Superior Optical Properties Research Articles

Lead-Free Perovskite Cs3Bi2I9-Derived Electroactive PVDF Composite-Based Piezoelectric Nanogenerators for Physiological Signal Monitoring and Piezo-Phototronic-Aided Strain Modulated Photodetectors.

In recent years, lead-free perovskite materials are exponentially emerging in photovoltaic and optoelectronic applications due to their low toxicity and superior optical properties. On the other hand, the demand for flexible, wearable, and lightweight optoelectronic devices is significantly growing in sensor and actuator technologies. In this scenario, lead-free perovskite-based flexible piezoelectric polymer composites have sparked considerable attention in this field due to their excellent piezo-, pyro-, ferroelectric, and photovoltaic properties. Thus, in this work, a long-term stable lead-free Cs3Bi2I9-PVDF composite is introduced. The in situ growth of the Cs3Bi2I9 perovskite induces 92% yield of the electroactive phase in the PVDF matrix. The possible mechanism behind the electroactive β-phase transformation is presented via interfacial interactions of PVDF moieties with the Cs3Bi2I9 (CBI) perovskite, which also give rise to long-term environmental stability. Next, a piezoelectric nanogenerator (PNG) has been fabricated with the Cs3Bi2I9-PVDF composite for mechanical energy harvesting, biophysiological motion monitoring, and voice recognitions that have potential utility in the health-care sector. Furthermore, a photodetector is developed to realize the piezo-phototronic effect. It exhibits a fast photoswitching behavior with rise and decay times of 141 and 278 ms, respectively. Thus, it is confirmed that the flexible Cs3Bi2I9-PVDF composite has shown tremendous potential to be used as an optical signal-modulated piezo-responsive wearable sensor.

Preparation of tellurium nanowires and its application in ultrafast photonics

As a kind of semiconductors, tellurium has attracted much attention due to its superior optical, electrical, and thermoelectric properties. In particular, a lot of research on low-dimensional tellurium has been performed in recent years, but with relatively few work on its applications in ultrafast photonics. In this work, a femtosecond fiber laser was realized using the prepared tellurium nanowires as the saturable absorber. Tellurium nanowires were synthesized by the hydrothermal method and then deposited on the tapered optical fiber to form the tellurium saturable absorber (Te-SA). The saturable absorption property of Te-SA was tested by the two-arm balance detection method, the saturation intensity and modulation depth were determined to be 8.9 MW/cm2 and 27.0%, respectively. Then, Te-SA was applied in the erbium-doped fiber laser and a stable mode-locked fiber laser with a pulse width of 621 fs was achieved. The results indicate the great potential application of tellurium nanowires in ultrafast photonics.

Ligand Engineering and Recrystallization of Perovskite Quantum-Dot Thin Film for Low-Threshold Plasmonic Lattice Laser.

Solution-process perovskite quantum dots (QDs) are promising materials to be utilized in photovoltaics and photonics with their superior optical properties. Advancements in top-down nanofabrication for perovskite are thus important for practical photonic and plasmonic devices. However, different from the chemically synthesized nano/micro-structures that show high quality and low surface roughness, the perovskite QD thin film prepared by spin-coating or the drop-casting process shows a large roughness and inhomogeneity. Low-roughness and low-optical loss perovskite QD thin film is highly desired for photonic and optoelectronic devices. Here, this work presents a pressure-assisted ligand engineering/recrystallization process for high-quality and well-thickness controlled CsPbBr3 QD film and demonstrates a low-threshold and single-mode plasmonic lattice laser. A recrystallization process is proposed to prepare the QD film with a low roughness (RMS = 1.3nm) and small thickness (100nm). Due to the low scattering loss and strong interaction between gain media and plasmonic nanoparticles, a low lasing threshold of 16.9 µJ cm-2 is achieved. It is believed that this work is not only important to the plasmonic laser field but also provides a promising and general nanofabrication method of solution-processed QDs for various photonic and plasmonic devices.

