Candidozyma auris is an emerging opportunistic fungal pathogen that can cause serious catheter-related blood stream infections associated with high morbidity and mortality. The traditional antifungal treatment with polyenes, azoles or echinocandins is becoming less effective due to both intrinsic and developed resistance, complicating treatment. This study demonstrates the potent fungicidal activity of carboxyl-functionalized graphene quantum dots (cGQDs) against a panel of C. auris strains, spanning clades I to V, and a Candida albicans reference strain. Photoactivation of cGQDs in suspension with 435 nm blue light killed 99.9% of the fungi within 30 min even though the majority of test strains were resistant to at least one conventional antifungal. Moreover, cGQDs coated on flexible polydimethylsiloxane surfaces and commercial catheters via electrostatic layer-by-layer deposition with alternating positively charged polydiallyldimethylammonium polymer showed strong fungicidal activity against C. auris and C. albicans. These findings show that the cGQDs, both in suspension and in a thin film coating, have potential for future clinical development. In particular, their application to catheters may help prevent Candidozyma and Candida catheter-related infections.

InP quantum dots (QDs) have been a major building block of modern display technology due to their high photoluminescence quantum yield (PLQY) in the visible spectrum, superior stability, and eco-friendly composition. However, their applications at short-wave infrared (SWIR) have been hindered by their low efficiency. Here, we report the synthesis of efficient and SWIR-emitting InP QDs by precisely controlling the InP core nucleation using a low-cost ammonia phosphorus precursor, while avoiding size-limiting ZnCl2 for effective copper doping. Subsequent epitaxial growth of a lattice-matched ZnSe/ZnS multishell enhanced the QD sphericity and surface smoothness and yielded a record PLQY of 66% with an emission peak at 960 nm. When QDs were integrated as the high-refractive-index luminescent core of a liquid waveguide-based luminescent solar concentrator (LSC), the device achieved an optical efficiency of 7.36%. This performance arises from their high PLQY, spectral alignment with the responsivity peak of silicon solar cells, and the optimized core/cladding waveguide structure. These results highlight the potential of InP QDs as a promising nanomaterial for SWIR emission and applications.

Nanowires have served as a transformative platform for advanced neural and tissue interfaces. While their photovoltaic properties hold exceptional promise for neural modulation, existing photostimulation approaches predominantly rely on visible light-activated photoelectrochemical mechanisms. Here, we present a solution-processed photovoltaic nanoassembly comprising a ZnO nanowire array sensitized with AgBiS2 nanocrystals that enables efficient near-infrared (NIR) neural stimulation through capacitive photocurrents. By optimizing nanowire morphology and nanocrystal interdigitation, the platform achieves high charge injection densities (tens of microcoulombs per square centimeter) at low NIR intensities (<1 milliwatt per square millimeter). The nanoassembly was subretinally placed in an ex vivo blind rat retina, where it elicited repeatable and robust responses in retinal ganglion cells under NIR pulses. Notably, these responses were achieved at light intensities substantially below established ocular safety limits. The nexus of neuronal systems and nanoassemblies offers potential for enabling unconventional visual prosthetics and advanced neuromodulation therapies.

The retinohypothalamic tract (RHT) is the primary pathway for circadian photoentrainment. Rodent models exhibit a significant translational gap for human physiology due to their nocturnal nature. To overcome this, we developed a functional human RHT assembloid by fusing human pluripotent stem cell (hPSC) derived retinal and hypothalamus organoids. Characterization revealed mature retinal brush borders and the preservation of melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) integrated via excitatory glutamatergic synapses. Multielectrode array (MEA) analysis confirmed synchronized network activity across the interface. The development of the human RHT assembloid represents a significant leap forward in chronobiology. The gold standard for circadian models self-sustained gene expression oscillations was demonstrated using a PER2::Luciferase reporter, showing robust 20-30 hour rhythms. This validates the hypothalamic component as a functional "clock in a dish". This platform provides a readout to screen drugs or test light-pulse effects on circadian phase, directly modeling jet lag or phase-shifting. Overall, this model offers a high-fidelity system for investigating human-specific chronobiological mechanisms in vitro. ### Competing Interest Statement The authors have declared no competing interest. TUBİTAK, 124Z226

