Low-temperature Chemical Bath Deposition Research Articles

Synthesis and Characterization of ZnO/Cu<sub>2</sub>O and Co co-doped Ag-ZnO/Cu<sub>2</sub>O Nanoparticles with Possible Photovoltaic Applications

The Photovoltaics phenomenon is one of the major turning points in the battle against the depletion of fossil fuels. Sunlight is the main resource in photovoltaics, but there remains a quest to harvest it efficiently to generate electricity. This study is focused on designing basic, cost-effective prototype solar cells using ZnO/Cu2O nanoparticles (NPs) and Co(cobalt) co-doped Ag-ZnO/Cu2O NPs under normal university laboratory conditions. ITO-coated glass was used as the substrate of the solar cell and a modified low-temperature chemical bath deposition method was used for fabrication. Both ZnO and Cu2O NPs were synthesized by aqueous precipitation methods and the fabrication was performed successfully using ZnO and Cu2O NPs. However, the fabrication with Co co-doped Ag-ZnO and Cu2O NPs requires more research since the Co co-doped Ag-ZnO NPs were synthesized by solvothermal method, and it appeared as a fine powder which was not thick enough to hold onto the Cu2O layer. The UV-spectroscopic analysis confirmed the characteristic band of ZnO NPs at 367.5 nm, Cu2O NPs at 360 nm, and Co co-doped Ag-ZnO NPs at 378 nm. The FTIR spectrum showed sharp peaks at 460 cm-1 and 606 cm-1 for the corresponding Zn-O bond and Cu-O bond, respectively with a broad peak at 1329 cm-1 for Cu2O FTIR, due to the chemisorbed and/or physiosorbed H2O and CO2 molecules on the surface of the nanostructure. The EDX analysis showed the presence of slight carbon impurity in ZnO NPs which resulted in a deviated XRD pattern while Cu2O NPs showed the characteristic XRD pattern. The solar cell illuminated under three different lux conditions, had the characteristic J-V plot when measured through Gamry Potentiostat.

Interfacial competing interaction eliminates voids in the buried interface for efficient and stable perovskite solar modules on bare NiOX

Perovskite solar cells (PSCs) with impressive efficiency is promising for commercialization. However, when scaling up PSCs to large-area perovskite solar modules (PSMs), the rapid degradation of performance and stability still remains a grand challenge. One of the main causes of the degradation is the presence of local voids in the buried interface for large-area films, which we find could be attributed to the unbalanced interfacial interaction between precursor solvent and substrate. Here we improve a scalable and low-temperature sequential two-step chemical bath deposition process aiming for high quality NiOX. Further with the modulation of A-site cations to enhance the interaction between DMSO and perovskite precursor, the potential for DMSO absorbing on the NiOX could be eliminated. This strategy can inhibit the delay movement of DMSO on NiOX and improve the buried interfacial quality, with compact morphology and absent of voids. The inverted structured PSCs and PSMs based on the bare NiOX and modified perovskite precursor reach a champion efficiency of 22.40% and 19.09%, respectively, which are both among the highest reported values. The highly efficient PSMs also exhibit a long-term operational stability, which retain 84% of the initial performance after 1056 h operating under one-sun illumination.

Cathodized Stainless Steel Mesh for Binder-Free NiFe<sub>2</sub>O<sub>4</sub>/NiFe Layer Double Hydroxides Oxygen Evolution Reaction Electrode

Oxygen evolution reaction (OER) is an essential reaction commonly applied in various energy storage and conversion technologies. One of the common issues of OER lies in its low kinetic activity. Therefore, developing durable, low-cost, and high-performance OER catalysts is critical. Recently, many attempts have used stainless steel mesh (SSM) as the substrate for OER electrodes because SSM is abundant, cheap, and durable. Nickel/iron-based materials, i.e., NiFe2O4/NiFe layer double hydroxides (LDHs), are regarded as one of the most excellent OER catalysts in alkaline electrolytes, making them attractive low-cost materials for OER catalysts. However, synthesizing NiFe2O4/NiFe LDHs directly on the surface of SSM is challenging. Modifying the SSM surface through cathodization has proved to enhance the adhesion and OER activity. Moreover, the cathodization technique is facile and cost-effective. In this work, the surface of SSM is modified by cathodization treatment. Subsequently, NiFe2O4/NiFe LDHs are deposited onto the surface of treated SSM via a low-temperature one-step chemical bath deposition technique. This synthesis is a binder-free method; the resulted electrodes show excellent OER performance without the binder effects. The as-prepared electrodes have a small Tafel slope of 125.4 mV/dec (1 M KOH) and high durability (10 mA/cm2 for 50 hours).

