Physical unclonable functions (PUFs) based on nanophotonic materials offer a promising route toward secure and tamper-resistant authentication. Here, we introduce a quantum dots (QDs)-driven optical fingerprinting (identifier) platform that utilizes four distinct photoluminescence (PL) emission peaks generated from two cadmium-free CIS/ZnS QDs formulations deposited side-by-side. Under multiwavelength excitation, each of them exhibits a dual-peak emission response, yielding a combined four-peak, multiexcitation spectral profile. By extracting the wavelength, full width at half-maximum, and intensity from each peak across nine excitation wavelengths, we obtain 108 independent spectral features, which are converted into a 216-bit binary fingerprint. This work incorporates a features fusion strategy that compresses multidimensional spectral descriptors into compact, discriminative digital features, enabling stable, high-entropy encoding from complex PL emission behavior. Comprehensive statistical analysis demonstrates strong uniqueness with a mean inter-Hamming distance of 0.512 ± 0.028, a wide collision margin of 99-123 differing bits, and repeatability with near-zero intra-tag variation. Bit-level randomness metrics confirm near-ideal statistical behavior after binarization. The four-peaks architecture therefore represents a significant advancement over single-peak or dual-peaks luminescent PUFs, enabling dense, high-entropy fingerprints from cadmium-free materials while remaining compatible with typical readout hardware. This work establishes a foundation for next-generation optical authentication technologies using multipeak QDs emitters.

Two-dimensional transition metal dichalcogenides (TMDCs) are highly anisotropic, layered semiconductors, with the general formula ME2 (M = metal, E = sulfur, selenium or tellurium). Much current research in this field focusses on TMDCs for catalysis and energy applications; they are also attracting great interest for next-generation transistor and optoelectronic devices. The latter high-tech applications place stringent requirements on the stoichiometry, crystallinity, morphology and electronic properties of monolayer and few-layer materials. As a solution-based process, wherein the material grows specifically on the electrode surface, electrodeposition offers great promise as a readily scalable, area-selective growth process. This Review explores the state-of-the-art for TMDC electrodeposition, highlighting how the choice of precursor (or precursors), solvent and electrode designs, with novel ‘device-ready’ electrode geometries, influence their morphologies and properties, thus enabling the direct growth of ultrathin, highly anisotropic 2D TMDCs and much scope for future advances. Electrochemical methods to grow 2D metal chalcogenides are reviewed, emphasizing the effects of the precursor (or precursors), solvent and electrode designs. Emerging work using nano-band electrodes to promote in-plane 2D layer growth into ‘device-ready’ electrode structures is highlighted.

Integrating graphene and transition metal dichalcogenides (TMDs) into layered material heterostructures brings together the exciting properties that each constituent 2D material offers. However, scaling the growth of graphene-TMD and related heterostructures remains a major challenge. In this work, we demonstrate the use of electrodeposition with a single source precursor (SSP), WSeCl4, to grow few-layer WSe2 using graphene as an electrode. Through characterization via photoluminescence, X-ray photoelectron, and Raman spectroscopy, we show that the electrodeposited WSe2 is stoichiometric and exhibits semiconducting and light-emitting properties. TEM imaging was also performed to show the ordering of the stacked layers of WSe2 over graphene, demonstrating the polycrystalline structure of WSe2. This work paves the way toward utilizing electrodeposition to stack multiple TMDs, including MoS2, WS2, and WSe2 over graphene for electronic and optoelectronic applications.

Vanadium dioxide (VO2) is a popular phase-transition material with broad applications ranging from thermal management in smart windows to neuromorphic computing. Currently, VO2 thin films are usually fabricated at high temperatures, making them incompatible in forming on top of CMOS and flexible polyimide substrates. This study explores a low-temperature VO2 thin film formation approach that combines atomic layer deposition (ALD) with a post-deposition anneal. With systematic material characterizations, we clearly demonstrate high-quality VO2 film formation on Si substrates at a significantly reduced annealing temperature of 300 degrees C. Further reducing the annealing temperature to 250 C-o is shown to lead to insufficient VO2 crystallization whilst elevating the temperature to 400 C-o results in overoxidation into V2O5. We implement our method on polyimide substrates and demonstrate that the high-quality phase transition is indeed preserved. This work demonstrates the ability of low-temperature formation of VO2 thin films, and it will accelerate the adoption of VO2 in emerging electronic devices as well as photonic applications.

