Transparent Conductive Oxide Electrode Research Articles

Non-destructive buffer enabling near-infrared-transparent inverted inorganic perovskite solar cells toward 1400 h light-soaking stable perovskite/Cu(In,Ga)Se2 tandem solar cells

Near-infrared (NIR) transparent inverted all-inorganic perovskite solar cells (PSCs) are excellent top cell candidates in tandem applications. An essential challenge is the replacement of metal contacts with transparent conductive oxide (TCO) electrodes, which requires the introduction of a buffer layer to prevent sputtering damage. In this study, we show that the conventional buffers (i.e., small organic molecules and atomic layer deposited metal oxides) used for organic-inorganic hybrid perovskites are not applicable to all-inorganic perovskites, due to non-uniform coverage of the vulnerable layers underneath, deterioration upon ion bombardment and moisture induced perovskite phase transition. A thin film of metal oxide nanoparticles by the spin-coating method serves as a non-destructive buffer layer for inorganic PSCs. All-inorganic inverted near-infrared-transparent PSCs deliver a PCE of 17.46% and an average transmittance of 73.7% between 780 and 1200 nm. In combination with an 18.56% Cu(In,Ga)Se2 bottom cell, we further demonstrate the first all-inorganic perovskite/CIGS 4-T tandem solar cell with a PCE of 24.75%, which exhibits excellent illumination stability by maintaining 86.7% of its initial efficiency after 1400 h. The non-destructive buffer lays the foundation for efficient and stable NIR-transparent inverted inorganic perovskite solar cells and perovskite-based tandems.

Efficient Micrometer Thick Bifacial Perovskite Solar Cells

AbstractPerovskite solar cells have become promising candidates for thin‐film photovoltaics (PV), but many record cells suffer from losses in current (≈3–4 mA cm−2). This is due to the choice of superstrate configurations (i.e., glass‐side illumination) and thin absorber layers, typically on the order of ≈500 nm. Illumination through a top transparent conductive oxide electrode (substrate configuration) using LiF and Al2Ox as anti‐reflective coatings leads to reflectance losses below 1% is demonstrated. When combined with 1 µm thick absorber layers, substrate configurated bifacial devices have power conversion efficiencies >20%, with minimized reflection losses approaching 98% of their detailed‐balance limits and higher Jsc than their monofacial counterparts. Further analysis is conducted to show there is still a significant fraction of current lost due to poor charge‐carrier extraction (e.g., resistive or low mobility contacts). This is studied by a direct comparison of photoluminescence at short‐circuit versus open‐circuit estimating a 4.5% loss in charge‐carrier collection.

Impact of atomic layer deposition temperature on electrical and optical properties of ZnO:Al films

This work highlights the impact of growth temperature on the electrical and optical properties of Al-doped ZnO (AZO) films deposited by the atomic layer deposition (ALD) technique. The ALD process and super-cycle sequence have been optimized, identifying their influence on film resistivity. By using this optimum ALD procedure, the optical and electrical properties of AZO films have been widely analyzed considering the deposition temperature. Results show promising values with film resistivity in the range of 1 mΩcm and average optical absorption below 2% for 50 nm thick AZO layers. Hall effect, X-ray diffraction and ellipsometry measurements point out that these excellent values are related to their high carrier concentration and mobility, crystalline phase and optical band gap, resulting in ALD AZO films with excellent properties to be applied in photovoltaic devices as transparent conductive oxide electrode.

Pockels Effect of Interfacial Water on a Mono-Electrode Induced by Current Parallel to the Electrode Surface

When an electric field is applied between two electrodes facing each other immersed in a liquid, the interfacial Pockels effect, a refractive index change proportional to the electric field, occurs in the electric double layer at the liquid–electrode interface. Here, we report that the Pockels effect of interfacial water can be observed even when an electric field is applied parallel to the surface of a “single” electrode in an electrolyte solution. This is a non-trivial result since the electric field parallel to the interface should not cause a broken spatial inversion symmetry, which is required for the Pockels effect. The Pockels signal was detected as a change in the transmitted light intensity due to the field-induced spectral shift of the interference fringes of the transparent conductive oxide electrode layer on a glass substrate. The magnitude of the signal increased as it approached the ends of the electrode, and the sign reversed across the center of the electrode. The electric field distribution calculated from the interfacial potential difference due to the in-plane parallel current showed that an electric field perpendicular to the interface was induced, whose distribution was consistent with the position dependence of the Pockels signal. A similar phenomenon was also observed for a single copper electrode, confirming that this is a universal effect.