Synthesis of Template-free Flower-like ZnO Nanorods using a Simple Chemical Bath Technique

Flower-like ZnO nanorods were successfully synthesised using a template-free, low-temperature chemical bath deposition method. The effects of growth time on the structural, morphological, and vibrational properties of flower-like zinc oxide were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that the crystallite size and density of flower-like ZnO nanorods increased with increasing growth time. Raman spectroscopy confirmed the existence of specific Raman modes that correspond to the wurtzite structure of ZnO. In addition, Raman measurements revealed that increased growth time increases the Raman modes intensity of the flower-like ZnO nanorods. Moreover, the measurements of the Au/ZnO nanorods/FTO Schottky diode showed that all devices functioned as Schottky diodes and rectifying; however, their ideality factor was greater than 1. In addition to the ideality factor, the Schottky barrier height was calculated and slightly increased with growth time. The values of Schottky barrier height obtained were 0.502 eV, 0.523 eV, 0.516 eV and 0.529 eV for samples grown at 1, 2, 3 and 4 h, respectively.

PbS/p‐Si NW Heterojunction Thin Film Device for Room Temperature NH3 Detection

AbstractOne dimensional heterostructures with a definite interface where the host particle is decorated with the secondary material have been widely exploited for photocatalysis because of increased efficiency. Herein we report the synthesis of PbS−Si NW heterojunction using low temperature chemical bath deposition (CBD) techniques. Temperature, time, and the complexing agents of the growth solution were optimized to control the morphology and the resultant properties of the heterojunction thin films. These synthesized thin films exhibit high sensor responses in the presence of ammonia (NH3) due to an increase in the surface area and efficient p‐n junction formation. Additionally, there is a vast improvement in the detection limit of the sensors as our device was found to respond at concentrations as low as 0.1 ppm. Growth conditions are found to have significant influence on the sensor response.

Low-Temperature Chemical Bath Deposition of Conformal and Compact NiOX for Scalable and Efficient Perovskite Solar Modules.

A scalable and low-cost deposition of high-quality charge transport layers and photoactive perovskite layers are the grand challenges for large-area and efficient perovskite solar modules and tandem cells. An inverted structure with an inorganic hole transport layer is expected for long-term stability. Among various hole transport materials, nickel oxide has been investigated for highly efficient and stable perovskite solar cells. However, the reported deposition methods are either difficult for large-scale conformal deposition or require a high vacuum process. Chemical bath deposition is supposed to realize a uniform, conformal, and scalable coating by a solution process. However, the conventional chemical bath deposition requires a high annealing temperature of over 400 °C. In this work, an amino-alcohol ligand-based controllable release and deposition of NiOX using chemical bath deposition with a low calcining temperature of 270 °C is developed. The uniform and conformal in-situ growth precursive films can be adjusted by tuning the ligand structure. The inverted structured perovskite solar cells and large-area solar modules reached a champion PCE of 22.03% and 19.03%, respectively. This study paves an efficient, low-temperature, and scalable chemical bath deposition route for large-area NiOX thin films for the scalable fabrication of highly efficient perovskite solar modules.

A Low-Cost Resilient Chalcogenide Ion-Sensitive Electrode for Copper Sensing With an LoD $< $20 ppb

A solid-state ion-sensitive electrode for the monitoring of copper metal ions in water based on a CdS chalcogenide thin film is fabricated using a low-temperature process. This sensor exhibits a limit of detection of 18.7 ppb. A sensing layer consisting of a chalcogenide material was deposited over a conducting substrate using a low-temperature chemical bath deposition process. Electrochemical impedance spectroscopy and potentiometric measurements were carried out to analyze the response of the sensing layer to the copper ions in water samples. The sensor yields a monotonic response in the concentration range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${1\times 10^{-3}}$</tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${1\times 10^{-7}}\ \mathrm{M}$</tex-math></inline-formula> with a response time of a few seconds. The resulting sensor is compatible with large-area fabrication techniques on flexible substrates.