Chalcogenide materials are promising candidates for next generation memories since they can be stacked to integrate both two-terminal non-volatile memory and volatile selector devices for large-scale-integration crossbar arrays. Traditionally, devices based on chalcogenides have been fabricated using vacuum-dependent and high-temperature methods. In this study, the first demonstration of ovonic threshold switching (OTS) and resistive switching (RS) behaviors in zinc telluride (ZnTe) thin films produced via a rapid, cost-effective, and vacuum-free electrodeposition technique is presented. This method also allows for control over ZnTe film composition within the same electrolyte by varying the deposition potentials. These findings reveal that stoichiometric ZnTe thin films exhibit OTS behavior, while Te-rich ZnTe films display RS characteristics. The OTS selectors show robust threshold switching with controllable operating current levels, whereas the RS memory devices demonstrate reliable switching at low voltages, achieving multilevel switching through variations in DC sweeping voltages. A one-selector-one-resistor (1S1R) architecture is successfully implemented by connecting the stoichiometric ZnTe selector in series with the Te-rich ZnTe memory element, thereby validating the potential of OTS as a selector for crossbar applications. This work provides a significant advancement toward constructing stacked structures of memory and selector devices through electrodeposition methods, paving the way for high-density crossbar array applications.

Counterfeiting and unauthorized duplication continue to pose significant threats across industries, ranging from electronics to pharmaceuticals. In response to this challenge, we present a novel optical fingerprinting platform based on cadmium-free CuInS2/ZnS quantum dots (QDs), which exhibit a distinctive dual-peak photoluminescence (PL) signature. Time-resolved PL (TRPL) analysis confirms the distinct recombination origins of the two peaks, supporting the assignment to core- and interfacial/shell-related states. Our approach extracts two intrinsically coupled emissions from a single QD type, where both peaks originate within the same nanostructure, making the fingerprint inherently unclonable. This phenomenon enables the generation of rich tunable spectral profiles across a selected range of excitation wavelengths. Using spectral-to-digital processing, we extracted three features from both emission peaks under 10 excitation wavelengths to generate binary fingerprints. The resulting theoretical encoding capacity is estimated to be 1.2 × 1018 compared to an experimental error probability of ∼3 × 10-17. These findings validate the strength and security of the proposed fingerprinting system, highlighting its practical potential for anticounterfeiting applications.

Few layer transition metal dichalcogenides (TMDCs) are currently a hot topic in electrochemistry with a focus on their applications in electrocatalysis, energy conversion and storage, and sensors because of their high surface areas and unique properties. At the same time there is even greater interest in the field of electronics for the applications of few layer TMDCs in nanoelectronic devices including field effect transistors, memristors, photodetectors, and flexible electronics. Here we highlight the significant opportunities and challenges in the practically unexplored use of electrodeposition and electrochemical processes for the fabrication of TMDC based electronic devices.

Bolometers rely upon the temperature coefficient of resistance (TCR) of their underpinning sensing layer to detect infrared radiation. Vanadium dioxide (VO2) exhibits a very large, but abrupt TCR associated with its monoclinic to rutile phase transition. W-doping of VO2 lowers and broadens its transition temperature, and by combining multiple discrete W:VO2 layers, a sensing layer can be created with an extended temperature operation region. Herein, we report such a multilayer W:VO2 thin film by atomic layer deposition (ALD). The film displays an average TCR of -9.5 (±3.5) %K-1 from 30°C to 60°C. A sensing layer consisting of 10 individual W:VO2 layers is simulated with a multi-objective genetic algorithm (MOGA) for maximum average TCR (μ) and minimum variation (σ) across an extended target temperature range producing an optimized layer structure at max ( |μ|-σ ) with average TCR response of -6.7 (±0.9) %K-1 from 20°C to 70°C. This work highlights the potential for the broader application of uncooled bolometers.

