ABSTRACT Zn‐based quantum dots (QDs) have been regarded as the most promising Cd‐free candidates for blue‐emitting applications. ZnSe QDs exhibit an ultra‐narrow full width at half maximum (FWHM), high photoluminescence quantum yield (PLQY), and excellent environmental stability, making them ideal for blue‐violet emitters. ZnSe/ZnS core–shell structures have achieved a near 100% PLQY, thereby enabling high performance QDs light‐emitting diode (QLED) with an external quantum efficiency (EQE) of 13.6% at 443 nm. In order to extend the luminescence range for blue display, ZnSeTe QDs has been developed by doping Te ions into ZnSe. Currently, ZnSeTe QLEDs have achieved a maximum EQE of 24.7% at 460 nm, comparable to state‐of‐the‐art Cd‐based QLEDs, and a half‐lifetime of nearly 30 000 h (@100 cd/m2), demonstrating exceptional commercial potential. This review focuses on blue‐emitting ZnSe(Te) QDs, offering a comprehensive overview of recent advances. It presents a systematic discussion on ZnSe(Te) QDs, beginning with material properties and synthesis methods, following by the optimization strategies. Subsequently, the construction of LED devices is analyzed through improvements in both the emitting layer and carrier transport layers. Finally, the challenges in the development of ZnSe(Te) QLEDs are identified, and potential solutions are proposed, aiming to promote further advancements and accelerate their commercialization.

CuInS₂ (CIS) near-infrared (NIR) quantum dots (QDs) are a promising class of colloidal nanocrystals due to their low toxicity and unique optical properties, making them ideal for a variety of applications. However, their stability, particularly against photoinduced quenching, has been insufficiently studied. Shell doping has emerged as an effective strategy to enhance stability, but existing shell growth methods often lead to significant cation exchange at the core-shell interface, causing an undesirable blue shift in the emission peak and reducing the economic value of NIR emissions. In this study, we introduce a simple and robust shell doping strategy to form a rigid ZnS shell doped with Al, aiming to improve the stability of QDs while preserving their NIR emission. Al doping increases the shell bandgap, enhances quantum confinement, and passivates trap states at the core-shell interface, synergistically boosting optical performance and stability under high excitation power densities. The resulting CIS/AlZnS (CIS/AZS) core/shell QDs exhibit a NIR emission peak at 970 nm, a photoluminescence quantum yield (PL QY) of 95.2%, and significant improvements in stability, including a 100% increase in thermal stability and a 150% enhancement in resistance to photoinduced quenching.

Lead-free perovskites are promising for photodetector applications due to their excellent optoelectronic properties and low toxicity. However, the performance of perovskite-based photodetectors is often limited by defects in the films, leading to non-radiative recombination and reducing carrier mobility. In this work, we report the significant performance enhancement of CsBi3I10 perovskite photodetectors through Mn doping. Mn-doped CsBi3I10 films were prepared in an air environment, which still shows good stability. Structural and photoelectronic characterizations confirm that Mn doping effectively passivates defects, suppresses non-radiative recombination, and reduces the dark current. Furthermore, this doping strategy leads to a remarkably weak light detection feature and high reproducibility of the photodetectors. The optimized device achieves a responsivity of 1.11 A/W, a specific detectivity of 1.62 & times; 1012 Jones, a fast response time of 4.53 (rise) and 1.47 mu s (decay) under 650 nm illumination. Considering its special response spectrum and fast response under low-light conditions, a blood oxygen saturation monitoring system was successfully built on the Mn-doped CsBi3I10 perovskite, achieving high sensitivity. This work not only demonstrates an effective doping strategy for improving the performance of lead-free perovskite photodetectors but also highlights their potential as low-toxicity candidates for wearable health monitoring.

Electron-hole injection imbalance caused by slow hole injection is one of the major factors limiting the performance improvement of multinary copper chalcogenide quantum dot light-emitting diodes(QLEDs). This study designed a strategy to modify poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT & ratio;PSS) using a nafion perfluorinated resin(PFI). Taking advantage of the self-assembly property of PFI, a hole injection layer (PFI-PEDOT & ratio;PSS) with a gradient energy level was constructed. Single hole-transporting devices further demonstrate that the PFI-PEDOT & ratio;PSS hole injection layer can effectively reduce the hole injection barrier and enhance hole injection efficiency, thereby improving device performance. Finally, the peak external quantum efficiency of the electroluminescent devices fabricated with PFI-PEDOT & ratio; PSS as the hole injection layer and Cu-In-Zn-S quantum dots as the emitting layer reached 4. 7%, which was 2. 2 times that of the PEDOT & ratio; PSS-based devices. The results indicate that this modification strategy of incorporating PFI into the PEDOT & ratio; PSS hole injection layer can effectively enhance the performance of Cu-In-Zn-S-based QLEDs, and also lays an important research foundation for the subsequent industrial application of environmentally friendly QLEDs.