Efficiency improvement of perovskite solar cells by charge transport balancing using length tunable ZnO nanorods and optimized perovskite morphology

Well-aligned ZnO nanorods with tunable length are successfully deposited using a low-temperature chemical bath deposition method, and subsequently used in constructing solar cells with the structure of FTO/ZnO nanorods/MAPbI 3-x Cl x /P3HT/Au. The charge transport is balanced by tuning the length of nanorods and improving the morphology of the perovskite layer. Uniformity and charge transport within the film is improved by doping the perovskite structure with Cl − ions. The photovoltaic characteristics of the cells are improved as the length of nanorods increases from 300 nm to 460 nm, and deteriorate as it increases further. Using nanorods with the length of 460 nm, power conversion efficiency of 12.85% and J sc over 22 mA/cm 2 are obtained. This efficiency is in the range of the best efficiencies reported so far using P3HT as the hole transporting layer (HTL) and ZnO as the electron transporting layer (ETL). For the first time, PSCs based on ZnO nanorods are fabricated, in which copper iodide is deposited as the inorganic HTL through vapor iodination of Cu film. A promising efficiency of 8.09% is achived which is in the range of the highest efficiencies reported for n-i-p PSCs with CuI as the HTL. • Charge transport was balanced by tuning the length of ZnO nanorods and improving their morphology. • P3HT was used as an effective, relatively inexpensive, hydrophobic hole transport layer. • The Morphology was improved by using Cl ions doping and solvent engineering. • Open circuit voltage and fill factor of the cells were found to both depend on the length of ZnO nanorods (layer thickness). • For the first time, using CuI as the hole transport layer, all-inorganic PSC based on ZnO nanorods was fabricated.

CBD grown pure and Ce-doped ZnO nanorods: Comparison of their photocatalytic degrading efficiencies on AR88 azo dye under visible light irradiation

A seed-mediated approach was utilized in growing of pure and cerium-doped ZnO nanorods via a low-temperature (∼95 °C) chemical bath deposition (CBD) method. The aqueous solutions with different Ce molar ratios (Ce/(Ce + Zn), which were equal to 0, 0.01, 0.05, 0.1 or 0.2) were prepared. An excess amount of cerium ions (≥0.1 in the present study) caused the formation of a new phase, identified as CeO2. Cerium doping induces lattice strains due to the difference in radius of the anions. With doping, the 2θ angle of X-ray diffraction (XRD) peaks slightly shifted towards lower values. Inserting cerium atoms brings about decrease, as well, in the band gap, which was confirmed by the redshifts at the absorption edges in their UV–vis spectra. In addition, the photoluminescence (PL) spectra of the samples were measured at room temperature revealed the enhanced visible emission intensities from the Ce-doped nanorods. This indicates the formation of defect levels below the conduction band. Finally, the photocatalytic degrading efficiencies of the samples on Acid Red 88 (AR88) azo dye were determined under visible light irradiation. The highest degradation rate was measured for the doped samples prepared using the CBD solution with the Ce/(Ce + Zn) ratio equal to 0.01.

Defects-free single-crystalline zinc oxide nanostructures for efficient photoelectrochemical solar hydrogen generation

The article reports a novel and highly efficient methodology for the development of surface defects-free zinc oxide (ZnO) nanostructures, which are highly useful for various optoelectronic and electronic devices. Using this approach, we have developed high-quality ZnO nanostructures with comparable physical and chemical properties to high-temperature grown ones. Initially, ZnO nanostructures were developed by low-temperature chemical bath deposition, and the surface defects passivated structures were obtained by atomic layer deposition of homo-molecular clusters, i.e., Zn and O atomic layers. The surface passivated ZnO nanostructures exhibited excellent chemical stoichiometry between their constituents with enhanced crystalline quality. These nanostructures also showed improved light transmittance in the wavelengths range of 450–1000 nm, and light emission in the ultraviolet region. Further, the surface passivated nanostructures exhibited remarkable device performance as photoanodes with a greatly improved photocurrent density, more than 3 times, and reduced cathodic current of 6.17 × 10−7 A@-0.4 V. Significantly, the light-to-dark current ratio of the PEC devices fabricated with passivated ZnO nanostructures is found to be 1761.