Two-dimensional (2D) transition metal dichalcogenides (TMD) have gathered significant attention in flexible electronics and optoelectronics research due to their unique electronic and optical properties attributed to their size-dependent band gap. Their layered structure befits the fabrication of heterostructures by combining different TMDs, translating directly to the formation of heterojunctions (p-n junction), advantageous for device applications. 1 Recent advances show impressive monolayer interfaces, but many remain as a single device, derived from exfoliation processes on single flakes. Electrodeposition has recently emerged as a potential low cost and readily scalable technique to deposit TMDs, with demonstrated examples of MoS 2 , WS 2 and WSe 2 . 2,3 Additionally, area-selective lateral electrodeposition from the edges of a TiN nanoband electrode structure, has enabled the growth of TMDs over an insulating substrate (SiO 2 ) and made possible to measure their electrical properties directly. This fabricated microelectrode structure shown in Figure 1 below, allows multiple individual electrodes to be made active for the controlled growth of each film. We demonstrate the electrodeposition of a TMD heterostructure in the present work, with MoS 2 -WSe 2 heterojunction as a first example. A heterostructure is created by first electrodepositing MoS 2 from the upper electrodes only, to partially cover a 2 µm gap. In the second step, WSe 2 is electrodeposited from the lower electrodes, until it contacts the upper MoS 2 . This produces an MoS 2 -WSe 2 heterojunction over the SiO 2 channel, while offering a simple workflow with fewer steps towards achieving a functional semiconducting interface. Electrodeposition usually yields TMD materials with amorphous/nanocrystalline structure and therefore a thermal annealing step is required. Furnace annealing is performed for individual TMD materials, however, a single step annealing of MoS 2 -WSe 2 heterostructure brings complications due to the chalcogen diffusion and chances of mixed phase formation. Therefore, Raman laser annealing is used in the present work to crystallise the heterostructure, in a scanning electron microscope, coupled with a correlative Raman spectrometer. This enables the seamless study of film morphology, composition and structure in a single instrument. Laser annealing itself, offers interesting opportunities compared to traditional methods, such as avoiding thermal stress to the entire device (crucial for flexible substrates and reduces leakage faults), annealing speed, real-time quality monitoring and the ability to scribe custom crystalline electrical connections for new novel applications. 4 The Raman laser achieves a spot size of ~432 nm, which together with a laser power of 12 mW is found to be sufficient to anneal the materials within seconds, confirmed by the evolution of the signature vibrational modes of MoS 2 and WSe 2 . For the first time in these materials, Raman thermometry is employed to measure the anti-Stokes and Stokes peak ratios and to calculate the theoretical local temperatures. For the 12 mW power used on MoS 2 and WSe 2 , the temperature calculation equates to 650 °C and 589 °C respectively. This is in agreement with Raman data comparatively obtained by furnace annealing of individual materials. The laterally grown MoS2-WSe2 heterostructure allowed direct measurement of their electrical properties. Pre and post annealing current-voltage (IV) measurements reveal that the addition of a Raman laser annealed line connection, induces an asymmetrical IV response, indicative of a heterojunction. High resolution transmission electron microscopy (TEM) has been used to compare the amorphous and laser annealed heterostructure, revealing the 2D material structure in both the MoS 2 and WSe 2 films at the laser treated areas. The 2D grain orientation predominantly shows alignment along the lateral direction of growth, which demonstrates a promising method towards creating edge-by-edge interface heterostructures for future device applications. The authors kindly acknowledge the support of EPSRC grants EP/V062689/1 and EP/V007629/1. References: (1) Wang, J.; Li, Z.; Chen, H.; Deng, G.; Niu, X. Recent Advances in 2D Lateral Heterostructures ; Springer Singapore, 2019; Vol. 11. https://doi.org/10.1007/s40820-019-0276-y. (2) Abdelazim, N. M.; Noori, Y. J.; Thomas, S.; Greenacre, V. K.; Han, Y.; Smith, D. E.; Piana, G.; Zhelev, N.; Hector, A. L.; Beanland, R.; Reid, G.; Bartlett, P. N.; de Groot, C. H. Lateral Growth of MoS2 2D Material Semiconductors Over an Insulator Via Electrodeposition. Adv Electron Mater 2021 , 7 (9). https://doi.org/10.1002/aelm.202100419. (3) Thomas, S.; Greenacre, V. K.; Zhang, J.; Zhelev, N.; Ramadan, S.; Han, Y.; Beanland, R.; Abdelazim, N. M.; Noori, Y. J.; de Groot, K.; Reid, G.; Bartlett, P. N. Electrodeposition of 2D Layered Tungsten Diselenide Thin Films Using a Single Source Precursor. J Mater Chem C Mater 2024 . https://doi.org/10.1039/d4tc02755h. (4) Becher, M. J. M. J.; Jagosz, J.; Neubieser, R. M.; Wree, J. L.; Devi, A.; Michel, M.; Bock, C.; Gurevich, E. L.; Ostendorf, A. Ultrashort-Pulsed-Laser Annealing of Amorphous Atomic-Layer-Deposited MoS2 Films. Adv Eng Mater 2023 , 25 (21), 1–8. https://doi.org/10.1002/adem.202300677. Figure 1

