Copper Bismuth Research Articles

Microwave-assisted preparation of nanocomposite of copper bismuth sulphide containing metallic bismuth (Cu-Bi-S) towards negative electrode for supercapacitor application: An effort at optimizing the relative concentration of copper and bismuth

Microwave-assisted preparation of nanocomposite of copper bismuth sulphide containing metallic bismuth (Cu-Bi-S) towards negative electrode for supercapacitor application: An effort at optimizing the relative concentration of copper and bismuth

Unique Photothermal Materials for Cutting-Edge Interfacial Solar Desalination and Wastewater Purification

Harnessing renewable solar energy for solar desalination shows great promise for addressing freshwater scarcity. However, conventional solar desalination suffers from low photothermal conversion and excessive heat dissipation, limiting its practicality for meeting water demand. Interfacial solar steam generation (ISSG) has emerged to address these limitations, leveraging advances in photothermal absorber materials, structural design, and thermal management. The photothermal material (PTM) plays a crucial role as it facilitates the conversion of solar energy into localized heat energy, leading to water evaporation within a localized high-temperature zone.1 In this talk, we present unique photothermal absorber materials that are not common for ISSG, such as bismuth copper oxysulfide (BiCuSO; BCSO), silicon (Si), and red phosphorus (RP), exhibiting broad light absorption, low thermal conductivity, and high heat localization. 2–5 We employed a mechanochemical activation method to regulate particle size and surface defects simultaneously, thus enhancing the optical, thermal, and photothermal properties. Utilizing the 1D water path architecture, we achieved an outstanding water evaporation rate of 2.2 (photothermal efficiency: 107.9%), 1.77 (96%), and 1.75 kg/m2·h (94.0%) using Si, BCSO, and RP absorber materials, respectively, under 1 sun illumination (100 mW/cm2). Furthermore, our photothermal absorbers demonstrated excellent ion rejection capabilities when subjected to continuous measurement for 50 h with both seawater and industrial wastewater. The emerging interface solar-driven steam generation technology promises to meet future human needs for freshwater, energy, and environmental sustainability. Keywords: Photothermal materials; Mechanochemical activation; Defect control; Interfacial solar desalination; Wastewater purification.

Design and simulation of strong cesium copper–bismuth chloride double perovskite solar cells with an efficiency exceeding 25% for plateau areas

Plateau regions are known for their strong ultraviolet radiation and extended sunlight hours, making them ideal settings for the photovoltaic industry. The development of efficient lead-free perovskite solar cells suitable for high-altitude environments is critical because of the harmful effects of ultraviolet radiation and the toxicity of lead. The cesium copper–bismuth chloride double perovskite with an indirect band gap of 1.36 eV and low toxicity can serve as an ideal absorber for high-efficiency solar cells for ultraviolet and visible absorption. Both density functional theory and a solar cell capacitance simulator were employed to calculate the photoelectric properties of cesium copper–bismuth chloride and optimize device performance. The ideal layer thicknesses of 450 nm for the electron transport layer, 600 nm for the perovskite layer, and 30 nm for the hole transport layer, with respective carrier densities of 1019, 1017, and 1018 cm−3, enabled the optimal device to achieve a short-circuit current of 34.31 mA/cm2, an open-circuit voltage of 0.88 V, a fill factor of 85.3 %, and a power conversion efficiency of 25.62 %, maintaining a fill factor of > 80 % and a power conversion efficiency of > 20 % even at 400 K. Optimized parameters of the absorber and carrier transport layer amplify the built-in electric field and reduce carrier recombination, thereby improving device performance. These findings demonstrate cesium copper-bismuth chloride perovskite solar cells significantly enhance solar energy use in high-altitude environments, providing guidance for the development of other solar cells.

Understanding the electrocatalytic role of magnesium doped bismuth copper titanate (BCTO) in oxygen evolution reaction

Designing high-efficiency electrocatalysts for water oxidation has become increasingly important in the catalysis field owing to its implications for renewable energy production and storage. The production of hydrogen (H2) from water is hampered by the very sluggish kinetics of the water-splitting process. Enhancement of effective oxygen evolution reaction (OER) electrocatalysts is also required to understand the primary barrier to OER. This article investigates the electrochemical activity of magnesium-doped bismuth copper titanate (Mg-BCTO) as an efficient catalyst for the OER in water electrolysis, a critical step in hydrogen production for sustainable energy. The synthesized materials, including various stoichiometries of Mg-doped BCTO, undergo thorough physical and electrochemical characterization using XRD, FT-IR, Raman, SEM, TEM, XPS, CV, EIS, and Tafel polarization analyses. Remarkably, Mg0.1 doped BCTO demonstrates superior performance, achieving a current density of 10 mA cm−2 at a very low overpotential (η10) of 265 mV and with a Tafel slope of 92 mV dec−1. This finding not only highlights the electrocatalytic efficiency of Mg doped BCTO but also positions it as a promising model for the development of highly active and stable water oxidizing catalysts, contributing to the advancement of clean energy technologies.

