Simple Surface Treatment Research Articles

Enhanced Plasmonic Electron Transfer from Gold Nanoparticles to TiO2 Nanorods via Electrochemical Surface Reduction

The transport of charge carriers across the heterojunction of an optoelectronic device plays a crucial role in the performance of the device. This issue is particularly important in the area of heterogeneous metal-semiconducting photocatalysis in terms of harvesting the hot carriers generated under plasmonic resonance. This paper presents the results of a case study on the impact of electrochemical surface reduction on the transport properties of plasmonic electrons, which are generated on gold nanoparticles (Au NPs) under visible light irradiation to TiO2 nanorods (TiO2 NRs). Based on microscopic and spectroscopic characterizations, this study examined the subtle changes in the structural and the optical properties of the Au NPs/TiO2 NRs upon surface reduction of the oxygen layer which is ubiquitous on TiO2 NRs. These results suggest that the oxygen layer works as a blocking layer that limits the charge transfer efficiency of plasmonic electrons from Au to TiO2 and, consequently, reduces the device performance. The main thesis was verified directly by comparing the photocatalytic activities of pristine Au NPs/TiO2 NRs and Au NPs/reduced TiO2 NRs with methylene blue as a reference. The photocatalytic performance of the Au NPs/reduced TiO2 NRs was two times higher than that of the pristine one owing to the efficient charge transfer across the Au/TiO2 interface. This simple surface treatment can be employed widely to enhance the charge transport efficiency of various optoelectronic materials and devices derived from metal-semiconducting heterostructures.

Superhydrophobic Shape Memory Polymer Microarrays with Switchable Directional/Antidirectional Droplet Sliding and Optical Performance.

Bioinspired smart surfaces with switchable wettability and optical performance have aroused much attention in the past few years. However, almost all reported surfaces focused on regulating single surface function. In this work, inspired by the butterfly wings, a novel superhydrophobic surface with shape memory polymer microarrays (SMPAs) was prepared through the integration of three-dimensional printing, replica-molding, and a simple surface treatment. In this superhydrophobic SMPA system, the permanent upright microarrays and temporary tilted microarrays can be reversibly switched owing to the excellent shape memory effect (SME). Accompanied by the structure variations, switchable directional/antidirectional droplet sliding and vivid color conversion as the butterfly wings can be achieved. Moreover, because of the SME, local structure regulation can also be achieved on the surface, and with the help of such an ability, the SMPA was further applied as a multifunctional platform to demonstrate controllable droplet transportation and information storage. This work reports the reversible control of directional/antidirectional droplet sliding and tunable color on a superhydrophobic SMPA, and it is believed that such a smart surface can be potentially applied in many fields, such as microfluidic devices and smart optical chips.

Effective Surface Treatment for High-Performance Inverted CsPbI2Br Perovskite Solar Cells with Efficiency of 15.92%

HighlightsA simple and multifunctional surface treatment strategy is proposed to address the inferior-performance inverted CsPbI2Br perovskite solar cells (PSCs).The induced-ions exchange can align energy levels, passivate both GBs and surface, and gift the solid protection from external erosions.The inverted CsPbI2Br PSCs reveal a champion efficiency of 15.92% and superior stability after moisture, operational, and thermal ages.Developing high-efficiency and stable inverted CsPbI2Br perovskite solar cells is vitally urgent for their unique advantages of removing adverse dopants and compatible process with tandem cells in comparison with the regular. However, relatively low opening circuit voltage (Voc) and limited moisture stability have lagged their progress far from the regular. Here, we propose an effective surface treatment strategy with high-temperature FABr treatment to address these issues. The induced ions exchange can not only adjust energy level, but also gift effective passivation. Meanwhile, the gradient distribution of FA+ can accelerate the carriers transport to further suppress bulk recombination. Besides, the Br-rich surface and FA+ substitution can isolate moisture erosions. As a result, the optimized devices show champion efficiency of 15.92% with Voc of 1.223 V. In addition, the tolerance of humidity and operation get significant promotion: maintaining 91.7% efficiency after aged at RH 20% ambient condition for 1300 h and 81.8% via maximum power point tracking at 45 °C for 500 h in N2. Furthermore, the unpackaged devices realize the rare reported air operational stability and, respectively, remain almost efficiency (98.9%) after operated under RH 35% for 600 min and 91.2% under RH 50% for 300 min.Graphic

