Metal halide perovskites (MHPs) are emerging semiconductors with unique optoelectronic properties promising for highly rewardable applications. Water and polar solvents instability hinders the introduction of MHPs into CMOS technology infrastructure and is the main challenge for patterning and integration into electronic systems. Recently, dry etching in combination with standard lithography was demonstrated as a viable technology to address the problem. In this work, we investigate the dry etching of MHPs using argon (Ar) ion milling. Simulated etch rates using Ziegler's model are validated with experimental measurements. Assuming a linear sum of elemental sputtering yields results in total sputtering yield values for complex MHPs (CsPbIBr2, CsPbBr2Cl) that agree well with experimental data. Interestingly, ignoring the organic part of the hybrid halide perovskite MAPbI2Br gives a valid estimation of the sputtering yield. At a typical processing ion energy of 700 eV, Ar milling achieves rates of approximately 1-2 nm/s across various perovskite compositions. Photodetectors (PDs) fabricated under optimized etching conditions retain typical photoresponse, demonstrating the device functionality can be preserved after etching.

Colloidal quantum dots (QDs) have become firmly established in the display market, yet many relevant QD compositions contain heavy metals whose concentrations are regulated in consumer products. Accurate characterization of hazardous metal content in QD displays is therefore essential but challenging due to their complex multilayer structure. Here, a commercially available QD display film is analyzed using complementary techniques, with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as the central tool. The film contains CdSe-based core-shell QDs as the green component and, for the first time in a commercial product, lead halide perovskite (LHP) QDs as the red component. Principal component analysis combined with k-means clustering enabled the extraction of bead-like pixel populations corresponding to CdSe and LHP QDs, with classification accuracies of 84% and 95%, respectively. This approach establishes a pathway toward advanced analytical strategies for assessing the regulatory compliance of commercial QD displays.

The key asset of X-ray medical imaging lies in detecting fine features, governed by detector spatial resolution and high detection efficiency. Metal halide perovskites are emerging semiconductors with potential to exceed state-of-the-art direct-conversion and scintillation materials, featuring '10 lp mm-1 spatial resolution. Yet, integrating high-quality perovskite layers with readout arrays remains challenging. Here, we demonstrate fabrication of thick, large-grain polycrystalline CsPbBr3 films by melting directly on pixelated glass interposers. The obtained array detectors show a remarkable 20 lp mm-1 intrinsic spatial resolution at MTF20, detection efficiency of 75.4%, and a low noise-equivalent dose of '46 photons for 22 keV X-rays under low reverse bias. These features enable unprecedented charge-integrating performance with 20% detective quantum efficiency at the Nyquist frequency. Single-pixel devices show single-photon counting of gamma-radiation, resolving the 60 keV 241Am peak. Melt-grown CsPbBr3 films thus uniquely combine detection efficiency, scalability, and cost-effectiveness for next-generation low-dose, high-resolution X-ray imaging.

Lead halide perovskites represent a promising class of semiconductor materials, notable for their unique optoelectronic properties. However, their application in advanced semiconductor devices, such as CMOS image sensors, photonic integrated circuits, and memristors, requires the development of precise, perovskite-specific patterning processes compatible with standard cleanroom fabrication. Here, we introduce several key innovations enabling standard microfabrication with lead halide perovskites. First, surface passivation with sorbitan laurate effectively seals the perovskite grain boundaries, enabling the use of standard photoresists (e.g., AZ1518) and aqueous developers on complete device stacks. Furthermore, a modified phosphoric acid etchant, incorporating phenylbutylammonium bromide (PBABr), facilitates the selective etching of transparent conductive oxides (TCOs) such as ITO directly atop the perovskite stack without significant degradation of the active layer. Finally, SF6 plasma treatment, using the patterned TCO as a hard mask, selectively converts perovskite in the interpixel gaps into non-photoactive PbFxBr2-x, effectively suppressing lateral cross-talk. Utilizing this integrated fabrication strategy, we successfully fabricated and characterized a 400 × 400 pixel perovskite CMOS image sensor, where the well-defined pixels are essential for high spatial resolution and sensor performance. Our results establish a pathway for the development of high-performance (opto)electronic devices based on lead halide perovskites integrated via standard semiconductor processing methods.