ABSTRACT With the development of the lighting market, people's reliance on high‐efficiency lighting has grown. Inorganic nanocrystals are highly promising candidates for electroluminescent white light‐emitting diodes (WLEDs) as next‐generation light sources due to their high luminance and high efficiency. This review categorizes recent advances in WLEDs into two categories based on the emitting layer (EML): multi‐component mixed systems and single‐component systems. For multi‐component systems with the advantage of high color rendering indices (CRI), homologous and heterologous nanocrystal mixture with record‐high CRI were summarized. For single‐component systems with the advantage of high efficiency potential, the underlying luminescence mechanisms were compared, including multi‐defect state recombination, intrinsic self‐trapped exciton emission, and doping‐induced white emission, with spectral stability discussion. Notably, this review incorporates cutting‐edge progress, such as II‐VI quantum dot‐based WLEDs (WQLEDs). Finally, key optical and electrical metrics to assess the current state of WQLED development were recapitulated to further identify persistent bottlenecks such as charge injection imbalance and operational stability, and providing forward‐looking perspectives on the transition toward heavy‐metal‐free, industrial‐scale applications.

Ensuring broad-spectrum visible-light absorption and efficient electron extraction is essential for enhancing the efficiency of photocatalytic hydrogen production. To achieve this, manipulating carrier dynamics through cocatalyst heterojunction engineering has attracted considerable concern. However, conventional narrow-bandgap Cu-In-Zn-S (CIZS) nanocrystals (NCs) typically exhibit limited photocatalytic activity due to severe exciton annihilation. Herein, two-dimensional (2D) CIZS nanobelts (NBs) were coupled with Ni9S8 cocatalyst to construct a library of CIZS/Ni9S8 Schottky heterojunctions synthesized via a combined colloidal one-pot and hot-injection strategy. As anticipated, the CIZS/2.0%Ni9S8 heterojunction displayed the optimal photocatalytic hydrogen evolution activity of 2.75 mmol g(-1) h(-1), approximate to 3.31 times higher than that of pristine CIZS NBs (0.83 mmol g(-1) h(-1)). Experimental results uncovered that the enhanced photocatalytic performance originated from the formation of the CIZS/2.0%Ni9S8 Schottky heterojunction, which facilitated efficient charge transfer from CIZS NBs to Ni9S8 and hindered the return of electrons. Moreover, Ni9S8 serves as active catalytic sites, significantly accelerating surface proton reduction reactions. This study provides valuable insights into the rational design and precise synthesis of colloidal multinary Cu-based chalcogenide heterojunctions for efficient photocatalytic energy conversion.

Cadmium-free indium phosphide (InP) quantum dot light-emitting diodes (QLEDs) are promising for next-generation displays, but high-quality green-emitting InP quantum dots (QDs) are still commonly synthesized using highly reactive tris(trimethylsilyl)phosphine. Here, we employ tris(dimethylamino)phosphine as a safer phosphorus precursor to prepare InP/ZnSexS1-x/ZnS QDs. Optimizing the intermediate alloy shell yields green QDs with a photoluminescence quantum yield of 96.1% and a full width at half-maximum of 36.5 nm. A photo-cross-linked PF8Cz:BPO6 hole transport layer improves film compactness and hole transport, while an ultrathin polyvinylpyrrolidone interlayer regulates excessive electron injection. The optimized QLEDs achieve a maximum external quantum efficiency of 10.5% and a peak luminance of 16,219 cd m-2. This work demonstrates a practical strategy for improving the electroluminescent utilization of aminophosphine-derived InP QDs through coordinated material and interface engineering.

Colloidal quantum dots (QDs) are recognized as the key luminescent materials for next-generation display and lighting technologies, owing to their unique size-dependent luminescent properties, high color purity, and high photoluminescent quantum yield (PLQY). Among various QDs, indium phosphide (InP) quantum dots show particular promise for future displays and lighting applications due to their environmentally benign characteristics, broad spectral tunability, and cost-effective solution processability. This article provides a systematic review of recent advances in green-emitting InP QDs, highlighting three critical breakthroughs. First, in the aspect of chemical synthesis, precise regulation of reaction kinetics has enabled the fabrication of green-emitting InP core particles with uniform size and high crystallinity. Second, in terms of surface passivation, both ionic and shell passivation have been implemented to effectively suppress surface defect states in the core, leading to a significant improvement in the PLQY. Third, in terms of ligand engineering, the modification of surface ligands has yielded stable InP QDs with suitably aligned energy levels. Furthermore, the paper presents an outlook on their future development directions.