Laser surface treatment of pure titanium: Microstructural analysis, wear properties, and corrosion behavior of titanium carbide coatings in Hank's physiological solution

Titanium exhibits poor mechanical features such as low hardness and wear resistance. In this research, we considerably enhance the hardness and wear resistance of Ti by a simple laser surface treatment method. Titanium carbide (TiC) structure was successfully generated on Ti samples by means of laser. Vickers hardness indenter, wear test, impedance spectroscopy, and polarization analyses were carried out to scrutinize the mechanical and corrosion properties of samples. Adhesion between Ti and the formed TiC structure is favorite aspect of this method. The results confirmed that the TiC layer improved the mechanical hardness of the Ti. Additionally, the friction coefficient values of laser-treated Ti samples dramatically decreased. The surface roughness of laser-treated Ti declined to its minimum value with increase in laser-treatment time. Although, laser-surface treatment of Ti did not make an evident change in the corrosion resistance of Ti in Hank's physiological solution compared to reference Ti, the escalation of Ti hardness with laser-treatment time is a favorable aspect of this method.

Silver Surface Treatment of Cu(In,Ga)Se2 (CIGS) Thin Film: A New Passivation Process for the CdS/CIGS Heterojunction Interface

The interface engineering of Cu(In,Ga)Se2 (CIGS)‐based solar cells is challenging for high‐efficiency devices, especially for the CdS/CIGS heterojunction interface. Recently, post‐treatment of the CIGS surface, as an efficient approach to passivate the defects at the CdS/CIGS interface, has attracted widespread attention. Here, a simple Ag surface treatment process is used to realize the passivation of interface defects and the enhancement of the CdS/CIGS heterojunction. This process not only reduces the surface roughness of CIGS films significantly, but also contributes to controlling the Ga composition in the surface layer. Furthermore, characterization techniques reveal that Ag surface treatment can effectively decrease the defect concentrations at the heterojunction interface and enhance the CdS/CIGS heterojunction quality with appropriate Ag deposition duration. Further investigations on the changed defect level caused by the Ag surface treatment indicate that the increased defect level is likely related to the shift of valence band maximum. Eventually, the efficiency of the optimum device has a relative increase of about 18% compared with that of the reference solar cell. This work focuses on revealing the differences of the CIGS surface and CdS/CIGS interface caused by Ag, which provides a new surface processing method for the passivation of the CdS/CIGS heterojunction.

Relationship between the hydroxyl termination and band bending at (2¯01)β−Ga2O3 surfaces

Synchrotron x-ray photoelectron spectroscopy was used to explore the relationship between the hydroxyl termination and band bending at the $(\overline{2}01)$ surface of $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{G}{\mathrm{a}}_{2}{\mathrm{O}}_{3}$ bulk single crystals. All as-received $(\overline{2}01)$ surfaces were terminated with OH groups, with H/OH binding to surface ${\mathrm{O}}_{\mathrm{s}}/\mathrm{G}{\mathrm{a}}_{\mathrm{s}}$ atoms. Removal of this native OH termination produced a large upward shift in band bending of up to 1.0 eV, consistent with strong electron depletion and a semiconductor to insulator-like transition in the near-surface region. Simple surface treatments were used to control the size and stability of the band bending of as-received $(\overline{2}01)$ surfaces by modifying the nature of the OH termination. NaOH (${\mathrm{H}}_{2}\mathrm{S}{\mathrm{O}}_{4}$) treatment consistently produced upward (downward) shifts in band bending and a significant increase (decrease) in the thermal stability of the OH termination that was associated with an increase in the relative density of $\mathrm{G}{\mathrm{a}}_{\mathrm{s}}\text{\ensuremath{-}}\mathrm{OH}$ (${\mathrm{O}}_{\mathrm{s}}\text{\ensuremath{-}}\mathrm{H}$) species. Annealing in wet ${\mathrm{O}}_{2}$ (at 600 \ifmmode^\circ\else\textdegree\fi{}C) produced an extremely stable OH termination and the strongest downward shift in band bending. These effects, combined with the relatively slow dissociation of ${\mathrm{H}}_{2}\mathrm{O}$ on bare $(\overline{2}01)$ surfaces, allowed the preparation of surfaces with significant variations in band bending that may prove useful in optimizing the properties of $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{G}{\mathrm{a}}_{2}{\mathrm{O}}_{3}$ metal-semiconductor contacts and heterojunctions. A comparison of two methods used to determine the absolute band bending at semiconductor surfaces confirmed that bare $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{G}{\mathrm{a}}_{2}{\mathrm{O}}_{3}(\overline{2}01)$ surfaces are characterized by strong upward band bending (\ensuremath{\sim}0.5 to 1.0 eV) and an electron depletion layer that can be completely removed by the hydroxylation of the surface.