2D colloidal nanoplatelets (NPLs) are highly attractive for light-emitting devices (LEDs) due to their thickness-dependent electronic structure and distinct excitonic properties. However, most heterostructured core/shell NPLs predominantly emit in the red spectral region and extending their emission toward shorter wavelengths while preserving optical properties remains a major challenge. Here, we demonstrate a copper-catalyzed cation exchange strategy in CdSe/ZnSe core/shell NPLs that enables continuous spectral tuning. By introducing trace amounts of copper to promote cation diffusion, the emission wavelength can be tuned from 620 to 484 nm, while achieving emission linewidths as narrow as ∼12 nm, among the lowest reported for CdZnSe-based NPLs. The copper concentration serves as an additional key parameter to control the extent of the cation exchange process and the resulting optical properties. Subsequent ZnS shell deposition significantly enhances the photoluminescence quantum yield, reaching near-unity values for red-emitting NPLs and increasing to ∼70% and ∼20% for green- and blue-emitting NPLs, respectively. Using these spectrally tunable and narrow-emitting NPLs, we further demonstrate color-conversion white LEDs with an external quantum efficiency of 30%. These results establish copper-catalyzed cation exchange as a powerful strategy for engineering spectrally tunable NPLs with narrow emission linewidth, providing a viable pathway toward next-generation display technologies.

Aims/Purpose: Nanomaterial based bioelectronics have been effectively developed as optoelectronic bio‐interfaces for neural stimulation and can be fabricated from diverse substances to adapt to cellular environments. In this study, we employed silver bismuth sulfide (AgBiS2) quantum dot (QD)‐based neural interfaces stimulated by near‐infrared light.Methods: Primary neuron isolation and culture on AgBiS2 QD based photovoltaic device and indium tin oxide (ITO) control device was performed. Cell viability was assessed by CTG, MTT, Live/Dead assay and LDH leakage assays. Cellular stress with light stimulation was assessed by measuring intracellular reactive oxygen species. Cell specific biomarkers, NeuN, beta‐III Tubulin and F‐actin, were examined by immunofluorescence staining to demonstrate short‐ and long‐term morphological changes and neural network improvements. Number of neuron count and neurite length measurement were analyzed to compare groups. Under light stimulation (λ = 780 nm), neural dynamics and electrophysiological activity were examined through intracellular calcium flow and patch clamp.Results: Throughout the 14‐day culture period, neurons remained healthy and viable, preserving their characteristics and forming extensive networks with neurite outgrowth on both the device and ITO. Light stimulation was found to have no adverse effects on viability or intracellular stress levels. The device demonstrated successful photostimulation of neurons with calcium release and generating action potential under 780 nm light illumination which is validating its potential to be used as optoelectronic bio‐interfaces for neural applications.Conclusions: Our study holds high potential for the development of QD‐based retinal prosthesis, enabling near infrared light‐controlled activation in vision related diseases.Funding Information: This study was funded by the European Union (ERC, MESHOPTO, 101045289).References Balamur R, Oh JT, Karatum O, Wang Y, Onal A, Kaleli HN, Pehlivan C, Şahin A, Hasanreisoglu M, Konstantatos G, Nizamoglu S. Capacitive and Efficient Near‐Infrared Stimulation of Neurons via an Ultrathin AgBiS2 Nanocrystal Layer. ACS Applied Materials & Interfaces. 2024 May 29