Enhancement in Photodetector Sensitivity Using All‐Inorganic Perovskite Absorber RbGeI3 and Copper Bismuth Thiocyanate for Superior Charge Transport

This study investigates a photodetector design using the nontoxic, all‐inorganic perovskite material RbGeI3, which is distinguished by its efficient light absorption and excellent photoelectric conversion properties. Incorporating copper bismuth thiocyanate (CBTS) and indium gallium zinc oxide layers, this design enhances charge transport, leading to a photodetector that exhibits exceptional sensitivity across the visible spectrum, along with a peak responsivity of 0.63 A W−1 and a detectivity of 1.37 × 1013 Jones in the near‐infrared (NIR) at 900 nm. The proposed photodetector exhibits wide‐spectrum detection, encompassing both the visible range and the NIR region. These results position RbGeI3 and CBTS as compelling alternatives to traditional photodetector materials such as Si‐Ge, InGaAs, ZnO, and GaN. Validation is achieved through simulations using the SCAPS‐1D simulator, underscoring the potential of perovskite materials for advanced photodetector applications.

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

Uncovering the synthesis of a visible light-driven manganese-doped copper bismuth oxide catalyst for enhanced degradation of dye: Insights into the factors affecting the degradation

In recent times, effluent pollution has had an exceptionally detrimental effect on aquatic life as well as human beings. The management of wastewater has emerged as a formidable undertaking for scientists owing to the existence of organic contaminants. Herein, we synthesized the manganese-doped copper bismuth oxide (Mn0.15Cu0.85Bi2O4) through hydrothermal method and employed them for successfully eliminating complex pollutants. The assessment of the visible light-induced photocatalytic efficacy of the catalyst was performed for the degradation of methyl violet (MV). MV had a degradation of 89.68% when CuBi2O4 was used. However, the degrading rate of the Mn0.15Cu0.85Bi2O4 escalated to 99.18% in 36 min. The rate constant exhibited a rise between 0.0627 and 0.1134 min−1, confirming the effectiveness of the Mn0.15Cu0.85Bi2O4. The effectiveness of the Mn0.15Cu0.85Bi2O4 is due to its superior surface area (51.97 m2/g), which arises from the integration of Mn-ions. Additionally, examining the impact of different reaction variables revealed a substantial correlation with the elimination of MV dye. The potential reason for the deterioration of MV could be attributed to the generation of •OH and O2•− radicals, which was confirmed by radical trapping experiments. The photostability of the generated Mn0.15Cu0.85Bi2O4 catalyst exhibited remarkable characteristics. Ultimately, this study presents a technique for creating effective catalysts for treating wastewater that is both economical and practical.

Effect of Cu/Bi ratio on the photoelectrochemical performance of CuBi2O4/CuO nanocomposite films for CO2 reduction

Abstract Solar energy is free, clean, and virtually limitless; however, its conversion into a storable form presents technological challenges. One avenue towards solar energy utilization is the photoelectrochemical (PEC) reduction of CO2 to one- or two-carbon fuels, employing a semiconductor configured as an electrode. A potential material for this application is the p-type copper bismuth oxide (CuBi2O4) with a band gap capable of visible light absorption and a conduction band edge position suitable for CO2 reduction. In this study, CuBi2O4 nanocomposite films of varying Cu/Bi ratios (0.25, 0.51, 0.68, 0.94, 2.04) were prepared via an electrodeposition-spray deposition-annealing route. Where the Cu/Bi ratio exceeded the stoichiometric value of 0.5, a bilayered film composed of a copper (II) oxide (CuO) phase on top of CuBi2O4 was formed, creating a planar heterojunction between the two oxide layers. With increasing Cu/Bi ratio, the light absorption range of the films broadened due to the CuO phase. Analysis of the photocurrent-potential behavior of the films under visible-light illumination showed a 4–7-fold increase in the photocurrent from an inert electrolyte to a CO2-saturated electrolyte, confirming potential activity for CO2 reduction of the CuBi2O4/CuO films. A higher Cu/Bi ratio resulted to an improved charge separation efficiency, enhancing the photocurrent generation. However, the transient photocurrent response of the films showed a 70-80% decrease in the photocurrent after only 15 mins of testing. When tested in an electrolyte with an electron scavenger, the percent decrease was lowered to <10%, indicating that the instability of the films resulted from poor interfacial kinetics. While the CuBi2O4/CuO nanocomposite films can accomplish CO2 reduction, further strategies to improve their efficiency and stability are needed to realize practical application.