Solution‐Processed Bifacial Cu(In, Ga)(S, Se)2 Thin‐Film Solar Cells with a Frontside Power Efficiency of 9.73%

Cu(In, Ga)(S, Se)2 (CIGSSe) solar cell is one of the most promising thin‐film solar cells with a record power conversion efficiency (PCE) of 23.6%. Conventional CIGSSe thin‐film solar cells are usually fabricated on Mo‐coated soda‐lime glass substrate, thereby, the sunlight on the rear side cannot be utilized by the monofacial CIGSSe solar cells owing to the opacity of the Mo electrode. CIGSSe solar cells fabricated on transparent conductive oxide (TCO) electrode enable to fabricate bifacial solar cells, which can generate power on both sides of solar cells, so that bifacial solar cells have a high potential application in building‐integrated photovoltaics. However, the PCEs of CIGSSe solar cells fabricated on TCO substrates are significantly lower than those of ones on Mo substrates. In this article, bifacial CIGSSe solar cells on fluorine‐doped tin oxide (FTO) substrate are fabricated by using an ionic liquid‐assisted solution approach and utilizing a MoO3 thin film as an interface layer between FTO and CIGSSe absorber layer, yielding a front‐side PCE of 9.73% and a back‐side PCE of 1.77%.

Nb (V, Nb/V)-Doped TiO2 Films as New Transparent Conducting Oxides Synthesized by a Novel ALD Process: Effect of Dopant Content and Growing Conditions

Titanium oxide (TiO2) is a wide bandgap (3.0-3.4 eV) material that presents a high transparency in the visible range, a high refractive index, and an insulator behavior. In order to vary its structural, optical, and electronic properties with the objective to synthesize transparent conductive oxide (TCO) films, we have investigated several doping strategies. Due to their extra electron and atomic radius close to that of Ti, respectively larger for Nb or smaller for V, these are among the interesting potential dopants of TiO2. In this objective to synthesize TiO2-based TCO films, we have performed atomic layer deposition (ALD) with different concentrations of Nb dopants and by varying the growth conditions.Highly transparent and conducting Nb-doped TiO2 thin films were produced by a low-temperature (300 °C) new ALD process using titanium tetraisoproxide, niobium(V) ethoxide, and water as a reagent. The deposition was performed in a supercycle fashion, alternating Ti precursor and water cycles followed by Nb precursor and water cycles, which allowed controlling the dopant concentration. This study focused on non-annealed and annealed films under N2 and forming gas. The dopant concentration significantly affected the fabricated films' thickness, structure, morphology, composition, and optical and electrical properties. Indeed, the crystalline anatase phase was obtained before annealing for a low Nb content, while the films were found amorphous for a larger Nb content. The non-annealed film thickness and surface roughness decreased with increasing Nb doping, while the size of the anatase grains increased, and the films became amorphous. This progressive amorphization of the films with increasing Nb content was observed by several techniques (G-XRD, Raman, and FTIR). Surprisingly, films annealed at 600°C led to the formation of larger and more homogeneous grains than for non-annealed films. Moreover, the XRD, Raman, and FTIR results clearly indicated the substitution of Ti by Nb in the anatase structure. Furthermore, the XPS spectra showed that the amount of Ti and Nb in the Ti3+ and Nb4+ oxidation states increased with increasing the Nb content. These two latter points may explain the decrease in resistivity caused by the increase of density of shallow donor states in addition to the decrease of electrons scattering caused by the grain size increase. In addition, the film transmittance was increased up to 15% while the resistivity decreased to 10-3 Ω.cm leading to a TCO behavior. Using the figure of Merit (FoM) established over a wide spectral range from AM1.5g irradiance [*] giving the maximum photocurrent density of an ideal solar cell equipped with such TCO electrode, it showed an improvement by a factor of 8 by Nb doping, reaching a maximum of FoM for the film produced with a particular Nb doped rate of 0.33.Other strategies of TCO improvement were investigated, such as growing V-doped, and Nb&V co-doped TiO2 films by innovative dual and triple precursors ALD processes, respectively. Once more, the dopant kind and amount strongly impacted the growth rate, structure, morphology, optical and electrical properties of those two new kinds of doped TiO2 materials. The full study of Nb-doped TiO2 films will be presented, while the comparative results obtained for V-doped and Nb/V-doped materials will be introduced.The Nb-doped TiO2's TCO performances and future improvement based on V-doped, and Nb&V co-doped may pave the way for the use of those kinds of materials in solar radiation energy conversions as electrode or junction materials for Photovoltaic or photo(electro)catalytic systems.[*] J.A. Mendez-Gamboa, R. Castro-Rodriguez, I. V. Perez-Quintana, R.A. Medina-Esquivel, A. Martel-Arbelo, A figure of merit to evaluate transparent conductor oxides for solar cells using photonic flux density, Thin Solid Films. 599 (2016) 14–18. https://doi.org/10.1016/j.tsf.2015. .12.038. Figure 1