This paper presents a 400 x 400 perovskite image sensor incorporating time-efficient multiple sampling (TEMS) and adaptive resolution (AR) techniques. The proposed TEMS achieves noise reduction with minimal frame rate penalty compared to conventional multiple sampling (MS), while AR dynamically adjusts the resolution of each column ADC according to signal level and the focused imaging region, thereby minimizing power consumption. A readout circuit for a prototype is fabricated in a 180nm CMOS process, achieving 41% lower noise with 4-times TEMS compared to single sampling, a 36% higher frame rate than conventional 4-times MS, and 24% lower power consumption with AR. A perovskite photodetector array is monolithically integrated on the CMOS readout chip through post-processing steps.

Over the past decade, lead halide perovskites (LHPs) have become a vibrant thrust in the field of direct conversion X-ray and gamma-ray radiation detectors, offering promising cost-effective and robust alternatives to traditional semiconductors. This review article chronicles the significant strides made since the inception of this field, emphasizing the material, structural, and functional advancements. It begins with an overview of the fundamental properties of perovskites that render them suitable for high-energy radiation detection, such as their high atomic number, prominent charge carriers' mobility and lifetime, and high resistivity. The review highlights key developments in material synthesis and processing techniques that have enhanced these detectors' stability, efficiency, and scalability. Furthermore, the review discusses the evolution of device architectures from single-channel photodiodes to complex multi-pixel arrays for imaging applications. The conclusion is focused on the remaining challenges that hamper the immediate progression of LHP radiation detectors to higher technology levels. This review is intended as a resource for academic researchers and industry stakeholders, summarizing the first decade of LHP detectors and forecasting the trajectory of this promising field, while remembering that forecasting the future trajectory, though challenging, is guided by current technological trends.

Perovskite photodetectors have emerged as a potential replacement for silicon photodiodes in modern cameras due to their high sensitivity to visible light and ability to be easily integrated into existing electronics. However, the use of perovskite photodetectors in conventional CMOS image sensors requires the application of reverse bias, which can lead to unstable detector performance due to ion migration effects. In this article, we propose a new approach that involves the application of forward voltage pulses to attenuate ion migration while still enabling the capture of photocurrent under reverse bias. Our results show that using this technique after each cycle of signal integration allows for stable operation of perovskite photodetectors for over 180 h, while applying a constant reverse bias leads to degradation within just 10 min. Additionally, we demonstrate stable imaging using alternating voltage and 8 × 8 crossbar arrays of perovskite photodetectors.

A novel class of semiconducting compounds, metal‐halide perovskites (MHPs), has emerged as a versatile platform for advanced optoelectronic device architectures, offering a unique combination of exceptional physical properties and facile processing. In this study, we present a monolithic high‐speed photodetector capable of directly sensing the time delay between two light pulses with a temporal resolution of at least 170 ps, corresponding to a light propagation distance of ~5 cm—making it well suited for Light Detection and Ranging (LiDAR) applications. This outstanding time resolution is achieved through a signal‐balancing detection scheme that effectively overcomes the limitations of conventional photodetectors, whose response speed is inherently limited by charge‐carrier lifetime and transit time. The device exhibits an exceptionally low noise spectral density, comparable to that of state‐of‐the‐art silicon photodiodes. The fully symmetric device stack comprises a crystalline CsPbBr 3 absorber layer tens of microns thick, fabricated via a confined melt process. Comprehensive electro‐optical characterization reveals charge‐carrier lifetimes and mobilities on both microscopic and macroscopic length scales, using transient photoluminescence, time‐resolved photocurrent, time of flight, and terahertz pump–probe spectroscopy. The CsPbBr 3 layer exhibits charge‐carrier lifetimes exceeding 100 ns, a microscopic electron–hole mobility of 15 ± 1 cm 2 V −1 s −1 , and a macroscopic non‐dispersive hole mobility of 8.5 cm 2 V −1 s −1 . image

Modern colour image sensors face challenges in further improving sensitivity and image quality because of inherent limitations in light utilization efficiency1. A major factor contributing to these limitations is the use of passive optical filters, which absorb and dissipate a substantial amount of light, thereby reducing the efficiency of light capture2. On the contrary, active optical filtering in Foveon-type vertically stacked architectures still struggles to deliver optimal performance owing to their lack of colour selectivity, making them inefficient for precise colour imaging3. Here we introduce an innovative architecture for colour sensor arrays that uses multilayer monolithically stacked lead halide perovskite thin-film photodetectors. Perovskite bandgap tunability4 is utilized to selectively absorb the visible light spectrum's red, green and blue regions, eliminating the need for colour filters. External quantum efficiencies of 50%, 47% and 53% are demonstrated for the red, green and blue channels, respectively, as well as a colour accuracy of 3.8% in ΔELab outperforming the state-of-the-art colour-filter array and Foveon-type photosensors. The image sensor design improves light utilization in colour sensors and paves the way for the next generation of highly sensitive, artefact-free images with enhanced colour fidelity.