Structural and optoelectronic studies of BiCuOS semiconductor: A potential photoconverter

As a p-type semiconductor, Bismuth copper oxysulfide (BiCuOS) with a narrow bandgap has exceptional absorption characteristics in the visible and near-infrared spectral regions, which have good application prospects for optoelectronic devices. A simple hydrothermal technique is successfully employed for the complicated material synthesis. The desired phase formation of the material has been investigated by varying the reaction time in the procedure, and it is observed to be crucial in maximizing the yield of this material. The scanning electron microscope (SEM) and transmission electron microscope (TEM) are utilized to analyze the morphological and lattice arrangements of the prepared sample. The photodetection performance of the material is assessed through the fabrication of a self-powered p-n heterojunction photodetector with grown n-type ZnO. At self-powered conditions, the device showed a better spectral responsivity of 118 μA/W,detectivity of around 8.27 × 107 Jones, and linear dynamic range (LDR) of 5.7 Hz. The proposed interface of oxychalcogenide semiconductor is anticipated to broaden the research on its improvement and usage in various optoelectronic applications.

Electrochemically-induced metal–oxygen bond Cu(II)-[rad]SO5− on novel CuBi2O4 anode for efficient peroxymonosulfate activation

Transition metal oxide catalysts had the limitation of a slow electron transfer rate in activating peroxymonosulfate (PMS) during wastewater treatment. In this work, we developed a novel copper bismuthate (CuBi2O4) anode using a catalyst drop casting method to efficiently activate PMS through electrochemically induced metal–oxygen bonds for herbicide prometon (PMT) degradation. The PMT removal rate in the EC/CuBi2O4 anode/PMS system was 74.60 %, which was much greater than the simple superposition of CuBi2O4 catalyst-activated PMS alone (4.88 %) and FTO anode electrically activated PMS (32.15 %). The CuBi2O4 fixed on the anode surface accelerated the electron transfer efficiency between the interface employing the electric field, showing stronger PMS activation performance than the equivalent three-dimensional particle electrode system. The free radical quenching experiments illustrated that the degradation of PMT mainly proceeded through the free radical oxidation pathway dominated by SO4− and OH. In the EC/CuBi2O4 anode/PMS system, the traditional Cu+/Cu2+ cycle did not dominate the activation of PMS in the CuBi2O4 anode reaction. Raman experiment and open circuit potential results proved that the introduction of an electric field caused PMS to form the metal–oxygen bond Cu(II)-SO5− at the CuBi2O4 anode interface, and converted it into activated state PMS (PMS*), accelerating the interface electron transfer. The PMS* was more readily further activated by electrons and promoted water dissociation to form OH for pollutants degradation. The EC/CuBi2O4 anode/PMS system manifested stable purification performance for COD and emerging pollutants in high-salt pesticide wastewater, coupled with its superior economic benefits, possessing broad application prospects.

Rational Construction of Bi2CuO12Se4 and VGCFs@Fe2O3 Composite Electrodes for High-Performance Semi-Solid-State Asymmetric Supercapacitors.