The intrinsic instability of CsPbI3 quantum dots (QDs) presents a major challenge for their practical deployment in optoelectronic devices. Here, we demonstrate the combined effects of Ag+ doping and halide (Cl-/I-) passivation to enhance the structural and optical stability of CsPbI3 QDs. Partial substitution of Pb2+ by Ag+ leads to lattice contraction and defect suppression, while Cl- acts as a surface-localized passivating agent. Structural analyses (X-ray diffraction, high-resolution transmission electron microscopy, and high-resolution scanning transmission electron microscopy) confirm successful Ag+ incorporation without secondary phase formation, and X-ray photoelectron spectroscopy depth profiling reveals surface enrichment of Cl-. Mixed doping with AgCl and AgI precursors effectively stabilizes the cubic perovskite phase, increasing the photoluminescence quantum yield (PLQY) from similar to 85 to 96.6% and reducing nonradiative recombination, as supported by time-resolved photoluminescence measurements. The optimized CsPb1-x Ag x I3 (x = 0.025 AgCl + 0.025 AgI) exhibits outstanding photostability, retaining similar to 41% of its initial PLQY after 70 days of continuous ultraviolet exposure. When integrated into red-emitting light-emitting diode devices, these QDs deliver external quantum efficiencies up to 36.8%, with stable and saturated emission. These results establish Ag+/halide codoping as a powerful strategy to advance CsPbI3 QDs toward robust and high-performance optoelectronic applications.

We developed and characterized near-infrared (NIR)-sensitive photovoltaic cells with tandem photodiodes employing quantum dots (QDs). The tandem structure shows good biocompatibility, enables higher electrochemical photocurrents and allows for enhanced neuron stimulation at infrared.

Objective: A promising avenue for vision restoration against retinal degeneration is the use of semiconductor-based photovoltaic biointerfaces to substitute natural photoreceptors. Instead of silicon, perovskite has emerged as an exciting material for solar energy harvesting, and its nanocrystalline forms generally offer better stability than their bulk counterparts in addition to the distinct synthesis and fabrication steps. Methods: Herein, we synthesize tetramethylammonium lead iodide (TMAPbI3) perovskite quantum dots (QDs) as a novel photoactive material for photovoltaic biointerfaces. While the TMAPbI3 quantum dots and electrolyte interface induces Faradaic photocurrent under light illumination, the heterojunction with P3HT converts the charge-transfer process to a safe capacitive photocurrent with an improved ionic responsivity of 17.4 mA/W. Significance: The integration of the 18-nm quantum dot thickness shows good biocompatibility with primary cultures of hippocampal neurons and the photoresponse of the biointerface triggered photostimulation of the neurons. The rise of perovskite materials can stimulate novel forms of photovoltaic retina implants.

Optoelectronic biointerfaces have emerged as a promising platform for controlling the nervous system at the cellular, tissue, and organ levels with potential clinical applications via transduction of light energy to ionic currents. To improve charge injection, supercapacitor materials like IrO x , TiN, and PEDOT have been incorporated as an additional layer on the photodiodes at electrode–electrolyte interfaces. Here, a bioelectronic design is demonstrated where AgBiS 2 quantum dots (QDs) serve as the photoabsorption material, hole transport medium, and pseudocapacitive electrode–electrolyte interface. The power‐law behavior of the anodic and cathodic peaks suggests that diffusion‐controlled and capacitive processes contribute to the charge storage mechanism. Furthermore, 3D Bode capacitance maps and phase angle responses indicate a high capacitance of 3.3 mF cm⁻ 2 at the half‐wave potential (0.044 V vs Ag/AgCl) in artificial cerebrospinal fluid (aCSF). For efficient transduction of light to electrical stimulation, AgBiS 2 QDs are embedded onto ZnO nanowires (NWs) in a photovoltaic device architecture, which produces twice the photocurrent (1.9 ± 0.3 mA cm⁻ 2 ) and nearly three times the charge injection (29 ± 2.3 µC cm⁻ 2 ) compared to the planar devices without NWs. Moreover, photostimulation of hippocampal neurons is demonstrated on the device without inducing significant oxidative stress. This study demonstrates an unconventional and efficient bioelectronic device via pseudocapacitive optoelectronic nanocrystals.

Cu-doped InP/ZnSe/ZnS quantum dots (QDs) emitting short-wave infrared at 960 nm were synthesized with a high quantum efficiency of 66%. Efficient luminescent solar concentrators with an optical efficiency of 7.36% were fabricated via liquid-state QD-injection.

