performance. In the present work, we stated comparable efficiencies by directing our investigation on obtaining Sol Gel thin films based on N-CNT/TiO2, by dispersing nitrogen (N) doped carbon nanotubes (N-CNTs) powders in titanium tetraisopropoxyde (TTIP). The samples were assessed in terms of optical properties, using UV—visible absorption spectroscopic techniques. After careful analysis of the results, we have concluded that the mentioned route is good and more efficient in terms of optoelectronic properties. The gap of “the neat” 0.00w% N-CNT/TiO2 is of 3eV, which is in a good agreement with similar gap of semiconductors. The incorporated “w%NCNTs” led to diminishing the Eg with increasing N-CNTs amount. These consequences are very encouraging for optoelectronic field.

γ-Fe2O3 as a novel Electron Transporting Material for Planar Heterojunction Perovskite Solar Cells by simple Room-Temperature Solution method

α-Fe2O3 has been demonstrated to be a promising electron transporting material (ETL) for fabricating efficient perovskite solar cells (PSCs) with good stability under ultraviolet light compared to the commonly used TiO2. However, α-Fe2O3 films need to be processed over 500 °C, which is a serious impediment to fabricate devices on the flexible substrates. Herein, γ-Fe2O3, which could be deposited onto the substrates under room temperature, would be an alternative magnetic ETL with a reasonable performance. We report that pure and fine nano-sized γ-Fe2O3 particles can be synthesized below 200 °C and the corresponding compact layers have been fabricated by a simple room-temperature solution process. The methylammonium lead iodide (MAPbI3) PSCs based on γ-Fe2O3 show a power conversion efficiency of 12.86% with a short circuit current (Jsc) of 21.79 mA/cm2, an open circuit photovoltage (Voc) of 0.93 V and a fill factor (FF) of 63.3%. These results indicate a possible direction for preparing flexible perovskite solar cells.

Room-temperature solution-processed, ZrOx-based hybrid gate dielectrics for low-voltage organic thin-film transistors on plastic substrates

For advanced electronic device applications including printable, flexible organic electronics and bioelectronics, it is crucial to develop novel dielectric materials with high dielectric strength and low-temperature processability compatible with plastic substrates for producing flexible and low-voltage organic thin-film transistors (OTFTs). Herein, we report the facile fabrication of rationally designed, high-capacitance hybrid gate dielectric films for low-voltage OTFTs on plastic substrates via a room-temperature solution process. To create room-temperature-processed gate dielectrics with high dielectric strength, we designed organic-inorganic hybrid gate dielectric films by including ZrOx networks as inorganic high-k oxide materials for obtaining large capacitance and 1,6-hexanediol diacrylate as a bifunctional UV cross-linking agent and a flexible organic component for increasing the density and flexibility of films and ensuring room-temperature processability. The UV cross-linked ZrOx-based hybrid composite films with a 15 nm thickness showed excellent dielectric properties with a leakage current density of ∼10−6 A/cm2 and a capacitance of 640 nF/cm2. The film surfaces were modified with hydrophobic self-assembled monolayers to match the surface energy of organic semiconductors for enhancing the OTFT performance. The utility of the hybrid dielectrics for flexible OTFTs was demonstrated by realizing pentacene TFTs on plastic substrates with a low operating voltage at –2.5 V, a high on/off current ratio of 105, a threshold voltage as low as –0.7 V, and a hole mobility up to 0.47 cm2 V−1 s−1, which are comparable to those performed on Si substrates.

Vacuum Ultraviolet Photochemical Sol-Gel Processing of Zn, Sn, Zn-Sn Oxide Thin Films for Encapsulation of Organic Light Emitting Diodes

Room temperature solution processing of highly compact, glass-like thin films of ZnO, SnO2 and Zn-Sn oxide was achieved for the purpose to use them as thin film encapsulations (TFEs) for organic light emitting diodes (OLEDs), by employing photochemical decomposition of metallorganic precursors under vacuum ultraviolet irradiation in dry N2. While hydration water in the source chemical strongly promoted granular crystal growth, anhydrous precursors achieved highly flat thin films without pinholes and cracks. The analysis by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and ellipsometry revealed fast decomposition of organic ligand and polycondensation into metal oxide/hydroxide thin films with high densities within 5 minutes. Transmission electron microscopic observation revealed crystallization in about 5 nm size in case of ZnO, whereas SnO2 remained totally amorphous. Mixing of the two precursors to yield Zn2SnO4 and ZnSnO3 was able to control the degree of crystallization vs. compactness of the thin film to maximize their ability as TFEs to extend the lifetime of OLEDs for about 4 times for operation under ambient air.

Vacuum Ultraviolet-Assisted Sol-Gel Processing of Zn, Sn, Zn-Sn Oxide Thin Films for OLED Encapsulation

Room temperature solution processing of highly compact, glass-like thin films of ZnO, SnO2 and Zn-Sn oxide was achieved for the purpose to use them as thin film encapsulation (TFE) for flexible film organic light emitting diodes (OLEDs), by employing photochemical decomposition of metalorganic precursors under vacuum ultraviolet (VUV) irradiation. Care had to be taken to control the amount of water in the coating solution since hydration water in the precursor compound already gave a strong influence to promote granular crystal growth. With anhydrous precursors, highly flat thin films without pinholes and cracks could be obtained. The analysis by FTIR and ellipsometry revealed fast decomposition of organic ligand and polycondensation to metal oxide thin films with high densities within 5 minutes. TEM observation in fact revealed crystallization into ZnO in about 5 nm size, despite the reaction was carried out in the absence of water and under N2. Since the process does not require a high temperature, O2 condition and H2O to harm OLED devices, these metal oxides could be applied to OLEDs as TFEs to extend their lifetime for 3-4 times.