Transition metal dichalcogenide nanospheres for high-refractive-index nanophotonics and biomedical theranostics

Recent developments in the area of resonant dielectric nanostructures have created attractive opportunities for concentrating and manipulating light at the nanoscale and the establishment of the new exciting field of all-dielectric nanophotonics. Transition metal dichalcogenides (TMDCs) with nanopatterned surfaces are especially promising for these tasks. Still, the fabrication of these structures requires sophisticated lithographic processes, drastically complicating application prospects. To bridge this gap and broaden the application scope of TMDC nanomaterials, we report here femtosecond laser-ablative fabrication of water-dispersed spherical TMDC (MoS2 and WS2) nanoparticles (NPs) of variable size (5 to 250 nm). Such NPs demonstrate exciting optical and electronic properties inherited from TMDC crystals, due to preserved crystalline structure, which offers a unique combination of pronounced excitonic response and high refractive index value, making possible a strong concentration of electromagnetic field in the NPs. Furthermore, such NPs offer additional tunability due to hybridization between the Mie and excitonic resonances. Such properties bring to life a number of nontrivial effects, including enhanced photoabsorption and photothermal conversion. As an illustration, we demonstrate that the NPs exhibit a very strong photothermal response, much exceeding that of conventional dielectric nanoresonators based on Si. Being in a mobile colloidal state and exhibiting superior optical properties compared to other dielectric resonant structures, the synthesized TMDC NPs offer opportunities for the development of next-generation nanophotonic and nanotheranostic platforms, including photothermal therapy and multimodal bioimaging.

Nanoparticle/Core-Shell Composite Structures with Superior Optical and Electrochemical Properties in a Dye-Sensitized Solar Cell.

The dynamics of competition between kinetic electron generation and recombination have restricted the development of a higher-performance dye-sensitized solar cells (DSSC). The key to minimizing the competition is optimizing the nanostructures and thickness of the photoelectrode film. It has been reported that the optimum thickness of photoelectrode film to achieve high-performance efficiency is about 12–14 µm. In this study, a photoelectrode film, which is approximately 4 µm thinner compared with those previously reported and has improved performance efficiency, was successfully developed by using composite nanoparticles and core-shell structures. The fabricated DSSC shows an enhanced light scattering, improved dye absorption capability, and reduced electron recombination rate despite the thinner photoelectrode film. The synthesized elongated nanoparticle structure provides a larger surface area for anchoring more dye molecules. In addition, the micron-sized core-shell structures with different refractive indexes of the inner and outer material resulted in multiple refractions and closed-loop light confinement. The successful development of a high-performance thin photoelectrode film will lead to material and cost savings.

Laser-Enabled Surface Treatment of Disposable Endoscope Lens with Superior Antifouling and Optical Properties.

Endoscopes are ubiquitous in minimally invasive or keyhole surgeries globally. However, frequent removal of endoscopes from the patient’s body due to the lens contaminations results in undesirable consequences. Therefore, a cost-effective process chain to fabricate thermoplastic-based endoscope lenses with superior antifouling and optical properties is proposed in this research. Such multifunctional surface response was achieved by lubricant impregnation of nanostructures. Two types of topographies were produced by femtosecond laser processing of metallic molds, especially to produce single-tier laser-induced periodic surface structures (LIPSS) and two-tier multiscale structures (MS). Then, these two LIPSS and MS masters were used to replicate them onto two thermoplastic substrates, namely polycarbonate and cyclic olefin copolymer, by using hot embossing. Finally, the LIPSS and MS surfaces of the replicas were infiltrated by silicone oils to prepare lubricant-impregnated surfaces (LIS). Droplet sliding tests revealed that the durability of the as-prepared LIS improved with the increase of the lubricant viscosity. Moreover, the single-tier LIPSS replicas exhibited longer-lasting lubricant conservation properties than the MS ones. Also, LIPSS-LIS replicas demonstrated an excellent optical transparency, better than the MS-LIS ones, and almost match the performance of the reference polished ones. Furthermore, the LIPSS-LIS treatment led to superior antifouling characteristics, i.e., regarding fogging, blood adhesion, protein adsorption, and microalgae attachment, and thus demonstrated its high suitability for treating endoscopic lenses. Finally, a proof-of-concept LIPSS-LIS treatment of endoscope lenses was conducted that confirmed their superior multifunctional response.

Pr6O11: Temperature-Dependent Oxygen Vacancy Regulation and Catalytic Performance for Lithium-Oxygen Batteries.