Fast neutron imaging is a promising technique for visualizing objects containing dense, mixed light-and-heavy-elements materials, such as combustion engines, nuclear fuel assemblies, and fossils, where X-rays and thermal neutrons are ineffective. However, the limited efficiency of current detection technologies hinders their widespread adoption. Recoil proton detection using two-component scintillator screens composed of doped zinc sulfide (ZnS) microparticles in polypropylene (PP) remains the standard imaging tool due to the high light yield of ZnS. The efficiency is, however, restricted by the low volumetric fraction of ZnS, which cannot be increased without causing excessive light scattering and loss of resolution, while PP is still needed for substantial interaction with neutrons. In this work, a monocompound metal halide tetraphenylphosphonium manganese bromide (TPP2MnBr4) scintillator is explored as an alternative, exhibiting 1.5 times higher light output and fourfold higher light yield than conventional ZnS-based scintillators. This improvement arises from superior recoil proton energy utilization in the homogeneous structure of TPP2MnBr4 compared to the heterogeneous composition of PP/ZnS. Imaging tests show spatial resolution of around one line pair per millimeter, matching commercial PP/ZnS screens. These results indicate that TPP2MnBr4 scintillator can reduce exposure time and improve image quality, paving the way for efficient, high-resolution neutron imaging technologies.

Lead halide perovskites (LHPs) have attracted significant attention for their exceptional optoelectronic properties, positioning them as prime candidates for next‐generation electronics such as photodetectors (PDs), lasers, light‐emitting diodes (LEDs), and memristors. However, integrating these materials into device architectures with CMOS‐compatible technologies in a simple manner remains a critical challenge. This study introduces a universal method leveraging standard lithographic patterning to fabricate high‐performance LHP PDs for red (R), green (G), and blue (B) color detection separately. Through optimization of the device stack and etching conditions, perovskite PDs are pixelated using a one‐step lithography and pulsed argon (Ar) milling process. The resulting devices exhibit typical perovskite PD responsivity (0.3 A W −1 ), low dark current density (less than 10 −6 mA cm −2 ), high detectivity (over 10 13 Jones), and short fall time (sub‐20 ns without bias). This approach not only enhances device performance but also paves the way for scalable production of perovskite‐based optoelectronic devices. The versatility and effectiveness of this method highlight its potential for broad applicability in CMOS‐compatible perovskite‐based image sensor technology.

Semiconductor nanocrystals are widely investigated as tunable quantum emitters due to their composition-, size- and shape-dependent optical properties, and they find applications in various optoelectronic devices, including lasers. However, in compact films, insulating ligands often limit heat and charge transport. Improving the heat management, for example, by removing ligands, can significantly enhance the operational stability at high excitation densities required for laser devices. Here, we report the synthesis, structural characterization, and stable high optical gain of ligand-free nanocrystalline thin films obtained through single-source thermal evaporation of CsPbX3 (X = Cl, Br). This deposition method is robust, scalable, and compatible with industrial processes. A slow postdeposition crystallization process under nitrogen yields compact, smooth, and optically uniform thin films with nanocrystalline grains with weakly confined optical features and pronounced excitonic resonances. The films show composition-tunable (430-545 nm), low-threshold (ca. 2 μJ cm-2) amplified spontaneous emission, with a high net modal gain of 890 cm-1 measured for the pure CsPbBr3 composition. Due to the enhanced heat dissipation enabled by the optimized film morphology, the operation stability under ambient conditions surpasses 180 million laser shots (i.e., 5 h of continuous operation), with merely ∼8% degradation, indicating that thermally evaporated perovskite thin films are promising optical gain media for room-temperature lasing applications.