Self-powered ultraviolet photovoltaic photodetector based on graphene/ZnO heterostructure

Compared to ZnO-based photoconductive photodetectors (PDs), photovoltaic PDs possess the advantages of easy fabrication, low dark current, high response speed and possible self-driven ability. In this paper, an ultraviolet (UV) photovoltaic photodetector based on graphene/ZnO heterostructure was fabricated and investigated. A simple surface treatment was conducted by soaking the as-grown ZnO film in H2O2 solution at room temperature. After this processing, a transition from ohmic contact to Schottky contact was observed in graphene/ZnO interface, accompanied with a high-performance photovoltaic behavior for the graphene/H2O2-treated ZnO (denoted as G/H-ZnO) heterostructure. The self-powered Schottky photodetector of G/H-ZnO exhibits a responsivity of 50 μA/W and a short rise/decay time of 32 ms at zero bias. The fast response performance benefits from the rapid separation of photogenerated carriers, which can be attributed to the synergistic effect of pyroelectric potential and built-in electric field at graphene/ZnO interface. This study provides a facile approach for the development of ZnO-based self-powered photovoltaic devices.

Orientation control of ideal blue phase photonic crystals

Three-dimensional (3D) photonic crystals like Blue Phases, self-assemble in highly organized structures with a sub-micrometer range periodicity, producing selective Bragg reflections in narrow bands. Current fabrication techniques are emerging at a fast pace, however, manufacturing large 3D monocrystals still remains a challenge, and controlling the crystal orientation of large crystals has not yet been achieved. In this work, we prepared ideal 3D Blue Phase macrocrystals with a controlled crystal orientation. We designed a method to obtain large monocrystals at a desired orientation and lattice size (or reflection wavelength) by adjusting the precursor materials formulation and a simple surface treatment. Moreover, using the same method, it is possible to predict unknown lattice orientations of Blue Phases without resorting to Kossel analysis. Producing large 3D photonic crystals that are also functional tunable structures is likely to have a direct impact on new photonic applications, like microcavity lasers, displays, 3D lasers, or biosensors.

Effect of chloride treatment on optical and electrical properties of PbS quantum dots

The relation between surface chemistry and (Opto)electrical properties of lead sulfide quantum dots (PbS QDs) is of importance for the development of cost-effective field-effect transistor (FETs) and quantum dot solar cells. Herein, simple chloride surface treatment has been demonstrated by adding tetramethylammonium chloride (TMACl) into a QD washing step. Absorption, photoluminescence (PL) and X-ray photoelectron spectroscopic studies revealed that Cl− ions bound strongly to PbS QDs surfaces resulting in enhanced PL of colloidal QDs. Furthermore, FET studies on PbS QD thin films fabricated by an identical solid-state ligand exchanging with 1,2-ethanedithiol (EDT) showed that TMACl treatment enhanced hole mobility by ten times and at the same time switched the EDT-treated QD thin film from p-type to ambipolar semiconductor with electron mobility of 2.8 × 10−2 cm2V−1s−1. The results demonstrated herein offer a simple treatment for the fabrication of multiple QD junctions with minor change in processing.

Effect of ozone-treated single-walled carbon nanotubes on interfacial properties and fracture toughness of carbon fiber-reinforced epoxy composites

In this study, superior mechanical properties were obtained for composite materials using single-walled carbon nanotubes (SWCNTs) subjected to a simple surface treatment. The effects of ozone-treatment on the surface properties of the SWCNTs/CFs/epoxy multi-scale composites were investigated in terms of interfacial properties and fracture toughness. The resultant surface free energy after ozone-treated SWCNTs (O-SWCNTs) markedly increased the polar component of the contact angle. In addition, the surface morphology image showed that the surface roughness of O-SWCNTs increased, suggesting that the surface roughness and the number of oxygen functional groups were effectively increased by ozone-treatment. Due to the surface modification, the interlaminar shear strength and fracture toughness of multilayered composites increased by 79.98% and 54.59%, respectively. This shows a direct linear relationship between the morphological changes of O-SWCNTs and the specific polar component of the surface free energy of the material as well as its mechanical properties.