Simultaneous achievement of green hydrogen production and pollutant removal is an attractive approach for mitigating energy scarcity and environmental pollution. This work successfully constructed an all-solid-state CdZnS/CNT/CuCo2S4 Z-scheme heterojunction via a combined hydrothermal and solvent evaporation approach, enabling highly efficient bifunctional photocatalytic performance in hydrogen production and tetracycline removal. Benefiting from visible light excitation, the tailored CdZnS/CNT/CuCo2S4 heterostructure delivered an outstanding photocatalytic H2 generation activity, as high as 10.29 mmol g- 1 h-1. The catalytic performance was 3.3 times superior to pristine CdZnS. Moreover, it achieved 92.3% degradation of tetracycline within 30 min. The boosted photocatalytic performance originates from the Z-type charge transmission pathway supported by CNT electron bridges, significantly promoting carrier separation and transport. Excited electrons in CdZnS reduce water to produce hydrogen, while the holes in CuCo2S4 degrade tetracycline. This study paves a rational pathway for the fabrication of Z-scheme heterojunction photocatalysts that employ carbon nanotubes as electron mediators.

Metal halide perovskite light-emitting diodes (PeLEDs) have demonstrated excellent external quantum efficiency (EQE), easy colour tunability and low-cost processability, making them promising next-generation display techniques1-3. However, PeLEDs still underperform compared with organic light-emitting diodes (LEDs) with an EQE of about 40% because of insufficient charge confinement and defect-caused non-radiative recombination on the film surface. Here we report a spontaneously formed 3D/2D vertically oriented perovskite heterojunction by means of a simple one-step spin-coating method, which could effectively confine the charge carriers and shift the radiation zone away from the defect-rich surface region. Notably, the 2D perovskite on top exhibits a wrinkled surface morphology, which offers up to 45.4% light extraction efficiency. The resulting PeLEDs achieved an EQE of 42.9% for the green emission (certified 42.3%). Our work sheds light on the strategies for fabricating high-efficiency PeLEDs in the future.

ABSTRACT Perovskite photodetectors face a challenge in balancing high photocurrent and low dark current for practical self‐powered applications. Conventional hole‐transport layer poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) suffers from instability and inadequate electron‐blocking capability. Herein, we report a solution‐processable Sn(II)‐doped phosphomolybdic acid (PMA:Sn) as a multifunctional hole‐transport/electron‐blocking layer for p–i–n type methylammonium lead iodide (MAPbI 3 ) photodetectors. The incorporation of Sn(II) optimizes the redox characteristics of the Keggin‐type PMA, enhancing the hole conductivity and adjusting its highest occupied molecular orbitals (HOMO) level for improved energy alignment with the perovskite, while simultaneously elevating its lowest unoccupied molecular orbital (LUMO) level to effectively block electron leakage from the perovskite. The resulting photodetectors achieve an ultralow dark current density of 2.13 × 10 −9 A·cm −2 and a photocurrent density of 9.53 × 10 −3 A·cm −2 at 0 V bias, yielding a record on/off ratio of 4.47 × 10 6 . The specific detectivity exceeds 10 12 Jones across 320–785 nm, with a linear dynamic range of 130 dB. The performance is attributed to the synergistic effect of high hole conductivity, optimal energy alignment, and efficient charge extraction, as validated by transient measurements. This work demonstrates the potential of redox‐tailored polyoxometalates as stable and superior alternatives to organic transport layers in next‐generation optoelectronics.

Indium phosphide-based quantum dots (InP-based QDs) have emerged as promising candidates for nextgeneration display and optoelectronic technologies, offering exceptional photoluminescent (PL) properties including high efficiency, narrow emission spectra, and precisely tunable wavelengths. Nevertheless, their widespread commercialization encounters substantial obstacles, primarily stemming from persistent challenges in synthetic control and material processing. Critical performance parameters-including photoluminescence quantum yield (PL QY, currently<90% for most systems), emission linewidth (typically>35 nm) as well as external quantum efficiency (EQE) and operational stability of device-continue to show only incremental improvements, highlighting the urgent need for fundamental breakthroughs in QDs synthesis, surface engineering and device optimization. This review systematically examines the nucleation mechanisms governing InP core formation and outlines key strategies for optimizing InP-based core/shell QDs. Furthermore, we present a comprehensive analysis of recent breakthroughs in red, green, and blue-emitting InP-based QD light-emitting diodes (QLEDs) development, focusing on modulation of charge transport engineering and suppression of charge leakage. Finally, we critically evaluate the remaining commercialization challenges and future prospects for InP-based QLEDs in next-generation display and optoelectronic technologies, outlining potential pathways for overcoming current limitations.