Multiresonant Grating to Replace Transparent Conductive Oxide Electrode for Bias Selected Filtering of Infrared Photoresponse.

Optoelectronic devices rely on conductive layers as electrodes, but they usually introduce optical losses that are detrimental to the device performances. While the use of transparent conductive oxides is established in the visible region, these materials show high losses at longer wavelengths. Here, we demonstrate a photodiode based on a metallic grating acting as an electrode. The grating generates a multiresonant photonic structure over the diode stack and allows strong broadband absorption. The obtained device achieves the highest performances reported so far for a midwave infrared nanocrystal-based detector, with external quantum efficiency above 90%, detectivity of 7 × 1011 Jones at 80 K at 5 μm, and a sub-100 ns time response. Furthermore, we demonstrate that combining different gratings with a single diode stack can generate a bias reconfigurable response and develop new functionalities such as band rejection.

Carbon-Based Electrodes for Organic Solar Cells.

Organic solar cells (OSCs) are a promising low-cost thin-film photovoltaic technology while the fabrication of transparent conductive oxide (TCO) and metal electrodes still remains a factor that hinders the scaling-up and commercialization of OSCs. Carbon-based materials are regarded as potential alternatives due to their excellent properties, such as low cost, solution processibility, high conductance, and good chemical stability. In this mini-review, the recent progress of carbon-based materials such as graphite, carbon nanosheets, graphene, and carbon nanotubes to replace the TCO and metal electrodes of OSCs is surveyed. The preparation methods of different carbon-based materials are also discussed. Based on current progress, we summarize the outlooks and challenges of carbon-based electrodes. We anticipate this mini-review will inspire more research efforts to develop high-performance and OSC-matched carbon materials for more efficient and stable carbon-electrode-based OSCs.