Bacterial infections are a major healthcare concern. Clinical application of photo-activated quantum dots to efficiently treat bacterial infections has been hindered by inadequate production of reactive oxygen species. In this study, photoactive antimicrobial carboxyl-functionalized graphene quantum dots (cGQDs) are synthesized with an exceptionally high singlet oxygen (1O2) quantum yield of 0.88. Compared to non-functionalized GQDs, cGQDs exhibit over a 20-fold enhancement in the 1O2 quantum yield. According to the density functional theory simulations, the dramatic increase of 1O2 quantum yield is due to significantly enhanced spin-orbit coupling between singlet and triplet excited states of GQDs with addition of & horbar;COOH groups. Under low-intensity blue light (5 mW cm- 2), Staphylococcus aureus is completely eliminated with just 0.8 mu g mL-1 of cGQDs, and a minimum bactericidal concentration (MBC) of 0.4 mu g mL-1 is determined, representing the lowest MBC reported against S. aureus using light-activated quantum dots. Layer-by-layer assembly of cGQD films also results in over a 99.9% reduction against multi-drug resistant Staphylococcus aureus and Escherichia coli under illumination. cGQDs, both in suspension and as a nano-assembled film, exhibit good cell viability in mammalian cells under both dark and light conditions. These results highlight the strong potential of cGQDs as an effective nanomaterial for antibacterial applications.

Cardiovascular diseases are a leading global cause of mortality and bradycardia, a slow heart rate due to impaired cardiac conduction that poses significant health risks. While conventional pacemakers restore heart rate, their dependence on leads and battery lifetime remain major drawbacks. Cardiac photostimulation emerges as a transformative alternative, enabling wireless, battery-free pacing. Here, a hydrogel-integrated optoelectronic biointerface based on AgBiS2 quantum dots (QDs) is presented for near-infrared (NIR) cardiac photostimulation. The incorporation of a thin (approximate to 0.1 mu m), conductive (approximate to 200 mS cm-1), and soft (390 kPa) PEDOT:PSS hydrogel enhanced ionic charge transfer by 52.8-fold (reaching 28 mu C cm-2) under pulsed infrared illumination compared to hydrogel-free controls. The biointerface generated photocurrent loops between the stimulation and return electrodes that are predominantly capacitive and charge-balanced, with minimal faradaic contribution (approximate to 1%) and negligible thermal effects (Delta T approximate to 0.2 K). Cardiac motion analysis using a custom image-processing algorithm confirmed modulation of beating frequency of cardiac tissue explants, ranging from bradycardic (<60 bpm) to physiological (approximate to 120 bpm) rates. This work establishes a compelling strategy for integrating the optoelectronic properties of quantum dots with soft organic materials, paving the way for next-generation, minimally invasive bioelectronic devices.

We introduce the Optical Materials Express feature issue on Novel Optical Materials and Applications (NOMA). This issue comprises a collection of fifteen papers that highlight recent progress in the design, fabrication, characterization, and theoretical analysis of advanced optical materials and photonic structures. This feature issue is built upon the 2024 Novel Optical Materials and Applications (NOMA) Conference, part of the Optica Advanced Photonics Congress that was held in Qu & eacute;bec City, Qu & eacute;bec, Canada in 2024. (c) 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

An optoelectronic biointerface incorporating AgBiS2 nanocrystals and ZnO nanowires was nanoengineered for infrared neural modulation. The biointerface exhibits high photostability and efficient charge injection, enabling ex-vivo retina photostimulation.

AgBiS2 nanocrystals (NCs), composed of nontoxic, earth-abundant materials and exhibiting an exceptionally high absorption coefficient from visible to near-infrared (>105 cm-1), hold promise for photovoltaics but have lack of photoluminescence (PL) due to intrinsic nonradiative recombination and challenging shell growth. In this study, we reported a facile wet-chemical approach for the epitaxial growth of ZnS shell on AgBiS2 NCs, which triggered the observation of PL emission in the near-infrared (764 nm). Since high quality of the core is critical for epitaxial shell growth, we first obtained rock-salt structured AgBiS2 NCs with high crystallinity, nearly spherical shape and monodisperse size distribution (<6%) via a dual-ligand approach reacting Ag-Bi oleate with elemental sulfur in oleylamine. Next, a zincblende ZnS shell with a low-lattice mismatch of 4.9% was grown on as-prepared AgBiS2 NCs via a highly reactive zinc (Zn(acac)2) precursor that led to a higher photoluminescence quantum yield (PLQY) of 15.3%, in comparison with a relatively low reactivity precursor (Zn(ac)2) resulting in reduced PLQY. The emission from AgBiS2 NCs with ultrastrong absorption, facilitated by shell growth, can open up new possibilities in lighting, display, and bioimaging.

