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.

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.

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.

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.

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.

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.

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.

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.

Colloidal nanocrystals (NCs) exhibit significant potential for photovoltaic bioelectronic interfaces because of their solution processability, tunable energy levels, and inorganic nature, lending them chemical stability. Silver bismuth sulfide (AgBiS2) NCs, free from toxic heavy-metal elements (e.g., Cd, Hg, and Pb), particularly offer an exceptional absorption coefficient exceeding 10(5) cm(-1) in the near-infrared (NIR), surpassing many of their inorganic counterparts. Here, we integrated an ultrathin (24 nm) AgBiS2 NC layer into a water-stable photovoltaic bioelectronic device architecture that showed a high capacitive photocurrent of 2.3 mAcm(-2) in artificial cerebrospinal fluid (aCSF) and ionic charges over 10 mu Ccm(-2) at a low NIR intensity of 0.5 mWmm(-2). The device without encapsulation showed a halftime of 12.5 years under passive accelerated aging test and did not show any toxicity on neurons. Furthermore, patch-clamp electrophysiology on primary hippocampal neurons under whole-cell configuration revealed that the device elicited neuron firing at intensity levels more than an order of magnitude below the established ocular safety limits. These findings point to the potential of AgBiS2 NCs for photovoltaic retinal prostheses.

Semiconductor photocatalysis has recently emerged as a promising method for microbial inactivation. So far, quantum dots have generally been investigated as antibacterial suspension. Instead, here we demonstrate a InP/ZnS quantum dot nanoassembly film against both Gram-negative and Gram-positive bacteria. For effective operation in the solid phase, a thin layer of ZnS shell was grown on InP QD and the native long-chain ligand of stearic acid was replaced with sulfide that led to a high quantum yield of superoxide generation as 4.9%. QDs are assembled onto solid surfaces through sequential dip coating of positively charged poly(diallyldimethylammonium chloride) and negatively charged QDs. These QD nanoassemblies demonstrate growth inhibition against Escherichia coli and multidrug-resistant Staphylococcus aureus under illumination. Interestingly, such an approach can be directly applied to irregular surfaces, as well. This study unveils the potential of the nanoengineering of QDs for antibacterial coatings.

Light-based neuromodulation systems offer exceptional spatiotemporal resolution combined with the elimination of physical tether to communicate with neurons. Currently, optical neuromodulation systems ranging from the nano to the centimeter scale enable neural activity control from the single cell to the organ level in retina, heart, spinal cord, and brain, facilitating a wide range of experiments in intact and freely moving animals in different contexts, such as during social interactions and behavioral tasks. Nanotransducers (e.g., metallic nanoparticles, silicon nanowires, and polymeric nanoparticles) and microfabricated photodiodes convert light to electrical, thermal, and mechanical stimuli that can allow remote and non-contact stimulation of neurons. Moreover, integrated devices composed of nano and microscale optoelectronic components comprise fully implantable and wirelessly powered smart optoelectronic systems that exhibit multimodal and closed-loop operation. In this review, we first discuss the material platforms, stimulation mechanisms, and applications of passive systems, i.e., nanotransducers and microphotodiodes. Then, we review the use of organic and inorganic light-emitting diodes for optogenetics and implantable wireless optoelectronic systems that enable closed-loop optogenetic neuromodulation through the use of light-emitting diodes, wireless power transfer circuits, and feedback loops. Exploration of materials and mechanisms together with the presented applications from both research and clinical perspectives in this review provides a comprehensive understanding of the optical neuromodulation field with its advantages and challenges to build superior systems in the future.

AbstractOptoelectronic biointerfaces have gained significant interest for wireless and electrical control of neurons. Three–dimentional (3D) pseudocapacitive nanomaterials with large surface areas and interconnected porous structures have great potential for optoelectronic biointerfaces that can fulfill the requirement of high electrode‐electrolyte capacitance to effectively transduce light into stimulating ionic currents. In this study, the integration of 3D manganese dioxide (MnO2) nanoflowers into flexible optoelectronic biointerfaces for safe and efficient photostimulation of neurons is demonstrated. MnO2 nanoflowers are grown via chemical bath deposition on the return electrode, which has a MnO2 seed layer deposited via cyclic voltammetry. They facilitate a high interfacial capacitance (larger than 10 mF cm−2) and photogenerated charge density (over 20 µC cm−2) under low light intensity (1 mW mm−2). MnO2 nanoflowers induce safe capacitive currents with reversible Faradaic reactions and do not cause any toxicity on hippocampal neurons in vitro, making them a promising material for biointerfacing with electrogenic cells. Patch‐clamp electrophysiology is recorded in the whole‐cell configuration of hippocampal neurons, and the optoelectronic biointerfaces trigger repetitive and rapid firing of action potentials in response to light pulse trains. This study points out the potential of electrochemically‐deposited 3D pseudocapacitive nanomaterials as a robust building block for optoelectronic control of neurons.

Photostimulation of Neurons In article number 2301854, Lokman Kaya, Sedat Nizamoglu, and co-workers integrate MnO2 nanoflowers into a photovoltaic biointerface for photostimulation of neurons. Nanoflowers with large-surface areas and high electro-electrolyte capacitance enable safe and efficient capacitive photocurrents that lead to repetitive and successful stimulation of neurons under light pulses. This study reveals the high potential of 3D capacitive nanomaterials for bioelectronics.

In recent years quantum dots (QDs) emerge as a powerful building block for liquid‐crystal display (LCD) technology, and they are successfully used in the form of color enhancement films. However, their transition toward efficient and wide color gamut LEDs for backlighting remain as an important challenge, which can decrease the required amount of QDs per TV for orders of magnitude. Herein, QD‐based white LEDs are reported that can simultaneously operate with a high external quantum efficiency (EQE) of 39.8% and a wide NTSC color gamut coverage of 133.3%. For red‐emitting spectral range, giant CdSe/CdS core/shell QDs are synthesized via hot injection method, and it is observed that 20 monolayers of CdS shell can lead to a near‐unity photoluminescence quantum yield (PLQY) of 98%. In addition, green‐emitting CdZnSeS/ZnS alloyed core/shell QDs show a PLQY of 97% with a narrow full width at half maximum (FWHM) of 20 nm. To maintain the optical properties of QDs in device architecture, QDs are injected in liquid matrix on blue LED chips and used as the backlighting source for LCD TV that lead to bright and vivid colored images. QD‐based white LEDs with high efficiency and wide color gamut have significant potential for next‐generation display technology.

The synthesis of various transition-metal-doped InP quantum dots (QDs), such as copper, manganese, and silver, for enhanced optoelectronic properties has been reported to date. Herein, we introduce ruthenium (Ru) doping into InP QDs. After Ru doping, InP QDs showed a significant red shift up to 325 meV due to the introduction of mid-gap states. The optimization studies of the ZnS shell formation on Ru-doped InP core QDs led to a high photoluminescence quantum yield (PLQY) of 77.6% in the red spectral region, while without ruthenium doping the PLQY reached a maximum level around 60% via the same synthetic approach. Elemental mapping, mass spectrometry, and lattice change confirmed the incorporation of Ru inside the InP QDs. Moreover, the integration of Ru-doped QDs into LEDs in a liquid matrix led to an external quantum efficiency of 7.9%. This study demonstrates that Ru doping can be an alternative strategy for efficient red emitters.

We developed quantum dot (QD) based color-conversion white LEDs that reach over 150 lumens per electrical Watt. For that we synthesized alloyed ZnCdSe/ZnSe QDs with 94% of quantum efficiency and injected QD-liquids on blue LEDs.