In this work, we present a method for direct, site-selective growth of tellurium nanowires by electrochemical deposition. The Te nanowires were grown laterally between two specially designed nanoband electrodes across a gap, and over a dielectric material, forming a lateral device structure directly. The resulting wires are crystalline and phase pure, as evidenced by Raman spectroscopy, EDS (energy dispersive X-ray spectroscopy), and ADF-STEM (annular dark field scanning transmission electron microscopy). The precise conditions for lateral growth of the nanowires were investigated and the fabrication of an electronic device from the as-deposited material, without the need for any transfer process or further contact fabrication, is demonstrated.

The development of area-selective, scalable deposition methods for the anisotropic growth of transition metal dichalcogenide (TMDC) thin films with a planar morphology is essential for their practical applications in integrated electronic and optoelectronic devices. In this work, we report on the electrodeposition of layered WSe2 from a single source molecular precursor, containing both W and Se, for the first time. Using WSeCl4 in an acetonitrile (MeCN) electrolyte solution, we have employed cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM) techniques to study the electrochemical behaviour of WSeCl4. A pulsed electrodeposition technique was then used to deposit WSe2 films, which possess a homogeneous composition across the whole electrode area. Characterization using scanning and transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy confirm the electrodeposited thin films to be WSe2. As a proof-of-concept for future growth directly into 3D device architectures, we present the 2D anisotropic growth of WSe2 thin films from the edge of a 100 nm thick TiN nanoband electrode across SiO2 on microfabricated 3D structures, allowing the direct measurement of electrical characteristics. Through this work, we also demonstrate electrodeposition as an area-selective growth technique suitable for obtaining highly anisotropic WSe2 thin films which are very promising for future electronic and optoelectronic applications. We report the electrodeposition of WSe2 thin films using a single source precursor (WSeCl4) and its 2D anisotropic growth from a microfabricated TiN nanoband electrode across an insulator, allowing direct electrical characterization.

Integrating resistive memory or neuromorphic memristors into mainstream silicon technology can be substantially facilitated if the memories are built in the back-end-of-line (BEOL) and stacked directly above the logic circuitries. Here we report a promising memristor employing a plasma-enhanced chemical vapour deposition (PECVD) bilayer of amorphous SiC/Si as device layer and Cu as an active electrode. Its endurance exceeds one billion cycles with an ON/OFF ratio of ca. two orders of magnitude. Resistance drift is observed in the first 200 million cycles, after which the devices settle with a coefficient of variation of ca. 10% for both the low and high resistance states. Ohmic conduction in the low resistance state is attributed to the formation of Cu conductive filaments inside the bilayer structure, where the nanoscale grain boundaries in the Si layer provide the pre-defined pathway for Cu ion migration. Rupture of the conductive filament leads to current conduction dominated by reverse bias Schottky emission. Multistate switching is achieved by precisely controlling the pulse conditions for potential neuromorphic computing applications. The PECVD deposition method employed here has been frequently used to deposit typical BEOL SiOC low-k interlayer dielectrics. This makes it a unique memristor system with great potential for integration.

This paper presents a series of techniques for improving the intrinsic matching of large capacitor arrays used in charge redistribution C-DACs for successive approximation register (SAR) analog to digital converters (ADCs). The analysis takes an in-depth look at the geometry of the capacitors implemented in a 40nm CMOS process, minimising sources of mismatch, analysing in detail the impact of finger spacing, metal width, and finger length. The impact of local array gradient is also considered in both the X and Y dimension, providing a recommendation for preventing parabolic gradient effects. The random and systematic mismatch errors are quantified and decorrelated, with the systematic element showing strong geometry dependency, being the dominant source of error in specific configurations. The approach overcomes the gain errors introduced by the usage of a sub-DAC (typically 1-5% error). The capacitors are implemented in a commercial 40nm process and bonded in a QFN package. The measurement results show 4 to 7 times improvement in the total mismatch error with respect to conventional MOM capacitor arrays. The equivalent SNR improvement within an uncalibrated SAR ADC is 16.7dB, which is sufficient for achieving 16-bit uncalibrated linearity