Recently, supercapacitors (SCs) are extensively explored as effective energy storage devices. Specifically, asymmetric SCs are being developed to enhance energy density using suitable materials with favorable nanostructures. This study describes the construction of a bismuth copper selenite (BCS-200) working electrode with an ultrathin nanosheet(UTNS) architecture. This morphology is achieved using a low-cost electrodeposition (ED) method, followed by annealing. The impact of ED time on the development of morphology is studied by synthesizing comparative electrodes simultaneously. The optimized BCS-200 electrode prepared with a deposition time of 200 s shows higher specific capacity/capacitance (Cs/Csc) values of 330.9 mAh g-1/2206.6 F g-1 than the other synthesized electrodes (BCS-100, BCS-150, BCS-250, and BCS-300). Besides, a vapor-grown carbon fiber (VGCF)-added Fe2O3 composite coated on nickel foam (NF) is developed as a negative electrode. The VGCFs@Fe2O3/NF electrode exhibits the (Cs/Csc) values of 183.5 mAh g-1/734.4 F g-1, which is associated with ultra-high cycling stability. In addition, the fabricated BCS-200 and VGCFs@Fe2O3/NF electrodes are combined to construct a wearable semi-solid-state asymmetric SC (SSASC) with an energy density (Ed) of 20.5Wh kg-1 and a cycling stability of 91.7% over 40000 charge/discharge cycles. Furthermore, the real-time applicability of the SSASC is verified by powering it in practical applications.

Spinel CuBi2O4 integrated with boron nitride hexagons for a sensitive electro-analytical quantification of environmental organic pollutants

As organic pollutants are non-biodegradable, they pose a threat to the ecology and human health. Metol (MTL) is one of the most serious pollutants that gush into water sources. In this work demonstrates, a hydrothermal synthesized CuBi2O4 and ultrasonication approach for the construction of the Copper bismuth oxide/hexagonal boron nitride nanocomposite (CuBi2O4/hBN). Therefore, this consistent structure which enhance to strong interfacial interactions between the CuBi2O4 and hBN and also which facilitated the fast electron transfer efficiency in addition the physical and electrochemical characters of the CuBi2O4/hBN was characterize with supported by XRD, XPS, FE-SEM, HR-TEM, CV and DPV analysis. As a consequence, CuBi2O4/hBN/GCE surface modified electrode possessed a LOD of MTL 0.0052 µM at the sensitivity of 1.976 µA µM−1 cm−2 with 0.001 µM to 1987 µM linear rage. Furthermore, the feasibility of CuBi2O4/hBN/GCE to determine the MTL in the environmental water samples for instance pond, river, and tap water delivered a maximum recovery range about 97–99 % towards the detection of MTL. Therefore, CuBi2O4/hBN electrode material to attain superior electrochemical performances for the detection of MTL.

Oxygen-enriching triphase platform for reliable sensing of femtomolar Alzheimer’s neurofilament lights

Accurate quantification of neurofilament lights (NfLs), a prognostic blood biomarker, is highly required to predict neurodegeneration in the presymptomatic stages of Alzheimer’s disease. Here, we report self-oxygen-enriching coral structures with triphase interfaces for the label-free photocathodic detection of NfLs in blood plasma with femtomolar sensitivities and high reliability. In conventional photocathodic immunoassays, the poor solubility and sluggish diffusion rate of the dissolved oxygen serving as electron acceptors have necessitated the incorporation of additional electron acceptors or aeration procedures. To address the challenge, we designed the coral-like copper bismuth oxides (CBO) with robust solid–liquid–air contact boundaries that enrich the interfacial oxygen levels without an external aeration source. By optimally assembling the perfluorododecyltrichlorosilane (FTCS) and platinum (Pt) co-catalysts into the silver-doped CBO (Ag:CBO), the stable solid–liquid–air contact boundaries were formed within the sensor interfaces, which allowed for the abundant supply of air phase oxygen through an air pocket connected to the atmosphere. The Pt/FTCS-Ag:CBO exhibited the stable background signals independent of the dissolved oxygen fluctuations and amplified photocurrent signals by 1.76-fold, which were attributed to the elevated interfacial oxygen levels and 11.15 times-lowered mass transport resistance. Under the illumination of white light-emitting diode, the oxygen-enriching photocathodic sensor composed of Pt/FTCS-Ag:CBO conjugated with NfLs-specific antibodies precisely quantified the NfLs in plasma with a low coefficient of variation (≤2.97%), a high degree of recovery (>97.0%), and a limit of detection of 40.38 fg/mL, which was 140 times lower than the typical photocathodic sensor with diphase interfaces.