ПОЛИАРИЛЕНЭФИРКЕТОНЫ В КАЧЕСТВЕ ПРОВОДНИКА В ТОКОСЪЕМНОЙ СИСТЕМЕ СОЛНЕЧНОГО ЭЛЕМЕНТА

The paper investigates the thermomechanical and electrical properties of a number of thermoplastic copolymers poly(arylene ether ketones) (co-PAEK) containing fluorene groups in the main chain of the macromolecule. Co-PAEKs are being studied for the purpose of their use in the contact system of a solar cell with a transparent conductive oxide (TCO) electrode and a multiwire contact grid. Polymer films are used as conductive adhesives to form an electrical contact between metal wire and TCO. The formation of an electrically conductive contact occurs during lamination at an excess pressure of 1 atm and a temperature of maximum deformation of co-PAEK, while the copolymer switches from the initial dielectric to a stable highly conductive state. Co-PAEKs with the content of fluorene groups ( q ) 5, 10, 15, 20 and 25 mol.% are synthesized, having the same molecular weight and the reduced viscosity of ~0.38 dl/g. To select the optimal contact system formation temperature for each coPAEK, the glass transition temperature ( T g) and the peak strain temperature ( T d) were determined from thermo mechanical curves. It was found that with increasing q , the temperature T g increases from 162 to 185°С, and T d from 203 to 223°С. The specific contact resistances (ρС) in the metal wire/co-PAEK/TCO (ITO - In2O3:Sn) system were determined for a round copper wire coated with indium:tin (In:Sn) solder, as well as for tin-plated wire, depending on the content of fluorene groups in the copolymer. The specific contact resistance ρС for wire with (In:Sn) solder varies in the range of 0.56-0.83 mΩ cm2, for tin-plated wire - 0.84-1.43 mΩ cm2, and co-PAEK with q = 5 mol % showed the lowest ρС in both cases. The ρC of wire/co-PAEK/ITO contacts has been studied as a function of the resistivity of ITO grown by ultrasonic spray pyrolysis on silicon substrates. The temperature dependence of the resistivity of the wire/co-PAEK/ITO contact was studied in the temperature range of 5-85°C, and a conclusion was made about the metallic type of dependence. According to the results of microscopic studies of the contact area, the typical minimum co-PAEK layer thickness between the wire and ITO after the formation of the contact was determined, which is in the range of 0.5-2.4 μm.

Tripodal Triazatruxene Derivative as a Face-On Oriented Hole-Collecting Monolayer for Efficient and Stable Inverted Perovskite Solar Cells.

Hole-collecting monolayers have drawn attention in perovskite solar cell research due to their ease of processing, high performance, and good durability. Since molecules in the hole-collecting monolayer are typically composed of functionalized π-conjugated structures, hole extraction is expected to be more efficient when the π-cores are oriented face-on with respect to the adjacent surfaces. However, strategies for reliably controlling the molecular orientation in monolayers remain elusive. In this work, multiple phosphonic acid anchoring groups were used to control the molecular orientation of a series of triazatruxene derivatives chemisorbed on a transparent conducting oxide electrode surface. Using infrared reflection absorption spectroscopy and metastable atom electron spectroscopy, we found that multipodal derivatives align face-on to the electrode surface, while the monopodal counterpart adopts a more tilted configuration. The face-on orientation was found to facilitate hole extraction, leading to inverted perovskite solar cells with enhanced stability and high-power conversion efficiencies up to 23.0%.

Indium-based transparent conductive oxides developed for perovskite and perovskite-silicon tandem solar cell applications

Silicon solar cells are a mature PV technology; however, they are approaching their fundamental efficiency limit. Further efficiency improvements require a technological change towards silicon-based tandem solar cells, where a second absorber material with a higher band gap is stacked on top of silicon to reduce thermalization losses. For this purpose, perovskite-based solar cells have gained growing interest due to their rapid improvements in power conversion efficiencies, and promises of lower levelized costs of electricity. However, for perovskite-silicon tandem solar cells to surpass the current industry standard of silicon solar cells, efficiencies higher than 30 %, and long-term device stability are required.This paper focuses on the goal of improving the overall device efficiency of perovskite-silicon tandem solar cells by optimization of the top transparent conductive oxide (TCO) electrode. Sputtering processes for the TCOs indium tin oxide (ITO) (standard DC sputtering with ceramic target) and indium zinc oxide (IZO) (reactive serial co-sputtering process - magnetron) were developed and investigated. TCO films were optimized with regard to their optical properties, quantified here as the absorption weighted with solar spectral data, as well as to their electrical characteristics assessed with 4-pt resistivity and Hall-effect measurements to quantify resistivity, carrier concentration, and mobility. The best performing TCOs were then integrated as front electrode in perovskite and perovskite-silicon tandem solar cells to evaluate their impact on the device level. The optimized IZO film resulted in up to 1 mA/cm2 improvement of short circuit current density of the tandem solar cells.