In response to the growing need for efficient processing of temporal information, neuromorphic computing systems are placing increased emphasis on the switching dynamics of memristors. While the switching dynamics can be regulated by the properties of input signals, the ability of controlling it via electrolyte properties of a memristor is essential to further enrich the switching states and improve data processing capability. This study presents the synthesis of mesoporous silica (mSiO2) films using a sol-gel process, which enables the creation of films with controllable porosities. These films can serve as electrolyte layers in the diffusive memristors and lead to tunable neuromorphic switching dynamics. The mSiO2 memristors demonstrate short-term plasticity, which is essential for temporal signal processing. As porosity increases, discernible changes in operating currents, facilitation ratios, and relaxation times are observed. The underlying mechanism of such systematic control was investigated and attributed to the modulation of hydrogen-bonded networks within the porous structure of the silica layer, which significantly influences both anodic oxidation and ion migration processes during switching events. The result of this work presents mesoporous silica as a unique platform for precise control of neuromorphic switching dynamics in diffusive memristors.

Photovoltaic-Thermoelectric Generator (PV-TEG) system has emerged as a promising approach to significantly enhance the efficiency of conventional PV cells. However, optimizing the performance of these hybrid systems presents a formidable challenge due to their complex structure and multitude of design parameters. This study tackles such challenge by developing a machine learning based Artificial Neural Network (ANN) model which comprises two sub-ANN models that can work independently for PV and TEG modules or in combination through a cyclic approach for the hybrid PV-TEG system. The model demonstrates remarkable versatility, allowing control over various parameters such as PV coating, device geometry, and environmental conditions. Compared to COMSOL simulations, the ANN model achieves over 97.6 % accuracy with a 6000-fold increase in simulation speed, enabling extensive parameter sweeps and insightful system analysis. Within 18 min, the model conducted a real-time simulation using 8712 weather data entries from Singapore in 2022 and predicted that the hybrid PV-TEG system would generate a total power of 265 kWh/m2, 6.4 % more than that of the standalone PV system with an average system temperature reduction of 7 K. The model's rapid processing capabilities and high accuracy are particularly beneficial for large-scale simulations and practical applications in renewable energy technology.

Structural colour filters can display various colours by selectively transmitting or reflecting a specific wavelength by varying structural parameters rather than material components in the visible region. An important aspect of structural colour is the ability to design a structure that can accurately display the desired colour. While the conventional trial-anderror method requires substantial prior knowledge of the structure together with a number of simulations, deep learning provides an alternative way to inverse design the structural colour with high efficiency and accuracy. In this abstract, we will be discussing the deep learning enabled inverse design of structural colour. By employing the conditional generative adversarial networks (cGAN) to inverse design the structural colour, the one-to-many problem that is often encountered in nanophotonic inverse design is fully tackled. Moreover, we will also explore the possibility of applying this system to the dynamic structural colour inverse design.

Active metamaterials are engineered structures that possess novel properties that can be changed after the point of manufacture. Their novel properties arise predominantly from their physical structure, as opposed to their chemical composition and can be changed through means such as direct energy addition into wave paths, or physically changing/morphing the structure in response to both a user or environmental input. Active metamaterials are currently of wide interest to the physics community and encompass a range of sub-domains in applied physics (e.g. photonic, microwave, acoustic, mechanical, etc.). They possess the potential to provide solutions that are more suitable to specific applications, or which allow novel properties to be produced which cannot be achieved with passive metamaterials, such as time-varying or gain enhancement effects. They have the potential to help solve some of the important current and future problems faced by the advancement of modern society, such as achieving net-zero, sustainability, healthcare and equality goals. Despite their huge potential, the added complexity of their design and operation, compared to passive metamaterials creates challenges to the advancement of the field, particularly beyond theoretical and lab-based experiments. This roadmap brings together experts in all types of active metamaterials and across a wide range of areas of applied physics. The objective is to provide an overview of the current state of the art and the associated current/future challenges, with the hope that the required advances identified create a roadmap for the future advancement and application of this field.