Numerical modelling of CuBi2O4 thin film solar cells with SCAPS-1D: Bridging the gap ideal and non-ideal conditions

Several simulation studies have been conducted in copper bismuth oxide (CuBi2O4) based solar cells (SCs) using SCAPS-1D simulator, demonstrating a high photoconversion efficiency (PCE) of up to 33 % under ideal conditions. The introduction of non-ideal conditions such as resistive losses, optical, and recombination losses could provide the actual performance of the SCs. In this letter, we applied all nonideal conditions to the SCs structure consisting of Mo/CuBi2O4/TiO2/ITO/Al with varied thicknesses of absorber layer of CuBi2O4 from 50 nm to 2 µm and evaluated the photovoltaic (PV) parameters and PCE of SCs. Under ideal conditions, cells exhibited a PCE of 31.23 % and 3.55 % with an absorber layer thickness of 2000 nm and 50 nm, respectively. The introduction of nonideal conditions with an absorber layer thickness of 50 nm, exhibited a drastic reduction of PCE from 3.55 to 0.46 % and other PV parameters such as open circuit voltage (Voc) from 1.19 to 1.04 V, short circuit current density (Jsc) from 4.27 to 0.77 mA/cm2, and fill factor (FF) from 69.40 to 56.42 %. The increase in thickness of the absorber layer further to 2000 nm did not improve the PCE of SCs.

Photoelectrocatalytic Reduction of Cr(VI) in Wastewater with a CuBi2O4 Thin Film Photocathode

Photoelectrocatalytic approaches show promise for contaminate removal in wastewater through redox reactions. However, the direct treatment of very low concentration heavy metals is a challenging task. Copper bismuth oxide is considered as a potential photocathode material due to its appropriate bandgap width and excellent light absorption properties. In this work, we utilize copper bismuth oxide photoelectrodes with micrometer-scale pores to achieve the efficient and complete reduction of micromolar-level hexavalent chromium(VI) in wastewater. In a continuous 180 min experiment, the reduction rate of 5 µM hexavalent chromium reached 97%, which is an order lower than the drinking standard. Such a process was facilitated by the unique hierarchical microstructure of the oxide thin film and the porous morphology. On the other hand, the structural evolution during the operation was analyzed. A surface passivation was observed, suggesting the possible long-term practical application of this material. This study serves as an important reference for the application of photoelectrocatalysis in addressing Cr(VI) pollution in wastewater, with implications for improving water quality and environmental protection.

Influence of Deposition Potential on Electrodeposited Bismuth–Copper Oxide Electrodes for Asymmetric Supercapacitor

AbstractThe modern research reported the simplest low–cost synthesis of Bismuth–Copper oxide (Bi2CuO4) with spruce–leaf–like morphology and its applications in supercapacitor devices. Bi (NO3)3 . 5H2O was used as a precursor during an electrodeposition (ED) method to create the spruce–leaf–like Bi2CuO4 electrode. XRD, XPS, FE−SEM, EDX, and TEM were used to characterize the structures and morphologies of the synthesized materials, while CV, CP, and EIS were used to determine their electrochemical characteristics. The Bi2CuO4 phase was confirmed by XRD patterns, and electrochemical testing demonstrated that the material had better rate capability and an SC of 431.2 F/g at a scan rate of 2 mV/s. After 5,000 cycles, it retained 81.4 % of its energy. Additionally, the maximum SC that was attained by the created asymmetric solid–state device ASSD (Bi0.6 Vǀǀ1 M PVA−KOHǀǀAC) was 73.7 F/g. The energy density was 55.3 Wh/Kg at a power density of 4570 W/Kg. The exceptional electrochemical performance of Bi2CuO4 thin film electrodes recommends it has a promising material.

Novel Spatially Asymmetric Copper Bismuthate-Mediated Augmentation of Energy Conversion to Realize "Three-Step" Tumor Suppression.

The generally undesirable bandgap and electron-hole complexation of inorganic sonosensitizers limit the efficiency of reactive oxygen species (ROS) generation, affecting the effectiveness of sonodynamic therapy (SDT). Comparatively, the novel polyvinylpyrrolidone-modified copper bismuthate (PCBO) sonosensitizers are manufactured for a "three-step" SDT promotion. In brief, first, the strong hybridization between Bi 6s and O 2p orbitals in PCBO narrows the bandgap (1.83eV), facilitating the rapid transfer of charge carriers. Additionally, nonequivalent [CuO4]6- layers reduce crystal symmetry, confer PCBO unique piezoelectricity, and improve electron-hole separation under ultrasonic (US) excitation. This allows PCBO to convert US energy into chemical energy to produce ROS, achieving the accumulation of abundant ROS, resulting in apoptosis and tumor suppression. Concurrently, PCBO also acts as a glutathione scavenger to reduce tumor antioxidant capacity and improve efficacy. To the best of authors understanding, this study reveals PCBO as an innovative piezoelectric sonosensitizer and provides a meaningful paradigm for designing energy conversion strategies for tumor suppression.