Many challenges still exist in lithium-oxygen batteries (LOBs), particularly exploring an efficient catalyst to optimize the reaction pathway and regulate the Li2O2 nucleation. Pr6O11 has a unique 4f electronic structure and the highest oxygen ion mobility among rare earth oxides, exhibiting superior electronic, optical, and chemical properties. These unique properties might endow it with advanced catalytic activities for LOBs. This work reports two crystal forms of Pr6O11 as novel catalysts and regulates the oxygen vacancy (Vo) concentrations by feasible calcination. Thermogravimetric analysis, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) confirm the conversion from commercial Pr6O11 to cubic fluorite Pr6O11 and Vo-rich Pr6O11. Photographs, high-resolution transmission electron microscopy, selected area electron diffraction, XPS, and electron paramagnetic resonance robustly demonstrate the temperature-dependent evolution of Vo. Ex situ XPS, scanning electron microscopy, and electrochemical techniques are used to study the catalytic mechanism and electrochemical reversibility. It is found that an appropriate Vo concentration can boost O2 adsorption/desorption, accelerate electron transport, and reduce the reaction energy barrier. Vo-rich Pr6O11 optimizes the reaction pathway by offering an intermediate Li2-xO2 (with metalloid conductivity) and adjusting Li2O2 into vertically staggered nanoflakes, effectively avoiding the suffocation of the catalytic surface and presenting excellent capacity, cycling stability, and rate performance.

High responsivity self-powered flexible broadband photodetector based on hybrid Selenium-PEDOT:PSS junction

Hybrid organic-inorganic composites offer solution processability and ease to construct opto-electronic devices with diverse functionalities, which are desirable for applications like flexible and printed electronics. Trigonal Selenium (t-Se) has been recently investigated for photodetector application, owing to its inherent superior optical properties such as high absorption coefficient and photoconductivity. However, most of the reported Selenium photodetectors use vapor transport based device fabrication techniques which require controlled environments and face scalability issues. In this work, high-performance photodetector based on Selenium-PEDOT:PSS hybrid junction is demonstrated using a facile sonication assisted mechanical mixing and drop-casting technique. XRD and Raman analysis reveals the existence of Selenium in trigonal crystal structure and FE-SEM images show clustered nanoparticles. Selenium is mixed with PEDOT:PSS to form bulk heterojunction, which enhances the electron-hole pair separation efficiency and results in improved device responsivity. Also, due to the favorable band offset between Selenium and PEDOT:PSS which results in built-in field, the photodetector operates in self-biased mode. The device exhibits broad spectral response in UV–Vis–NIR range with responsivities of 0.56 A/W, 66 mA/W and 1.363 A/W at 315 nm, 620 nm and 820 nm, respectively. Response times of 7.7 s, 9.4 s and 6.4 s and external quantum efficiencies (EQE) of 192.58%, 13.25% and 206.55% are obtained for UV, Vis and NIR spectra respectively. Further to validate the robustness, the device is subjected to multiple bending cycles (∼2500) and minimal degradation in performance is observed. Given the simple device architecture and facile device fabrication scheme, this work would enable promising approach for high performance flexible photodetectors. • Selenium, possesses high absorption co-efficient and high photoconductivity with optical bandgap of 1.2–1.5 eV. • However, t-Se has been less explored for photodetector applications. • This work reports a solution-processed hybrid-heterojunction based on Se-PEDOT:PSS for photodetection. • The detector exhibits spectral response from UV–Vis to NIR and significant performance at zero bias condition.

Didodecylamine for the synthesis of highly ultrapure green-emitting hybrid perovskite FAPbBr3 nanocrystals

Recently, organometal halide perovskite nanocrystals (NCs) have attracted extensive attention as promising semiconductor materials in photoelectric devices owing to their superior optical properties. Compared with the most reported MAPbBr3 NCs, FAPbBr3 NCs with greener photoluminescence (PL) are popularly expected to be more advantageous photoelectric materials. However, the most commoly used long-chain ligand of oleylamine (OAm) in colloidal FAPbBr3 NCs synthesis impedes charge transport in electroluminescence devices, in addition to increasing the photoluminescence of full width at half maximum (FWHM). Therefore, we proposed a simple method using a shorter amine ligand (didodecylamine) to synthesize FAPbBr3 NCs, which can still obtain a high photoluminescence quantum yield (PLQY) of 98.1% and ultrapure green-emitting at 530 nm with an ultranarrow FWHM of 18.7 nm and good monodispersity. Accordingly, we foresee that such high-efficiency and ultrapure green FAPbBr3 NCs are likely to be applied in the field of optoelectronics.