Two-dimensional (2D) Dion-Jacobson (DJ)-phase tin-based perovskites show great promise for field-effect transistors (FETs) due to their excellent charge transport properties and structural stability. However, the limited variety of diammonium cations has hindered their further development in electronic devices. In this work, we synthesized a 2D DJ-phase tin perovskite, 3AMPYSnI4, using asymmetric diammonium cation 3-(aminomethyl)pyridinium (3AMPY2+). Single-crystal analysis confirms a typical DJ-phase structure with zigzag-stacked inorganic layers. The 3AMPYSnI4 thin film is polycrystalline without a preferred orientation, exhibiting a high absorption coefficient (∼105 cm-1) and p-type nature. The 3AMPYSnI4 FETs show typical p-type transport behavior with a maximum hole mobility of 3.12 × 10-3 cm2 V-1 s-1 and demonstrate good operational stability. Moreover, under 460 nm illumination, the device achieves a responsivity of 1.20 × 102 A/W and a specific detectivity of 1.46 × 1012 Jones, highlighting its potential for visible-light detection. This study provides a new direction for developing 2D DJ-phase perovskites and their applications in high-performance optoelectronic devices.

Quantum dot light-emitting diodes(QLEDs), owing to their high color purity, excellent emission efficiency, solution processability, full-color tunability, and compatibility with existing fabrication techniques, are regarded as strong candidates for next-generation high-resolution and low-power display devices. The realization of quantum dot patterning is a prerequisite for their display applications, giving rise to the emergence of various photolithographic techniques. At present, QLED patterning technologies are evolving from methods such as traditional photolithography and inkjet printing, which involve complex processes and often induce performance degradation, toward direct photolithography approaches that enable high resolution and nondestructive patterning. This article reviews the fundamental principles of direct photolithography of quantum dots, with a particular focus on the crosslinking mechanisms, lithographic performance, and impacts on QLED device characteristics of three representative photosensitive groups (azide, azo, and disulfide). Furthermore, the future development trends of direct photolithography for quantum dots and its potential directions in QLED displays are discussed, providing valuable insights for the advancement of patterned QLED display technologies.

The device performance of Cu-In-Zn-S (CIZS)-based quantum-dot light-emitting diodes (QLEDs) still lags far behind CdSe-based QLEDs, which mainly arise from unique trap-related recombination in the CIZS quantum dots (QDs). Herein, the carrier dynamics behavior of CIZS-based and CdSe-based QLEDs was studied by transient electroluminescence (TrEL) technology, and the difference in the falling edge of the TrEL response was obviously observed in both QLEDs. The results show that Cu-related defect states (Cu-states) created a substantial hole injection barrier, making traditional hole-transport layer modifications ineffective for carrier injection and transport balance. By engineering the ZnO electron transport layer (ETL), the electron injection and transport were reduced, which suppressed trap-state-mediated non-radiative recombination. At last, carrier dynamics models were proposed to clarify the phenomenon of falling edge overshoot in the CIZS-based QLEDs. This approach overcomes the intrinsic hole transport limitation in CIZS QDs caused by Cu-states, offering a viable method to balance the carrier injection and transport without enhancing hole injection.

I-III-VI group semiconductor nanocrystals (NCs) with narrow-bandwidth emission have emerged as promising candidates for display technologies due to their tunable emission wavelength and eco-friendly composition. Herein, Ga-rich Ag-In-Ga-S (AIGS) NCs exhibited a narrow photoluminescence emission with a full width at half maximum (fwhm) of 29 nm, which was derived from In-rich Ag-In-Ga-S NCs with an fwhm of 113 nm via a cation exchange strategy. The evolution process was studied systematically using steady- and transient-state spectroscopic techniques, revealing that the narrow photoluminescence (PL) bandwidth primarily originated from free-to-bound radiative recombination. The result was consistent with first-principles calculations. Furthermore, the electroluminescent devices based on AIGS NCs showed a record narrow electroluminescent bandwidth of less than 30 nm, and the maximum external quantum efficiency (EQE) could reach up to 1.2%.