The emergence of multidrug-resistant bacteria as a global health threat has necessitated the exploration of alternative treatments to combat bacterial infections. Among these, photocatalytic nanomaterials such as quantum dots (QDs) have shown great promise and type-I QDs have been investigated thus far. In this study, we introduce type-II InP/ZnO core/shell QDs that are ligand-exchanged with a short-chain inorganic sulfide ion (S2-) for antibacterial activity. Interestingly, InP/ZnO QDs simultaneously generate reactive oxygen species (ROS) including hydroxyl (center dot OH) and superoxide (O-2(center dot-) ) radicals, while only O-2(center dot-) radicals can be released by the type-I sulfide-capped InP/ZnS QDs. The optimized nanostructure achieved effective inhibition of Pseudomonas aeruginosa and Escherichia coli bacteria growth to the level of 99.99% and 70.31% under low-intensity green light illumination of 5 mW.cm(-2). Our findings highlight the importance of type-II QDs as a new avenue for developing effective antibacterial agents against drug-resistant pathogens.

In recent years, colloidal quantum dots (QDs) derived from inorganic halide perovskites have shown great promise in optoelectronic applications. Despite their promising optical properties, the full potential of CsPbI3 QDs is significantly undermined by high surface trap densities and poor environmental stability. To address these challenges, this research focuses on an innovative approach involving synergetic Co2+ doping of CsPbI3 QDs and I-/Cl- ion passivation. Co2+ doping is achieved by utilizing various dopant sources such as CoI2, CoCl2 and mixed CoI2/CoCl2 The anions from CoCl(2)and CoI2 occupy iodide vacancies, thereby reducing nonradiative recombination. The optimized composition, CsPb(0.9)5Co(0.05)I(3) QDs with mixed CoI2/CoCl(2)( )doping, exhibits exceptionally low trap density and superior stability. The superior efficacy of mixed doping compared to sole CoCl2 doping suggests the complementary action of I- ions (from CoI2) along with Cl- ions (from CoCl2) in passivating surface defects. Optimized CsPb(0.9)5Co(0.05)I(3) QDs demonstrate a significant boost in photoluminescence (PL) performance and stability, achieving an exceptional 98.86% PL quantum efficiency while maintaining stability for over two months under UV light exposure. Integration of the optimized QDs into LED devices yields an outstanding external quantum efficiency (EQE) of 34.6%, showcasing their promising potential for efficient lighting applications.

Neuromorphic electronics, inspired by the functions of neurons, have the potential to enable biomimetic communication with cells. Such systems require operation in aqueous environments, generation of sufficient levels of ionic currents for neurostimulation, and plasticity. However, their implementation requires a combination of separate devices, such as sensors, organic synaptic transistors, and stimulation electrodes. Here, a compact neuromorphic synapse that combines photodetection, memory, and neurostimulation functionalities all-in-one is presented. The artificial photoreception is facilitated by a photovoltaic device based on cell-interfacing InP/ZnS quantum dots, which induces photo-faradaic charge-transfer mediated plasticity. The device sends excitatory post-synaptic currents exhibiting paired-pulse facilitation and post-tetanic potentiation to the hippocampal neurons via the biohybrid synapse. The electrophysiological recordings indicate modulation of the probability of action potential firing due to biomimetic temporal summation of excitatory post-synaptic currents. These results pave the way for the development of novel bioinspired neuroprosthetics and soft robotics, and highlight the potential of quantum dots for achieving versatile neuromorphic functionality in aqueous environments.