Frontispiece: Emerging Trends in Fluorescence Bioimaging of Divalent Metal Cations Using Small‐Molecule Indicators

Three new trends in fluorescence bioimaging of divalent metal cations using small-molecule indicators have been highlighted in this concept article by Liu, Zhang and Chen on page 17ff: Red-shifted indicators dwelling in the under-used far-red and NIR channels for multiplexed imaging; hybrid indicators combining the superior optical properties of synthetic dyes and the targetability of proteins; and biocompatible indicators under strong illumination lights in long term recording. These trends fall in line with the new initiative of “4D cellular physiology” which marked a grand vision of biological research in the era of big data.

Emerging exotic properties of two-dimensional ternary tetrahexagonal BCN: Tunable anisotropic transport properties with huge excitonic effects for nanoelectronics and optoelectronics

A two-dimensional ternary tetrahexagonal BCN monolayer (th-BCN) is designed by applying Stone-Wales transformation to its pentagonal counterpart (p-BCN). Using first-principles calculations, we examine the dynamical, mechanical, thermal, and environment stability of th-BCN. The monolayer exhibits superior anisotropic electronic and optical properties compared to its counterparts (the domains of C and BN in the tetrahexagonal network and p-BCN). Direct band gap of 3.05 eV and excellent band edge alignment with the oxidation and reduction reactions of water heralds the use of th-BCN in photocatalytic water splitting. The band gap energy and band edge positions can be further adjusted by strain. The anisotropic high carrier mobility of th-BCN improves fast carrier separation and low recombination rate. The electronic transport direction can be easily controlled by strain engineering. For instance, one can rotate the preferred transport direction of hole by 90° with a very small uniaxial strain. Many-body effects beyond DFT reveal that the monolayer has strong light-harvesting capability (105cm−1) in the visible-ultraviolet region and exhibits strong excitonic effects with large excitonic binding energy of 0.98 eV. All these appealing properties make th-BCN a promising and tunable anisotropic 2D material for nanoelectronic and optoelectronic applications.

Highly efficient UV–visible absorption of TiO2/Y2O3 nanocomposite prepared by nanosecond pulsed laser ablation technique

Nanostructured TiO 2 -based composites are promising materials because of their superior optical, structural, and electronic properties relative to pristine nanostructured TiO 2 . The enhanced properties of TiO 2 -based composites have been used in several important applications such as gas sensors, solar cells, and photocatalytic applications. In the past, numerous materials have been coupled with TiO 2 to enhance their optical properties. In this work, full-spectrum (UV and Visible) responsive TiO 2 /Y 2 O 3 nanocomposite has been synthesized via pulsed laser ablation in liquid (PLA) to study the impact of Y 2 O 3 on the structural, morphology, and optical property of the TiO 2 . The nanostructured composites prepared were characterized by XRD, Raman spectroscopy, Field-Emission Scanning Electron Microscope (FESEM) attached with Energy-Dispersive X-ray spectroscopy (EDX), Photoluminescence, XPS, and UV–Vis absorbance spectra. The result demonstrates that the coupling Y 2 O 3 with TiO 2 not only changes the structural, optical, and morphology of the TiO 2 but also significantly amplified the light absorption characteristics of the TiO 2 within the UV and visible region. The synthesized TiO 2 /Y 2 O 3 nanocomposite could potentially be useful for visible-light responsive applications.

Antiestrogenic property of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF) and its effects on female development in CD-1 mice

Identifying chemicals with endocrine disrupting properties linked to disease outcomes is a key concern, as stated in the WHO-UNEP 2012 report on endocrine-disrupting chemicals. The chemical 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF) is widely and increasingly applied in synthesizing fluorene-based cardo polymers with superior optical, thermal and mechanical properties for various uses. However, little toxicological information is available regarding its safety. Here, we studied the endocrine disrupting property of BPEF by multiple toxicological tools and investigated its effects on female development in adolescent mice. Using the yeast two-hybrid bioassay, BPEF showed strong antiestrogenicity which was similar to that of tamoxifen, an effective antiestrogenic drug. In adolescent CD-1 mice, BPEF significantly decreased the uterine weight at relatively low doses and induced marked endometrial atrophy. Immunohistochemical staining and transcriptome analyses of the mice uteri revealed that BPEF could repressed the expressions of estrogen-responsive genes. Molecular simulation indicated that BPEF could be docked into the antagonist pocket of human estrogen receptor α, and the formation of hydrogen bonds and hydrophobic interactions between BPEF and the active site of receptor maintained their strong binding. All of the data demonstrated that BPEF possessed strong antiestrogenic property and might disrupt female development, suggesting it should be avoided in making products that might directly expose to people, particularly immature women.