Improved Performance of Acetone Gas Sensing through Oxygen Vacancy Formation of ZnO Nanoparticles

Introduction Recently, interest in gas sensors have been increasing in different fields of not only industry and medical applications but also development of smart city and detection of indoor air pollutants. In particular, acetone is a volatile organic compound (VOC) used as a biomarker to indicate various diseases in human exhalation, or has been importantly measured as one of the indicator gases for indoor pollution measurement [1]. Unlike industrial sensors that need to detect relatively high concentration gas, the detection of acetone for biomarkers requires highly sensitive sensing materials which can react with the gas quickly.Metal oxide semiconductor (MOS) have been widely used as gas sensors because of their thermal and chemical stability and natural abundance. A lot of researches for detecting acetone gas using metal oxide semiconductor, for instance, WO3, SnO2 and ZnO through diverse method and morphology control, have been studied in recent [2]. Among them, ZnO is in the spotlight for various reasons due to their facile size and structure control, gas reactive surface and appropriate band gap. Many papers associated gas sensing of ZnO were published in multiple ways as metal doping and quantum dot control [3, 4]. In this study, oxygen vacancy was produced by simple H2O2 surface treatment of commercial ZnO, and the amount of oxygen vacancy by the degree of surface treatment was quantified. In addition, through evaluating acetone sensing performance according to the amount of oxygen vacancy, optimal vacancy amount showing significantly superior sensitivity was found. Chemical calculation described the reason of the outstanding response [5-8]. Further information will be discussed in detail. Method Surface oxygen vacancy is generated by a variety of H2O2 treatment with 400 ˚C annealing. ZnO controlled oxygen vacancy was reacted with 10 ppm acetone at 300 – 500 ˚C, and confirm response of the material. Response of varied temperature was confirmed through three or more repeated sensor measurements, and the measurement was performed at various concentration ranging from 0.01 ppm to 10 ppm under optimized temperature conditions. And the performance was identified under various humidity conditions and long-term stability. Results and Conclusions When H2O2 was treated on commercial ZnO, ZnO2 was produced. ZnO with oxygen vacancy was formed after 400 ˚C annealing on the obtained ZnO2. Treatment with high concentrated H2O2 results in more defects, breaking crystallinity and reducing the XRD peak sharpness. Therefore, we found optimal concentration conditions that create oxygen vacancy around the surface. The deficient oxygen and lattice oxygen peaks were deconvoluted from the O 1s peaks of the XPS spectrum and the vacancy to lattice ratio was obtained. Also, the formation of oxygen vacancy could be confirmed by the peak shift of Zn 2p3/2. The oxygen vacanced ZnO had a high sensitivity of 1692.1 (Fig. 1). This results showed the world’s best sensitivity compared with previous reported outcomes such as commercial ZnO (S=107), SnO2 nanorod arrays (S=511) and In-doped ZnO quantum dots (S=424). This study shows the possibility of commercialization through a simple surface treatment method that can be widely applied to a wide range of metal oxides, and it is widely applicable to systems of diverse fields where low concentrations of acetone have to be fairly sensitive.

A plausible method of preparing the ideal p-n junction interface of a thermoelectric material by surface doping

Recent advances in two-dimensional (2D) crystals make it possible to realize an ideal interface structure that is required for device applications. Specifically, a p-n junction made of 2D crystals is predicted to exhibit an atomically well-defined interface that will lead to high device performance. Using angle-resolved photoemission spectroscopy, a simple surface treatment was shown to allow the possible formation of such an interface. Ta adsorption on the surface of a p-doped SnSe shifts the valence band maximum towards the higher binding energy due to the charge transfer from Ta to SnSe that is highly localized at the surface due to the layered structure of SnSe. As a result, the charge carriers of the surface are changed from holes of its bulk characteristics to electrons, while the bulk remains as a p-type semiconductor. This observation suggests that the well-defined interface of a p-n junction with an atomically thin n-region is formed between Ta-adsorbed surface and bulk.