Perovskite/Perovskite Tandem Solar Cells in the Substrate Configuration with Potential for Bifacial Operation.

Perovskite/perovskite tandem solar cells have recently exceeded the record power conversion efficiency (PCE) of single-junction perovskite solar cells. They are typically built in the superstrate configuration, in which the device is illuminated from the substrate side. This limits the fabrication of the solar cell to transparent substrates, typically glass coated with a transparent conductive oxide (TCO), and adds constraints because the first subcell that is deposited on the substrate must contain the wide-bandgap perovskite. However, devices in the substrate configuration could potentially be fabricated on a large variety of opaque and inexpensive substrates, such as plastic and metal foils. Importantly, in the substrate configuration the narrow-bandgap subcell is deposited first, which allows for more freedom in the device design. In this work, we report perovskite/perovskite tandem solar cells fabricated in the substrate configuration. As the substrate we use TCO-coated glass on which a solution-processed narrow-bandgap perovskite solar cell is deposited. All of the other layers are then processed using vacuum sublimation, starting with the charge recombination layers, then the wide-bandgap perovskite subcell, and finishing with the transparent top TCO electrode. Proof-of-concept tandem solar cells show a maximum PCE of 20%, which is still moderate compared to those of best-in-class devices realized in the superstrate configuration yet higher than those of the corresponding single-junction devices in the substrate configuration. As both the top and bottom electrodes are semitransparent, these devices also have the potential to be used as bifacial tandem solar cells.

Electrochromic polymers based on 3,5-di(9H-carbazol-9-yl)benzonitrile and bithiophene as anodically coloring films for high-contrast and rapid switching electrochromic devices

• A CzBN-containing homopolymer is electrosynthesized. • P(CzBN- co -BTP4) displays three various colors (brown, grayish-blue, and olive green) at different potentials. • P(CzBN- co -BTP) attains high Δ T (59.6 % at 960 nm) and η (174.3 cm 2 /C at 960 nm). • P(CzBN- co -BTP2)/PEDOT ECD presents a high Δ T (43.7 % at 627 nm). A 3,5-di(9H-carbazol-9-yl)benzonitrile (CzBN)-containing homopolymer (P(CzBN)) and five CzBN-containing 2,2′-bithiophene (BTP) copolymers, namely (P(CzBN- co -BTP)), P(CzBN- co -BTP2), P(CzBN- co -BTP3), P(CzBN- co -BTP4), and P(CzBN2- co -BTP), with various feeding molar ratios of CzBN and BTP were electrodeposited on transparent conductive indium tin oxide (ITO) electrodes, and their electrochromic performances were characterized. The P(CzBN- co -BTP4) film exhibited distinct electrochromic behaviors and displayed three different colors (brown, grayish-blue, and olive green) at different potentials. Electrochromic kinetic analyses of the anodic polymers revealed that P(CzBN- co -BTP) had a high transmittance change (Δ T %) (59.6% at 960 nm) and high coloration efficiency (η) (174.3 cm 2 /C at 960 nm) in three-electrode cells. Six dual-layer organic electrochromic devices (ECDs) were constructed using P(CzBN), P(CzBN- co -BTP), P(CzBN- co -BTP2), P(CzBN- co -BTP3), P(CzBN- co -BTP4), or P(CzBN2- co -BTP) as the anodically coloring layers and PEDOT as the cathodically coloring layer. The P(CzBN- co -BTP2)/PEDOT ECD had a high Δ T (43.7% at 627 nm) and a rapid response time (≤2.0 s), while the P(CzBN)/PEDOT ECD had a high η (616.7 cm 2 /C at 625 nm) and adequate optical memories. These electrochromic results suggest that cyano-containing polycarbazoles are promising high-contrast and rapid-response electrodes for ECD applications.