Highly Efficient Deep-Blue Phosphorescent OLEDs Based on a Trimethylsilyl-Substituted Tetradentate Pt(II) Complex.

Compared to Ir(III) complexes with octahedral geometries, Pt(II) complexes with square planar geometries show superior optical properties because their flat shapes lead to an orientation that enhances the outcoupling of organic light-emitting diodes (OLEDs). However, the flat shapes of Pt(II) complexes typically induce a bathochromic shift, limiting their application in high-performance deep-blue phosphorescent OLEDs with high color purity. In this study, bulky trimethylsilyl (TMS)-substituted blue phosphorescent Pt(II) complex (PtON7-TMS) is successfully synthesized to improve color purity. The TMS substituent containing Si atom effectively suppresses intermolecular interaction and aggregation even when the complex concentration in the film state is higher than 30 wt %. As a result, the PtON7-TMS-based OLEDs exhibit a maximum external quantum efficiency of 21.4%, along with a pure-blue color of CIE (0.14, 0.09) at 20 wt % doping concentration and a full-width at half maximum of 30 nm. The pure blue color is maintained at a higher doping concentration (>30 wt %).

In Situ Preparation of CsPbBr3 @CsPb2 Br5 Composite Assisted with Water as a Highly Efficient and Stable Catalyst for Photothermal CO2 Hydrogenation.

Lead halide perovskite has triggered a lot of research due to its superior optical properties. However, halide perovskite materials have poor environmental stabilities and are easily affected by external factors such as water and heat, resulting in structural decomposition and performance failure. Contrary to this commonplace concept, it is found that CsPbBr3 (CPB) can convert to CsPb2 Br5 (CP2B5) partially when meeting a small amount of water, and the CsPbBr3 @CsPb2 Br5 (CPB@CP2B5) composite is synthesized by an in situ method accordingly. The CPB@CP2B5 composite shows an enhanced catalytic performance compared with pure CPB, as well as a dramatically synergistic effect of photo and thermal for catalytic CO2 hydrogenation. The CO production rate of CPB@CP2B5 is determined as 69 μmol g-1 h-1 under light irradiation at 200 °C, which is 156.8 and 43.4 times higher than that under pure photo (0.44 μmol g-1 h -1 ) and pure thermal (1.59 μmol g-1 h -1 ) condition, respectively. Meanwhile, the CPB@CP2B5 sample is also stable, which shows no significant decline in the catalytic activity during 8 cycles of repeated experiments. The probable mechanism is explored by utilizing a series of in situ characterizations.

Dynamic response of YAG polycrystalline and single‐crystal transparent ceramics: Experiments and mesoscopic simulations

AbstractDue to superior mechanical and optical properties, yttrium–aluminum–garnet (YAG) is emerging as a potential transparent armor material. Its dynamic behavior, however, remains largely unexplored. In this work, both impact experiments and mesoscopic simulations have been performed to better understand the dynamic response of YAG polycrystalline and single‐crystal transparent ceramics. Experimental results demonstrate that the two samples have remarkably different dynamic behaviors with the increasing shock pressure, in which the Hugoniot elastic limit basically keeps unchanged (∼14 GPa) in YAG polycrystalline ceramic, whereas it varies from 11 to 31 GPa in YAG single crystals. Moreover, elastic precursor decay is visible only in single‐crystal samples. Mesoscopic simulations with a lattice‐spring model reveal that the difference arises from the distinct fracture mode in the two samples. Less damage and coarser fragmentations in YAG single crystal also suggest a probability of better ballistic resistance as transparent armor materials.

Light enhanced the antimicrobial, anticancer, and catalytic activities of selenium nanoparticles fabricated by endophytic fungal strain, Penicillium crustosum EP-1

Selenium nanoparticles (Se-NPs) has recently received great attention over owing to their superior optical properties and wide biological and biomedical applications. Herein, crystallographic and dispersed spherical Se-NPs were green synthesized using endophytic fungal strain, Penicillium crustosum EP-1. The antimicrobial, anticancer, and catalytic activities of biosynthesized Se-NPs were investigated under dark and light (using Halogen tungsten lamp, 100 Watt, λ > 420 nm, and light intensity of 2.87 W m−2) conditions. The effect of Se-NPs was dose dependent and higher activities against Gram-positive and Gram-negative bacteria as well different Candida spp. were attained in the presence of light than obtained under dark conditions. Moreover, the viabilities of two cancer cells (T47D and HepG2) were highly decreased from 95.8 ± 2.9% and 93.4 ± 3.2% in dark than those of 84.8 ± 2.9% and 46.4 ± 3.3% under light-irradiation conditions, respectively. Significant decreases in IC50 values of Se-NPs against T47D and HepG2 were obtained at 109.1 ± 3.8 and 70.4 ± 2.5 µg mL−1, respectively in dark conditions than 19.7 ± 7.2 and 4.8 ± 4.2 µg mL−1, respectively after exposure to light-irradiation. The photoluminescence activity of Se-NPs revealed methylene blue degradation efficiency of 89.1 ± 2.1% after 210 min under UV-irradiation compared to 59.7 ± 0.2% and 68.1 ± 1.03% in dark and light conditions, respectively. Moreover, superior stability and efficient MB degradation efficiency were successfully achieved for at least five cycles.