Manufacturing aluminum/polybutylene terephthalate direct joints by using hot water–treated aluminum via injection molding

Metal–polymer direct joining helps meeting the growing demand for lightweight design in industry. Injection molded direct joining (IMDJ) is one of the promising metal–polymer direct joining methods. It needs firstly metal surface treatment and then injection insert molding. In this study, we proposed a simple, economical, and eco-friendly surface treatment, named as hot water treatment (HWT) for IMDJ. HWT produces complexed plate-like nanostructures on the aluminum surface. Polymer can flow into nanostructures and produce a mechanical interlocking effect by which metal and polymer achieve direct joining. The HWT treatment conditions, including water temperature and treatment time, were optimized. With the optimized condition, the highest joining strength of 22.5 MPa was obtained. An atomic force microscope (AFM) investigation on nanostructures and tensile shear tests to the joined specimens proved that the joining strength was strongly correlated with the combination of the arithmetical mean height (Sa) and the number of nanostructures (Nn). In addition, the joined specimens also achieved high cycle fatigue. Results showed that high-quality joint can be produced by treating aluminum with HWT. Compared with conventional chemical surface treatment methods, HWT is much easier to apply in practices. Wide applications in industries can be expected.

Enhanced interfacial strength of hierarchical fiberglass composites through an aramid nanofiber interphase

Interfacial adhesion in fiber reinforced composites is a critical factor for their mechanical performance in structural applications. As nanomaterials continue to rise in prominence, the use of nanostructured interphases has grown to become a viable technique to reinforce the fiber-matrix interface of fiber reinforced polymer composites. Here, a polymeric interphase consisting of aramid nanofibers (ANFs) is introduced on Poly(diallyldimethylammonium chloride) (PDDA) coated fiberglass through electrostatic adsorption. The simple and rapid coating technique considerably roughens the inorganic fiber surface, while enriching it with polar functional groups that are capable of chemically bonding with the matrix, all while preserving the structural integrity of the fiber. The nanostructured coating improves the interfacial shear strength by up to 83.2%, along with a 35.3% improvement in short beam shear strength. These improvements can be attributed to the enhanced chemical and mechanical interactions between the fiber and the matrix. The following findings highlight the potential for the utilization of a PDDA coating to enhance the adhesion of ANFs on fiberglass and enable the fabrication of composite structures with higher strength and toughness through a rapid, simple and effective surface treatment.

Tailored Amphiphilic Molecular Mitigators for Stable Perovskite Solar Cells with 23.5% Efficiency.

Passivation of interfacial defects serves as an effective means to realize highly efficient and stable perovskite solar cells (PSCs). However, most molecular modulators currently used to mitigate such defects form poorly conductive aggregates at the perovskite interface with the charge collection layer, impeding the extraction of photogenerated charge carriers. Here, a judiciously engineered passivator, 4-tert-butyl-benzylammonium iodide (tBBAI), is introduced, whose bulky tert-butyl groups prevent the unwanted aggregation by steric repulsion. It is found that simple surface treatment with tBBAI significantly accelerates the charge extraction from the perovskite into the spiro-OMeTAD hole-transporter, while retarding the nonradiative charge carrier recombination. This boosts the power conversion efficiency (PCE) of the PSC from ≈20% to 23.5% reducing the hysteresis to barely detectable levels. Importantly, the tBBAI treatment raises the fill factor from 0.75 to the very high value of 0.82, which concurs with a decrease in the ideality factor from 1.72 to 1.34, confirming the suppression of radiation-less carrier recombination. The tert-butyl group also provides a hydrophobic umbrella protecting the perovskite film from attack by ambient moisture. As a result, the PSCs show excellent operational stability retaining over 95% of their initial PCE after 500 h full-sun illumination under maximum-power-point tracking under continuous simulated solar irradiation.

On the importance of light scattering for high performances nanostructured antireflective surfaces

An antireflective coating presenting a continuous refractive index gradient is theoretically better than its discrete counterpart because it can give rise to a perfect broadband transparency. This kind of surface treatment can be obtained with nanostructures like moth-eye. Despite the light scattering behavior must be accounted as it can lead to a significant transmittance drop, no methods are actually available to anticipate scattering losses in such nanostructured antireflective coatings. To overcome this current limitation, we present here an original way to simulate the scattering losses in these systems and routes to optimize the transparency. This method, which was validated by a comparative study of coatings presenting refractive indices with either discrete or continuous gradient, shows that a discrete antireflective coating bilayer made by oblique angle deposition allows reaching ultra-high mean transmittance of 98.97% over the broadband [400–1800] nm. Such simple surface treatment outperforms moth-eye architectures thanks to both interference effect and small dimensions nanostructures that minimize the scattering losses as confirmed by finite-difference time domain simulations performed on reconstructed volumes obtained from electron tomography experiments.