Facile, wafer-scale compatible growth of ZnO nanowires via chemical bath deposition: assessment of zinc ion contribution and other limiting factors.

ZnO is a highly promising, multifunctional nanomaterial having various versatile applications in the fields of sensors, optoelectronics, photovoltaics, photocatalysts and water purification. However, the real challenge lies in producing large scale, well-aligned, highly reproducible ZnO nanowires (NWs) using low cost techniques. This large-scale production of ZnO NWs has stunted the development and practical usage of these NWs in fast rising fields such as photocatalysis or in photovoltaic applications. The present article shows an effective, simple approach for the uniform, aligned growth of ZnO NWs on entire silicon wafers (sizes 3 or 4 inches), using a low-temperature Chemical Bath Deposition (CBD) technique. In addition to this, a systematic study of the substrate size dependent growth of NWs has been conducted to better understand the effect of the limitation in the deposition rate of Zn2+ ions on the growth of NWs. The growth rate of ZnO NWs is seen to have a strong relationship with the substrate size. Also, the loading efficiency of the Zn2+ ions is higher in ZnO NWs grown on a 3-inch silicon wafer in comparison to those grown on a small piece. An in-depth time dependent growth study conducted on entire 3-inch wafers to track the morphological evolution (length, diameter and number of the NWs) reveals that the growth rate of the length of the NWs reaches a saturation state in a short time span of 20 min. Assessment of the overall homogeneity of the NWs grown on the 3-inch wafer and simultaneous growth on two entire 4-inch silicon wafers has also been demonstrated in this article. This demonstration of large-scale, well-aligned controllable, aligned growth of ZnO NWs on entire silicon wafers is a first step towards NW based devices especially for applications such as photovoltaic, water purification, photocatalysis or biomedical applications.

Enhanced photoluminescence effects in nanostructured cubic CdS matrix doped with Cu2+ obtained by chemical Bath deposition

In the present work, we highlight the enhancements of the photoluminescent properties of the binary II-VI nanocomposite thin film semiconductor cadmium sulphide (CdS) doped with the metallic ions Cu2+ obtained by low-temperature chemical bath deposition (CBD). The doping percentage of the CdS matrix was around 1.74% determined by X-ray fluorescence spectroscopy. The most intense photo-electronic transitions of Cd 3d5/2 (404.94 eV), S 2p3/2 (161.52 eV) and Cu 2p3/2 (933.27 eV) were detected by X-ray photoelectron spectroscopy. The crystallographic study shows that the preferential growth planes are cubic (111) both in the matrix and the doped samples. HRTEM micrographs exhibit the reduction of the particle size of the CdS matrix from 5.87 to 4.76 nm in the doped sample, which confirms the quantum confinement effect. The first optical effect of the doped CdS was noticed in Raman spectroscopy by a frequency shift of the first longitudinal optical mode (1LO-CdS) from 306 to 302 cm−1, related with the shrinking of the nanoparticle, also a great improvement in the sensibility of the characterization by the surface effects of the Cu2+ metallic ion. Photoluminescence was measured in the temperature range of 258–298 K, which showed more recombination emissions of energetic excitons as consequence of the decrease in particle size and the defects created by the Cu2+ metallic ion in the doped sample in whole the range of investigated temperatures. Also the pronounced stimulation of the luminescent spectra of the semiconductor compound at room temperature.

On the origin of the enhancement of defect related visible emission in annealed ZnO micropods

We report an in-depth analysis of ZnO micropods emission. A strong correlation between defect and interband emissions is observed. ZnO micropods were grown using low-temperature chemical bath deposition (CBD). ZnO micropods exhibited perfectly-crystalline hexagonally-shaped facets with various numbers of branches. Raman studies showed that ZnO micropods contained trapped zinc hydroxide (OH) and imidogen (NH) defects that originate from the precursor solution used in the CBD technique. These defects were evacuated by thermal annealing, leading to the recrystallization in the volume of the micropods and the formation of structural defects at their surface, as attested by scanning electron microscopy and X-ray diffraction. More importantly, the thermal annealing was accompanied by a breakdown of the NH defects, which resulted in a nitrogen doping of the ZnO micropods. The structural changes as well as the nitrogen doping resulted in a drastic change in the photoluminescence (PL) spectrum of the ZnO micropods that exhibited a stronger free exciton UV emission as well as a stronger visible (white) emission. An in-depth low-temperature PL study of both UV and visible emission reveals a strong interplay between the structural-defect bound excitonic UV emission (Y-band) and the deep donor (visible) emission, which suggests a rather complex emission mechanism involving an efficient nonradiative energy transfer between the Y-band states and defect states leading to the enhanced visible emission of ZnO micropods after high temperature annealing.