Transition metal dichalcogenides (TMDCs) are an interesting group of 2D materials characterised with a layered structure analogous to graphene and they possess unique electronic and optical properties, especially when in the few- and mono-layer form. Developing scalable techniques for depositing TMDCs is a major challenge which needs to be overcome to fabricate functional devices with these materials. Electrodeposition is an industrially relevant technique that has some key advantages over other conventional deposition methods. It is a low cost and easily scalable technique and could be used for obtaining complex nanoscale features and for depositing over topologically demanding surfaces. Even though the electrodeposition of MoS2 has been achieved both in aqueous and non-aqueous electrolytes, not much progress has been made in the deposition of other TMDC materials. Tungsten based TMDCs such as WS2 and WSe2 are shown to be very promising materials in different applications, however electrodepositing them remains extremely challenging. One of the major obstacles here is developing electrochemically active precursors which are compatible with the electrolyte system and able to deliver both the tungsten and chalcogens to the electrolyte. Controlling and optimizing the deposition process to obtain few- and mono-layer TMDCs is another challenge. In addition, the choice of substrates for deposition is very important, especially for direct growth of ultra-thin TMDCs. Electrodeposition, being a bottom-up deposition method, would benefit from an atomically thin and smooth substrate such as graphene for depositing few- and mono-layer TMDCs. Here we present non-aqueous electroplating as a scalable alternative technique for tungsten-based TMDC deposition, with WS2 and WSe2 as examples. Tailored single source precursors were developed to use in non-aqueous electrolytes. WS2 was electrodeposited from dichloromethane (CH2Cl2) using the [NEt4]2[WS2Cl4] precursor. WSe2 was then electrodeposited from acetonitrile (CH3CN) electrolyte using [WSeCl4] as the precursor. Electrochemical quartz crystal microbalance (EQCM) studies were performed to optimize the deposition process and to probe the mechanism of precursor electrochemistry. Electrochemical deposition parameters were then carefully adjusted to obtain few- and mono-layer TMDCs. Patterned graphene electrodes were used as an atomically thin and smooth platform for the deposition of few- and mono-layer WS2. Few-layer TMDC films obtained on graphene were found to be much smoother than films deposited on other standard substrates such as titanium nitride (TiN) or Pt. These TMDC/graphene structures gave interesting 2D heterostructures which are technologically important for different applications. This work was funded by EPSRC grant references EP/V062689/1, EP/V062387/1 and EP/P025137/1

In the frame of projects funded by the European Commission and the ESA, we developed a new type of Optical Solar Reflector (OSR) that combines the flexibility and easy handling of Second Surface Mirrors with the temperature-variable emittance necessary to ensure both effective radiative cooling in the hot phase and reduced heat losses in the cold phase. The new smart OSR consists of a metamaterial coating deposited on Kapton film. The coating is made of two functional blocks, namely a variable emitter topped by a dielectric solar reflector. The variable emitter is a Metamaterial Perfect Absorber designed for strong and broadband plasmonic resonance absorption in the thermal IR. It consists of a metal back-reflector, a dielectric spacer, and an array of doped VO 2 thermochromic micro-antennas that are switched-off when the temperature drops below the metal-to-insulator transition point. The solar reflector is a wideband dielectric filter made of materials that are transparent across the entire spectrum from the VIS to the thermal IR. All the layers of the two blocks are deposited by standard vacuum techniques, while the array is patterned by Nanoimprint Lithography, a technique that is often performed at the wafer level but allows for up-scaling via roll-to-roll or roll-to-plate production setups. The paper reports on the characterization and testing of samples of size up to 100 mm x 100 mm, at the Beginning of Life and after thermal, humidity, irradiation and handling tests.

Optical Solar Reflectors (OSRs) combine low solar radiation absorption (α) and high broadband infrared emissivity (ε) and are applied to the external surface of spacecraft for its thermal management. Bulk glass OSR tiles are the incumbent, but ultra-lightweight and thin-film flexible OSR coatings are raising considerable interest for both space and terrestrial radiative cooling applications. In this work, a genetic algorithm combined with a transfer matrix method is used for the design and optimization of multimaterial thin-film OSRs for broadband radiative cooling. The algorithm simultaneously optimizes the spectral performance of the OSR at two parts of the wavelength spectrum, solar (0.3–2.5 μm) and thermal infrared (2.5–30 μm). The designed optimized OSR structure consists of 18 alternating layers of three materials, SiN, SiO2, and Ta2O5, on top of an Al mirror backreflector, with a total thickness of only 2.088 μm. The optimized multilayer stack contributes distributed Bragg reflections that reduce the residual solar absorption below that of an uncoated Al mirror. The optimized OSR is demonstrated experimentally on a 150 mm (6 in.) Si wafer and on a flexible polyimide substrate using a production level reactive sputtering tool. The fabricated thin film OSR shows good thermal-optical property with α = 0.11 and ε = 0.75 and achieves a net cooling power of 150.1 W/m2 under conditions of one sun total solar irradiance in space. The ultrathin coating fabricated using hard inorganic materials facilitates its integration onto flexible foils and enables large-scale manufacture of low-cost OSRs for broadband radiative cooling applications.