Miniaturized optical wavelength-sensing devices based on solution-processed organic materials hold great promise for integration into portable and wearable technologies. Yet, the realization of self-powered compact wavelength sensors remains elusive. Here, we report a self-powered wavelength sensor built from broadband photodetectors featuring a meticulously engineered PM6:L8-BO active layer. By systematically varying the donor-acceptor stoichiometries and implementing these blends in nano-scale active layers (50 and 100 nm) that modulate the internal optical field distribution, we tailor the spectral responsivity of individual sensor units, yielding distinct wavelength-dependent optoelectronic signatures. An array of these wavelength-discriminating units enables quantitative discrimination and identification of incident light wavelengths. The device accurately resolves wavelengths from 380 to 850 nm with a resolution better than similar to 1 nm, determined through the photocurrent ratio mapping of the four photodetector elements. As a proof of concept, we demonstrate the device's capability in wavelength recognition and full-color imaging, underscoring its potential for compact, self-powered, and versatile optical sensing platforms.

Ensuring broad‐spectrum visible‐light absorption and efficient electron extraction is essential for enhancing the efficiency of photocatalytic hydrogen production. To achieve this, manipulating carrier dynamics through cocatalyst heterojunction engineering has attracted considerable concern. However, conventional narrow‐bandgap Cu–In–Zn–S (CIZS) nanocrystals (NCs) typically exhibit limited photocatalytic activity due to severe exciton annihilation. Herein, two‐dimensional (2D) CIZS nanobelts (NBs) were coupled with Ni 9 S 8 cocatalyst to construct a library of CIZS/Ni 9 S 8 Schottky heterojunctions synthesized via a combined colloidal one‐pot and hot‐injection strategy. As anticipated, the CIZS/2.0%Ni 9 S 8 heterojunction displayed the optimal photocatalytic hydrogen evolution activity of 2.75 mmol g −1 h −1 , ≈3.31 times higher than that of pristine CIZS NBs (0.83 mmol g −1 h −1 ). Experimental results uncovered that the enhanced photocatalytic performance originated from the formation of the CIZS/2.0%Ni 9 S 8 Schottky heterojunction, which facilitated efficient charge transfer from CIZS NBs to Ni 9 S 8 and hindered the return of electrons. Moreover, Ni 9 S 8 serves as active catalytic sites, significantly accelerating surface proton reduction reactions. This study provides valuable insights into the rational design and precise synthesis of colloidal multinary Cu‐based chalcogenide heterojunctions for efficient photocatalytic energy conversion.

The advancement of environmentally benign I-III-VI colloidal quantum dots (QDs) has established a promising materials platform to replace cadmium-based counterparts. However, in practical device architectures, especially blue-emitting devices, abundant surface nonradiative recombination centers and imbalanced carrier injection often lead to suboptimal device performance, thereby hindering their deployment in display technologies. Herein, we employ a zinc iodide (ZnI2) post-treatment for the Cu-Ga-Zn-S (CGZS) QDs film strategy, effectively passivating surface defects and nonradiative sites, thereby enhancing device performance. The treated QDs facilitate the formation of an interface dipole, which effectively elevates the overall energy levels of the QDs while simultaneously reducing the hole injection barrier, leading to an enhanced hole injection efficiency. Working in concert, these effects facilitate balanced carrier injection and optimize exciton recombination, thereby boosting the device efficiency and operational stability. Consequently, the peak external quantum efficiency (EQE) exhibits a favorable improvement, increasing from 1.01% in the pristine device to 1.90% after treatment. This work offers an effective approach to achieving balanced carrier injection in quantum-dot light-emitting diodes (QLEDs) and establishes a solid foundation for the development of high-performance, cadmium-free, blue-emitting QLEDs.

In current white-light-emitting diodes (WLEDs), broadband emission is typically achieved by mixing multiple luminescent components. However, challenges such as interfacial incompatibility and energy-level misalignment significantly limit device performance and industrial scalability. To address these limitations of issues, this study proposes an Mn2+-doped Cs3Cu2I5 lead-free perovskite for luminescence regulation and successfully constructs a single-component WLED. Through a grinding-calcination process, Mn2+ is doped into the Cs3Cu2I5 lattice, introducing additional energy levels and activating d-d transitions. This enables an energy-level-dominated transformation from single-band blue emission to dual-band blue-yellow emission. Based on this strategy, we fabricated a series of color-tunable LED devices. Among them, the optimized WLED exhibits Commission Internationale de l'Éclairage chromaticity coordinates of (0.28, 0.33) and a color rendering index of 64.2, demonstrating excellent operational stability. This work challenges the conventional perception that white-light emission requires multi-component synergy and offers a novel design strategy for future lead-free perovskite-based WLEDs. It also opens up new ways, to the best of our knowledge, for the development of environmentally friendly and energy-efficient lighting appliances.