Combinatorial Tuning of Structural and Optoelectronic Properties in CuxZn1−xS

Summary P-type transparent conductors (TCs) are important enabling materials for optoelectronics and photovoltaics, but their performance still lags behind n-type counterparts. Recently, semiconductor CuxZn1−xS has demonstrated potential as a p-type TC, but it remains unclear how properties vary with composition. Here, we investigate CuxZn1−xS across the entire alloy space (0 ≤ x ≤ 1) using combinatorial sputtering and high-throughput characterization. First, we find a metastable wurtzite alloy at an intermediate composition between cubic endpoint compounds, contrasting with solid solutions or cubic composites (ZnS:CuyS) from the literature. Second, structural transformations correlate with shifts in hole conductivity and absorption; specifically, conductivity increases at the wurtzite phase transformation (x ≈ 0.19). Third, conductivity and optical transparency are optimized within a "TC regime" of 0.10

Doping Efficiency in Cobalt-Doped ZnO Nanostructured Materials

Nanostructured ZnO thin films doped with cobalt from 5% to 20% were grown on glass substrates by a low-temperature chemical bath deposition (CBD) technique. We compared the doping efficiency of incorporating cobalt in ZnO nanostructured samples doped with cobalt via cobalt nitrate and cobalt chloride. The concentration of cobalt incorporated into the ZnO matrix was precisely determined using inductively coupled plasma mass spectroscopy (ICP-MS). Scanning electron microscopy (SEM) images showed that only at a 0.1 M ratio of the precursor solutions in CBD using cobalt nitrate as a dopant, the morphology of ZnO yielded hexagonally shaped nanorods. At a 1 M ratio of the precursor solutions, SEM images showed that the morphology of ZnO was nanoplatelets at all doping levels, irrespective of the doping method used. The synthesized nanostructures retained the wurtzite hexagonal structure only at 0.1 M precursor solution using cobalt nitrate doping, which was confirmed by X-ray diffraction (XRD) studies. In cobalt-doped samples using cobalt chloride as a dopant, XRD analysis confirmed the formation of a Simonkolleite structure. At 300°C, the Simonkolleite structure was converted to a wurtzite structure without changing the morphology. Electrical conductivity measurements at 300 K showed that ZnO nanorods doped with cobalt using cobalt nitrate yielded the lowest resistivity. The molarity of the precursor solution and dopant was found to have a substantial impact on the morphology and doping efficiency of the ZnO nanostructures.

Highly efficient semitransparent CsPbIBr2 perovskite solar cells via low-temperature processed In2S3 as electron-transport-layer

Inorganic perovskite solar cells (IPSCs) with CsPbIBr2 as the light harvester have attracted tremendous attention owing to its thermal stability, low cost and facile manufacture, where electron transport layer (ETL) plays indispensable roles of charge separation, electron transportation and hole-blocking. Although TiO2 is widely used as an ETL, its high-temperature fabrication and low electron mobility hinder the performance and application of IPSCs. Herein, we have proposed a low-temperature (70 °C) chemical bath deposition (CBD) method with different time to prepare In2S3 films as the ETL of IPSCs. By regulating the deposition time of In2S3 films to 85 min, our best-performing device has obtained a high PCE of 5.59% with reduced hysteresis, which is a relative high efficiency for CsPbIBr2 IPSCs by low-temperature fabrication at present. However, the TiO2-based device shows a low efficiency of 5.02% and serious hysteresis. Meanwhile, the In2S3-based devices exhibit improved stability under ambient conditions without encapsulation. Experimental results precisely clarify that this enhanced photovoltaic performance is attributed to the suitable band alignment, low resistance, low recombination of photo-generated carriers at the interface of ETL/perovskite. Promisingly, our low temperature fabricated perovskite and ETL layers might broaden new insights for solution-processed flexible devices.