MgZnO High‐Voltage Transparent Thin‐Film Transistors Built on Glass

Recently, there has been increasing interest in building‐integrated photovoltaic (BIPV), which enables harvesting solar energy effectively. Large‐area glass components such as windows are widely used in modern constructions. In addition to the PV on opaque components such as walls and roofs, the transparent photovoltaic (TPV) directly built on glass is complementary to fully utilize the PV energy in BIPV. A high‐voltage transparent thin‐film transistor (HVTTFT) built on glass is an ideal option for distributed microinverters for TPV modules. A wide‐bandgap oxide‐based HVTTFT on glass for this purpose is reported. The HVTTFT on glass uses ZnO‐based materials with different functions for two roles: a semiconductor Mg0.01Zn0.99O (MZO) as TFT channel and Al‐doped ZnO (AZO) as transparent conductive oxide (TCO) electrodes. The centrosymmetric circular structure of the MZO HVTTFT with a high‐k‐stacking gate dielectric enables a blocking voltage as high as ≈1 kV and an on/off ratio of 106. The device exhibits an average optical transmittance of 81% over the visible spectrum.

Surface Morphology of Textured Transparent Conductive Oxide Thin Film Seen by Various Probes: Visible Light, X-rays, Electron Scattering and Contact Probe.

Fluorine-doped tin oxide thin films (SnO2:F) are widely used as transparent conductive oxide electrodes in thin-film solar cells because of their appropriate electrical and optical properties. The surface morphology of these films influences their optical properties and therefore plays an important role in the overall efficiencies of the solar cells in which they are implemented. At rough surfaces light is diffusely scattered, extending the optical path of light inside the active layer of the solar cell, which in term improves light absorption and solar cell conversion efficiency. In this work, we investigated the surface morphology of undoped and doped SnO2 thin films and their influence on the optical properties of the films. We have compared and analysed the results obtained by several complementary methods for thin-film surface morphology investigation: atomic force microscopy (AFM), transmission electron microscopy (TEM), and grazing-incidence small-angle X-ray scattering (GISAXS). Based on the AFM and TEM results we propose a theoretical model that reproduces well the GISAXS scattering patterns.

Enhanced optoelectronic properties of magnetron sputtered ITO/Ag/ITO multilayers by electro-annealing

Indium tin oxide/silver/indium tin oxide (ITO/Ag/ITO) multilayers have attracted much attention to fulfill the growing need for high-performance transparent conducting oxide electrodes. To make these transparent multilayers work better, electro-annealing, which is a method of self-heating by electric current, can be effective. Moreover, the effect of current on ITO/Ag/ITO multilayers should be investigated to make sure that electronic devices will be reliable over their lifetime. In this study, ITO/Ag/ITO multilayer electrodes with varying Ag thicknesses were grown by DC magnetron sputtering at room temperature. Structural, optical, and electrical properties of these multilayers were investigated before and after electro-annealing. Measurement results revealed that improved optical transmittance and sheet resistance can be obtained by the optimization of Ag thickness for the as-grown ITO/Ag/ITO layers. The highest figure of merit (FoM) value of 17.37 × 10−3 Ω−1 with optical transmittance of 85.15% in the visible region and sheet resistance of 11.54 Ω/□ was obtained for the Ag thickness of 16.5 nm for as-grown samples. The electro-annealing of as-grown ITO/Ag/ITO multilayers led to improved optical behavior of the multilayer structure over a wide spectral range, especially in the near-infrared range. Electro-annealing also provided an improvement in the crystallinity and sheet resistance of the electrodes. The improvement of the electrical and optical properties of the structure enabled a FoM of 23.07 × 10−3 Ω−1 with the optical transmittance of 86.80% in the visible region and sheet resistance of 10.52 Ω/□. The findings of this work provide proper knowledge of the properties of ITO/Ag/ITO multilayers under electrical current and suggest that the overall performance of the multilayers can be improved by the electro-annealing process.