Colloidal III-V arsenide quantum dots (QDs) are promising low-toxicity, solution-processable materials for near-infrared optoelectronics, yet their development has been constrained by the scarcity of suitable precursors and proneness to oxidation. Existing routes either rely on highly reactive but toxic, pyrophoric group-14-substituted arsines, or on safer aminoarsines that require in situ reduction and cause staggered rather than a single burst nucleation. We introduce aluminum tris[bis(mesitoyl)arsenide] as a nonpyrophoric and air-stable precursor that, upon nucleophilic attack, directly delivers the formally As3- species. Using this precursor, we synthesized 2.3-4.6 nm large InAs QDs and 2-5.5 nm large Cd3As2 QDs with photoluminescence tunable in the 800-2250 nm range. These results establish aluminum tris[bis(mesitoyl)arsenide] as a versatile precursor, enabling safe and controlled syntheses of various arsenide QDs.

Modern clinical diagnostics significantly rely on X-ray medical imaging detectors, which play a key role in obtaining high-quality images while ensuring patient radiation exposure adheres to the "as low as reasonably achievable" principle. The last decade has seen a renewed exploration of promising materials for X-ray detection, foremost focusing on lead-based perovskites and other metal halides as direct-conversion semiconductors and scintillators. However, the reported performance characteristics, particularly X-ray sensitivity and the limit of dose rate detection, are often incomplete or misleading for assessing the practical utility of materials. This perspective surveys various approaches to the X-ray detector characterization of emerging materials, specifically focusing on Detective Quantum Efficiency within the context of low-dose medical imaging applications. Guidelines are provided for choosing, estimating, and presenting the relevant figures of merit, encompassing Detection Efficiency, Noise Equivalent Dose, response time, and spatial resolution, accompanied by ready-to-use computational tools, including a MATLAB application, a Mathcad worksheet, and an interactive website.

The last decade has seen a renewed exploration of semiconductor materials for X-ray detection, foremost focusing on lead-based perovskites and other metal halides as direct-conversion materials and scintillators. However, the reported performance characteristics are often incomplete or misleading in assessing the practical utility of materials. This Perspective offers guidelines for choosing, estimating and presenting the relevant figures of merit. We also provide ready-to-used tools for calculating these figures of merit: MATLAB application, Mathcad worksheet and a website. The X-ray detectors for medical imaging are at focus for their increasing societal value and since they bring about the most stringent requirements as the image shall be acquired at as low as reasonably attainable (i.e. ALARA principle) dose received by the patient.

A major thrust of medical X-ray imaging is to minimize the X-ray dose acquired by the patient, down to single-photon sensitivity. Such characteristics have been demonstrated with only a few direct-detection semiconductor materials such as CdTe and Si; nonetheless, their industrial deployment in medical diagnostics is still impeded by elaborate and costly fabrication processes. Hybrid lead halide perovskites can be a viable alternative owing to their facile solution growth. However, hybrid perovskites are unstable under high-field biasing in X-ray detectors, owing to structural lability and mixed electronic–ionic conductivity. Here we show that both single-photon-counting and long-term stable performance of perovskite X-ray detectors are attained in the photovoltaic mode of operation at zero-voltage bias, employing thick and uniform methylammonium lead iodide single-crystal films (up to 300 µm) and solution directly grown on hole-transporting electrodes. The operational device stability exceeded one year. Detection efficiency of 88% and noise-equivalent dose of 90 pGy air are obtained with 18 keV X-rays, allowing single-photon-sensitive, low-dose and energy-resolved X-ray imaging. Array detectors demonstrate high spatial resolution up to 11 lp mm −1 . These findings pave the path for the implementation of hybrid perovskites in low-cost, low-dose commercial detector arrays for X-ray imaging.

The long search for nontoxic alternatives to lead halide perovskites (LHPs) has shown that some compelling properties of LHPs, such as low effective masses of carriers, can only be attained in their closest Sn(II) and Ge(II) analogues, despite their tendency toward oxidation. Judicious choice of chemistry allowed formamidinium tin iodide (FASnI3) to reach a power conversion efficiency of 14.81% in photovoltaic devices. This progress motivated us to develop a synthesis of colloidal FASnI3 NCs with a concentration of Sn(IV) reduced to an insignificant level and to probe their intrinsic structural and optical properties. Intrinsic FASnI3 NCs exhibit unusually low absorption coefficients of 4 × 103 cm-1 at the first excitonic transition, a 190 meV increase of the band gap as compared to the bulk material, and a lack of excitonic resonances. These features are attributed to a highly disordered lattice, distinct from the bulk FASnI3 as supported by structural characterizations and first-principles calculations.