First report on solution processed α-Ce2S3 rectangular microrods: An efficient energy storage supercapacitive electrode

Rectangular shaped α-Ce2S3 microrods have been grown with the aid of a facile, efficient, low cost and low temperature chemical bath deposition (CBD) approach in thin film form. Characterizations of α-Ce2S3 have been performed through structural, morphological and surface wettability studies. Intermixed rectangular microrods with lower contact angle provide a reduction in intrinsic resistance and effective ion diffusion path during electrochemical activities ensuring maximum utilization of the active electrode species. This leads to achieve a remarkable specific capacitance of 726 F/g at 2 mV/s scan rate with the excellent electrochemical stability of 93% at 2000 CV cycles. Efficient electrochemical findings exhibit excellent scope of α-Ce2S3 towards next-generation energy storage devices.

A simple synthesis of transparent and highly conducting p-type Cu x Al1-x S y nanocomposite thin films as the hole transporting layer for organic solar cells.

Inorganic p-type films with high mobility are very important for opto-electronic applications. It is very difficult to synthesize p-type films with a wider, tunable band gap energy and suitable band energy levels. In this research, p-type copper aluminum sulfide (CuxAl1−xSy) films with tunable optical band gap, carrier density, hole mobility and conductivity were first synthesized using a simple, low cost and low temperature chemical bath deposition method. These in situ fabricated CuxAl1−xSy films were deposited at 60 °C using an aqueous solution of copper(ii) chloride dihydrate (CuCl2·2H2O), aluminium nitrate nonohydrate [Al(NO3)3·9H2O], thiourea [(NH2)2CS], and ammonium hydroxide, with citric acid as the complexing agent. Upon varying the ratio of the precursor, the band gap of the CuxAl1−xSy films can be tuned from 2.63 eV to 4.01 eV. The highest hole mobility obtained was 1.52 cm2 V−1 s−1 and the best conductivity obtained was 546 S cm−1. The CuxAl1−xSy films were used as a hole transporting layer (HTL) in organic solar cells (OSCs), and a good performance of the OSCs was demonstrated using the CuxAl1−xSy films as the HTL. These results demonstrate the remarkable potential of CuxAl1−xSy as hole transport material for opto-electronic devices.

Synthesis and morphological study of Mn doped ZnS films

Low temperature chemical bath deposition (CBD) technique has been employed to synthesize Manganese (Mn) doped ZnS films. The synthesized material was systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL) techniques. XRD spectra revealed the existence of cubic zinc blande structure and nanocrystalline nature of synthesized material. PL spectra shows an intense band at 486 nm (2.55 eV), while the intensity of band obtained at lower energy region 375, 416 nm were decreased in the synthesized film, which indicate that incorporation of Mn decreased the surface defect in ZnS films. Surface structure of Mn doped ZnS nanoparticle was confirmed by FTIR. SEM images depicted the spherical shaped particles evenly distributed throughout the substrate. It was noticed that presence of Mn enhances the agglomeration process, resulting the larger sized particles.

Hierarchical Ag/TiO2/Si Forest-Like Nano/Micro-Architectures as Antireflective, Plasmonic Photocatalytic, and Self-Cleaning Coatings

We report the fabrication of hierarchical silver/titanium dioxide/silicon (Ag/TiO2/Si) structures with forest-like nano/micro-architectures, and their physical (i.e., structural and optical) properties, surface wettability, and photocatalytic activities are studied. The TiO2 nanorods (NRs) are grown on micropyramidal Si (MP-Si) substrates by a facile and low-temperature chemical bath deposition technique. To obtain the optimum structure with low reflectivity, we systematically investigate the optical properties by varying the growth conditions of TiO2-NRs, such as chemical concentrations, growth temperature, and growth time. The optimized TiO2-NRs/MP-Si exhibit efficient antireflective characteristics, indicating the much lower average reflectance (Ravg) and solar weighted reflectance (Rsw) values of ∼3.5% and ∼3.3%, respectively, in a broad wavelength range of 300–1000 nm compared to the bare Si and the MP-Si (i.e., Ravg/Rsw ∼ 41.5%/39.2% and 25.6%/24%). Furthermore, TiO2-NRs/MP-Si show a superhydrophili...