Bifunctional Passivation Strategy to Achieve Stable CsPbBr3 Nanocrystals with Drastically Reduced Thermal-Quenching.

The thermal quenching behavior (temperature-dependent luminescence) has severely hindered the practical applications of CsPbX3 nanocrystals. Here, we find that a simple surface treatment using ammonium hexafluorosilicate (AHFS, (NH4)2SiF6) can drastically reduce the thermal quenchingof CsPbBr3 nanocrystals (CPB-NCs) while enhancing their photostability. The AHFS-treated sample sustains 90% of its original emission intensity as the temperature rises to 353 K, which is much better than that (17%) of the pristine sample. Meanwhile, the thermally stable AHFS-treated sample could maintain 93% of its initial PL emission after a 450 nm LED illumination of 53 h. Structural and surface characterizations indicate that the hydrolyzable AHFS absorbed on the surface could lead to a bifunctional passivation for CPB-NCs, through fluoride ions and its hydrolyzed product of silica, which can reduce the thermal quenching by limiting thermally activated carriers trapping into vacancies and block the attack from external environmental factors.

Efficient lateral-structure perovskite single crystal solar cells with high operational stability

The power conversion efficiency of perovskite polycrystalline thin film solar cells has rapidly increased in recent years, while the stability still lags behind due to its low thermal stability as well as the fast ion migration along the massive grain boundaries. Here, stable and efficient lateral-structure perovskite solar cells (PSCs) are achieved based on perovskite single crystals. By optimizing anode contact with a simple surface treatment, the open circuit voltage and fill factor dramatically increase and promote the efficiency of the devices exceeding 11% (0.05 to 1 Sun) compared to that of 5.9% (0.25 Sun) of the best lateral-structure single crystal PSCs previously reported. Devices show excellent operational stability and no degradation observed after 200 h continuous operation at maximum power point under 1 Sun illumination. Devices with scalable architectures are investigated by utilizing interdigital electrodes, which show huge potential to realize low cost and highly efficient perovskite photovoltaic devices.

Surface Treatment on Nickel Oxide to Enhance the Efficiency of Inverted Perovskite Solar Cells

The organic-inorganic hybrid perovskites such as CH3NH3PbI3 have been considered as one of the most promising candidates for the next-generation photovoltaic materials due to its high absorption coefficient, low exciton binding energy, and long diffusion length. Herein, we have chosen NiOx as the hole transport material because metal oxides exhibit robust properties in air. We synthesized the NiOx film by a common sol-gel method. It is found that high-temperature annealing (500°C) is required to ensure the perovskite solar cell (PSC) with an efficiency over 15%. Low-temperature annealing (100°C) cannot convert the precursor materials to fully covered NiOx film, while the PSC based on mediate-temperature annealing (300°C) NiOx has larger resistance and thus lower efficiency. Fortunately, we have found that UV-ozone treatment on the NiOx film can reduce the resistance of the device based on 300°C annealed NiOx. The champion device can reach 16% efficiency with UV-ozone-treated 300°C annealed NiOx. This work has made it possible to reduce the annealing temperature of the sol-gel NiOx for high-efficiency PSCs, and it is believed that this simple surface treatment can be further employed in other metal oxide-based optoelectronic devices.

Roughness-enhanced collection of condensed droplets.

Gravity shedding of droplets is limited by droplet pinning, a major limitation for low condensation processes and in particular passive dew harvesting in its use as an alternative source of water. We present experiments showing that, paradoxically, a simple surface treatment increasing roughness (sand-blasting) favors droplet shedding compared to the original substrate, provided that sand-blasting does not increase too much the surface roughness. Sand-blasting ensures the high density of nucleation sites and enhances drops coalescence and growth at a sub-micron scale, thus lowering the lag-time to obtain drop sliding during condensation. Early nucleation indeed overcompensates the delay increase due to roughness. Edges of the substrate, where drops grow faster, also improve water collection, thanks to the early sliding of edge drops that behave as natural wipers. Combining the effects of sand-blasting and edges increases significantly the rate of collection of dew condensation on a substrate at a given time, gains of about 30% can be commonly obtained.