Pressure and Thickness Dependence of Physical Properties of ZnO:Ga Thin Films by Radio Frequency Magnetron Sputtering

Indium-free transparent conducting oxide films have attracted extensive attention in the field of optoelectronics. Ga-doped ZnO (GZO) thin films are deposited by radio frequency magnetron sputtering on glass substrates at a temperature of 200 °C with ZnO:Ga2O3 (3 wt%). The structural, electrical, and optical properties of the GZO thin films were investigated in terms of deposition pressure and film thickness variations. X-ray diffraction analysis showed that all the prepared GZO films exhibited hexagonal wurtzite crystal structure with a (002) preferential orientation along the c-axis, regardless of pressure and thickness. The average visible transmittance (including the glass substrate) in a wavelength range of 400–700 nm decreased with increasing thickness but varied less with pressure. The highest average visible transmittance reached 88.4% at the thickness of 150 nm and the pressure of 5 mTorr. The optical band gap of the GZO films calculated using Tauc’s method was in the range of about 3.6–3.9 eV. The resistivity of GZO thin films decreased with decreasing deposition pressure and increasing film thickness, and the minimum resistivity obtained at 5 mTorr and 1000 nm was 3.36 × 10-4 Ω-cm. The maximum figure of merit (FOM) of 3.09 × 10-2 Ω-1 was achieved at 5 mTorr and 1000 nm. The superior optical and electrical properties and high FOM show that the prepared GZO thin films are suitable for transparent conducting films and optoelectronic devices.

Temperature-dependent thermoelastic properties of GaSb and InSb semiconductors: Identification through ab initio DFT simulations

III–V semiconductors are extensively used in infrared sensor applications due to their superior structural and optical properties. Due to the extremes in the manufacturing and operating temperatures of the sensors, the knowledge of temperature-dependent elastic constants of these materials is of great importance. However, reliable measurements across a large range of temperatures prove difficult due to limitations of experimental setups. Density functional theory calculations present an affordable alternative. In this work, temperature-dependent elastic properties of InSb and GaSb are investigated using density functional theory within the quasiharmonic approximation. Calculated properties relevant for operation in a wide temperature range are presented including second order elastic constants, Young’s modulus (E), shear modulus (μ), Poisson’s ratio ν and the coefficient of thermal expansion (α). Our results are compared to available experimental values and good agreement is observed.

Effective Passivation of InGaAs Nanowires for Telecommunication Wavelength Optoelectronics

AbstractCatalyst‐free InGaAs nanowires are promising building blocks for optoelectronic devices operating at telecommunication wavelengths. Despite progress, the applications of InGaAs nanowires remain limited due to their high density of surface states that degrade their optical properties. Here, InGaAs nanowires with superior optical properties are achieved by effectively suppressing their surface states with an InP passivation shell. Optimal InP shell growth conditions and thickness to maximize the minority carrier lifetime are identified. The photoluminescence intensity of these passivated InGaAs nanowires is up to three orders of magnitude higher than that of their bare counterparts. Moreover, a long minority carrier lifetime of up to ≈13 ns is measured with these passivated nanowires at room temperature. Optimal passivation of InGaAs nanowires with an emission wavelength of 1530 nm results in an ultra‐low surface recombination velocity of ≈280 cm s−1. In addition to the shell, the crystal structure of these nanowires plays an important role in the luminescence intensity. Combined cathodoluminescence mapping and high‐resolution transmission electron microscopy along the nanowires reveal significantly lower emission intensities in wurtzite predominant sections of the nanowires than zinc blende predominant ones.These insights on the optimal passivation of InGaAs provide directions for engineering high‐performance nanoscale‐devices in the telecommunication wavelength.