TCO-free perovskite solar cells in taking advantage of SWCNT/TiO2 core/shell sponge

A nanohybrid of titanium dioxide (TiO 2 ) and single-walled carbon nanotubes (SWCNTs) with dual functions of collecting electrons and transparent electrode layer is synthesized by nano-cluster deposition technology. The super-hollow structure of the SWCNTs was directly fabricated via arc discharge and fully covered with a thin layer (∼15 nm) of TiO 2 , which formed the SWCNT/TiO 2 core/shell sponge. The developed SWCNT/TiO 2 core/shell sponge is used directly as scaffolding for a light absorber and electron collector in transparent conducting oxide (TCO) electrode-free perovskite solar cells (PSCs) for the first time, which exhibited a power conversion efficiency of 7.2%. The large surface area of the core/shell bundle is sufficiently effective in transferring the photogenerated electron from the Perovskite absorber to the SWCNTs. More importantly, the findings of this work could support the concept of replacing the conventional TCO in PSCs and pave the way to further work for developing inexpensive and flexible PSCs. • Replacing conventional transparent conducting oxide electrode with carbon nanotube in perovskite solar cell. • Dual functions of SWCNT/TiO 2 core/shell sponge as electron collector and scaffold for light absorber. • The photovoltaic performance of SWCNT and FTO-based devices was shown in comparative investigation. • The use of high quality SWCNT/TiO 2 sponge was believed in further development of low-cost PSC.

Boosting Electrochemical Activity of Porous Transparent Conductive Oxides Electrodes Prepared by Sequential Infiltration Synthesis.

Sequential infiltration synthesis (SIS) is an emerging technique for producing inorganic-organic hybrid materials and templated inorganic nanomaterials. The application space for SIS is expanding rapidly in areas such as lithography, filtration, photovoltaics, antireflection, and triboelectricity, but not in the field of electrochemistry. This study performs SIS for the fabrication of porous, transparent, and electrically conductive films of indium zinc oxide (IZO) to evaluate their potential as an electrode for electrochemistry. The electrochemical activity of IZO-coated electrodes is evaluated when their surfaces are modified with ferrocenecarboxylic acid (FcCOOH), a model redox molecule. Results show a 25-fold enhancement in peak current densities mediated by an Fc/Fc+ redox couple for an IZO-coated electrode in comparison with bare electrodes; this is afforded by the porous morphology of the IZO film and the enhanced binding efficiency of FcCOOH on the IZO film. The results confirm the potential of SIS for the preparation of porous transparent conducting oxide electrodes, which will enable the application of SIS-derived materials in various electrochemical fields.

Solution-processed broadband photodetectors without transparent conductive oxide electrodes

Room-temperature operated photodetectors without transparent conductive oxide electrodes by conjugated polymers mixed with conductive inorganic quantum dots, exhibiting the detectivities over 1012 Jones from 300 nm to 2000 nm, were demonstrated.

Perovskite Solar Cells Go Bifacial-Mutual Benefits for Efficiency and Durability.

Bifacial solar cells hold the potential to achieve a higher power output per unit area than conventional monofacial devices without significantly increasing manufacturing costs. However, efficient bifacial designs are challenging to implement in inorganic thin-film solar cells because of their short carrier lifetimes and high rear surface recombination. The emergence of perovskite photovoltaic (PV) technology creates a golden opportunity to realize efficient bifacial thin-film solar cells, owing to their outstanding optoelectronic properties and unique features of device physics. More importantly, transparent conducting oxide electrodes can prevent electrode corrosion by halide ions, mitigating one major instability issue of the perovskite devices. Here, the theory of bifacial PV devices is summarized and the advantages of bifacial perovskite solar cells, such as high power output, enhanced device durability, and low economic and environmental costs, are reviewed. The limitations and challenges for bifacial perovskite solar cells are also discussed. Finally, the awareness of bifacial solar cells as a feasible commercialization pathway of perovskite PV for mainstream solar power generation and building-integrated PV is advocated and future research directions are suggested.