Thick TiO2-Based Top Electron Transport Layer on Perovskite for Highly Efficient and Stable Solar Cells

Simultaneously achieving high efficiency, long-term stability, and robust fabrication with good reproducibility in perovskite solar cells (PVSCs) is essential for their practical applications. Herein, we first demonstrate a thick TiO2 backbone film directly on top of a perovskite film through a simple room-temperature solution process. Through the strategy of decorating the TiO2 film with fullerene for passivating traps and filling voids, we achieve a fullerene-decorated TiO2 electron transport layer (ETL) in inverted PVSCs. Because of the suppressed monomolecular Shockley–Read–Hall recombination and ion diffusion of the fullerene-decorated TiO2 ETL, stabilized efficiencies of ∼20% and shelf life stability remaining over 98% of initial efficiency after aging in ambient conditions or 16 months are achieved. Remarkably, the PVSCs are insensitive to TiO2 thickness from 50 to 250 nm, which contributes significantly to the robust fabrication and high reproducibility of the PVSCs. This work provides an ETL desi...

Solution-Based Facile Fabrication of Heterojunction for Silicon Solar Cells Using Graphene Quantum Dots and PEDOT:PSS

Silicon remains the most widely employed material in solar cell due to the low cost, lack of toxicity, and small electronic band gap for near-infrared to visible light absorption. However, up to now, one of the main limitations of silicon solar cells is their high temperature and complex manufacturing processes. Recently, silicon solar cells hybridized with material like organic, semiconductor quantum dots, have attracted a great deal of research interest owing to their promise of room-temperature manufacturing and solution processing capability. But the problems of poor mobilities and toxicity need to be solved urgently. Fortunately, zero-dimensional graphene quantum dots (GQDs) have lately intrigued intensive interest in the field of energy and optoelectronic due to the tunable bandgap, emission in a range of visible light, longer hot carrier lifetimes, chemical stability and low toxicity. In addition to the low-cost and environment-friendly properties, GQDs could act as blocking layer to facilitate the separation of photo-generated electron-hole pairs and suppress the carrier recombination, thus increase the power conversion efficiency (PCE) in solar cells. Here in, we present a solution-based, facile fabrication of silicon heterojunction solar cells using GQDs and poly(3,4-etyhlenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). The PEDOT:PSS/n-Si cell showed a PCE of 8.86%, and the application of GQDs to the PEDOT:PSS/n-Si interface enhanced the PCE to 10.24%. The passivation of n-Si surface by quick annealing in vacuum at 500 °C for 10 min enhanced the PCE further to 11.77%. The quick processes for heterojunction formation and surface passivation would be well suited for low-cost fabrication of solar cells based on crystalline Si thin films.

Halide Perovskites for Selective Ultraviolet-Harvesting Transparent Photovoltaics

Summary Halide perovskite materials have emerged as a potential Si replacement with excellent photovoltaic properties. There has been growing interest in applying halide perovskites to semitransparent and spatially segmented transparent photovoltaics (TPVs) to enable a greater range of deployment routes. However, the continuous-band absorption of these semiconductors prevents near-infrared selective harvesting typically targeted for TPVs with the highest efficiency and transparency needed to meet the aesthetic demands of many potential applications. In this work, we demonstrate TPVs based on perovskite semiconductors where the band gap is sensitively tuned with a range of compositions to selectively harvest only ultraviolet photons with band gaps between 410 and 440 nm. This approach offers theoretical efficiencies up to 7% with >99% visible transparency when precisely targeting band gaps around 435 nm. Practical optimization of these perovskite cells could quickly yield TPVs with power conversion efficiencies rivaling state-of-the-art near-infrared harvesting TPVs today while also providing a route to higher-efficiency multi-junction TPVs.

Anti-biofilm activity and food packaging application of room temperature solution process based polyethylene glycol capped Ag-ZnO-graphene nanocomposite

Present work reports on synthesis and anti-biofilm activity as well as food packaging application of Ag–ZnO–reduce graphene oxide (rGO)–polyethylene glycol (PEG) (AZGP) nanocomposites via adopting room temperature solution process by varying silver nitrate content (up to 0.1 M) with fixed content of graphene oxide and PEG used in the precursors. Presence of Ag and ZnO nanoparticles (NPs) distributed uniformly over rGO nanosheets has been confirmed by X-ray diffraction and transmission electron microscopic analyses whereas FTIR, Raman, UV–Visible and X-ray photoelectron spectral studies have been performed to confirm the existence of chemical interaction/complexation that happened between the available oxygen functionalities of rGO and PEG with the inorganic moieties (Ag–ZnO/Zn2+) of AZGP samples. A formation mechanism of AZGP nanocomposite is proposed based on the experimental results. Anti-biofilm activity has been studied on Staphylococcus aureus and Pseudomonas aeruginosa bacteria to confirm the efficiency of the nanocomposites for killing the bacterial cells. It is found that 0.05 M silver nitrate based AZGP nanocomposite at 31.25 μg/mL sample dosage shows about 95% inhibition activity towards the biofilm formation as well as eradication of preformed biofilm. Also, agar based AZGP film has been fabricated and characterized by X-ray diffraction study for the purpose of food packaging application. Textural analysis of agar based film shows an enhanced film tensile strength. The film also shows an excellent antimicrobial activity even after keeping it for a prolong period of about 90 days. This cost effective simple synthesis strategy can make an avenue for development of Ag incorporated other biocompatible metal oxide based rGO–PEG nanocomposites for potential food packaging application.