Boosting piezo-photocatalytic activity in CuBi2O4/NaNbO3 by coupling it with PVDF for organic pollutant degradation

This work reports a piezo-photocatalytic film, which is easily synthesised and retrievable from water with an environmentally friendly composition exhibiting higher reaction kinetics for degradation of dye using polyvinylidene-fluoride (PVDF), copper bismuth oxide (CuBi2O4) and sodium niobate (NaNbO3). XRD confirmed the structure of CuBi2O4 and NaNbO3, and FTIR was used to confirm β-PVDF, while HR-SEM was used to study morphology. The prepared film displays excellent stability in piezo-photocatalytic conditions. It degrades rhodamine B (RhB) with 98 % efficiency within 30 min in piezo-photocatalysis mode and 113 times faster than CuBi2O4/NaNbO3. This enhanced performance is due to the synergistic piezocatalytic effect of PVDF and NaNbO3. Further, to understand the catalytic nature of the ultrasonic-induced piezo-photocatalytic effect for dye degradation, scavenger studies were performed to identify the radicals generation. Reusability tests revealed no loss in efficiency for five consecutive runs. The strategy outlined here can be used to treat industrial effluents containing various complex dyes.

Improved Conductivity and in Situ Formed Heterojunction via Zinc Doping in CuBi2O4 for Photoelectrochemical Water Splitting.

As a photocathode with a band gap of about 1.8 eV, copper bismuthate (CuBi2O4) is a promising material for photoelectrochemical (PEC) water splitting. However, weak charge transfer capability and severe carrier recombination suppress the PEC performance of CuBi2O4. In this paper, the conductivity and carriers transport of CuBi2O4 are improved via introducing Zn2+ into the synthesis precursor of CuBi2O4, driving a beneficial 110 mV positive shift of onset potential in photocurrent. Detailed investigations demonstrate that the introduction of an appropriate amount of zinc leads to in situ segregation of ZnO which serves as an electron transport channel on the surface of CuBi2O4, forming heterojunctions. The synergistic effect of heterojunctions and doping simultaneously promotes the charge transfer and the carrier concentration. OCP experiment proves that ZnO/Zn-CuBi2O4 possesses better charge separation; the Mott-Schottky curve shows that the doping of Zn significantly enhances the carrier concentration; carrier lifetime calculated from time-resolved photoluminescence confirms faster extraction of carriers.

Progress and applications of (Cu–)Ag–Bi–I semiconductors, and their derivatives, as next-generation lead-free materials for photovoltaics, detectors and memristors

The search for efficient but inexpensive photovoltaics over the past decade has been disrupted by the advent of lead-halide perovskite solar cells. Despite impressive rises in performance, the toxicity and stability concerns of these materials have prompted a broad, interdisciplinary community across the world to search for lead-free and stable alternatives. A set of such materials that have recently gained attention are semiconductors in the CuI–AgI–BiI3 phase space and their derivatives. These materials include ternary silver bismuth iodide compounds (Ag aBi bI a+3 b), ternary copper bismuth iodide Cu–Bi–I compounds and quaternary Cu–Ag–Bi–I materials, as well as analogues with Sb substituted into the Bi site and Br into the I site. These compounds are comprised of a cubic close-packed sub-lattice of I, with Ag and Bi occupying octahedral holes, while Cu occupies tetrahedral holes. The octahedral motifs adopted by these compounds are either spinel, CdCl2-type, or NaVO2-type. NaVO2-type Ag aBi bI a+3 b compounds are also known as rudorffites. Many of these compounds have thus far demonstrated improved stability and reduced toxicity compared to halide perovskites, along with stable bandgaps in the 1.6–1.9 eV range, making them highly promising for energy harvesting and detection applications. This review begins by discussing the progress in the development of these semiconductors over the past few years, focusing on their optoelectronic properties and process–property–structure relationships. Next, we discuss the progress in developing Ag–Bi–I and Cu–Bi–I compounds for solar cells, indoor photovoltaics, photodetectors, radiation detectors and memristors. We conclude with a discussion of the critical fundamental questions that need to be addressed to push this area forward, and how the learnings from the wider metal-halide semiconductor field can inform future directions.