Engineering the Exciton Dissociation in Quantum‐Confined 2D CsPbBr3 Nanosheet Films

Recent years have witnessed a rapid development of all‐inorganic halide perovskite in optoelectronic devices. Ultrathin 2D CsPbBr₃ nanosheets (NSs) with large lateral dimensions have demonstrated exceptional photophysical properties because of their analogous exciton electronic structure to quantum wells. Despite the incredible progress on device performance, the photophysics and carrier transportation parameters of quantum‐confined CsPbBr₃ NSs are lacking, and the fundamental understanding of the exciton dissociation mechanism is far less developed. Here, a ligands rearrangement mechanism is proposed to explain why annealed NS films have an increased charge transfer rate and a decreased exciton binding energy and lifetime, prompting tunneling as a dominant way of exciton dissociation to separate photogenerated excitons between neighboring NSs. This facile but efficient method provides a new insight to manipulate perovskite nanocrystals coupling. Moreover, ultrathin 2D CsPbBr₃ NS film is demonstrated to have a enhanced absorption cross section and high carrier mobility of 77.9 cm² V^?1 s^?1, contributing to its high responsivity of 0.53 A W^?1. The photodetector has a long‐term stability up to three months, which are responsible for reliable perovskite‐based device performance.     

Photon‐Induced Reversible Phase Transition in CsPbBr3 Perovskite

Structure reorganization within perovskite materials has attracted much attention due to its assisted appealing features in optoelectronic devices, such as achieving continue‐wave laser and performance enhancement in photovoltaic devices. Unfortunately, the difficulty of controlling reorganization processing and unclear underlying mechanisms impose an impediment for taking advantage of the structural reorganization in pursuit of distinctive functions in perovskite‐based devices. In this work, using above‐bandgap illumination with a small energy threshold (1.6 mW cm^?2) triggering phase transition from orthorhombic to tetragonal in CsPbBr₃ is first reported. This photon‐induced structure reorganization is reversible and presents a fast and controllable response (<0.5 s) to light on/off. Raman spectroscopy and density functional theory calculations reveal that such a dynamic structure reorganization is caused by the transition of torsion direction in Pb–Br octahedral, while the diffusion potential difference induced local Coulombic field is proved to drive this process. The findings provide a deep understanding for universal structure reorganization under irradiation in perovskite materials and encourage further study of the novel functions associated with structure reorganization inducing temporal behaviors in optoelectronic devices, for example variations in dielectric constant and band edge fluctuation induced Rashba effects, which show a significant influence on perovskite‐based optoelectronic devices.     

All-Inorganic CsPbBr3 Perovskite Nanocrystals/2D Non-Layered Cadmium Sulfide Selenide for High-Performance Photodetectors by Energy Band Alignment Engineering

Perovskites have attracted intensive attention as promising materials for the application in various optoelectronic devices due to their large light absorption coefficient, high carrier mobility, and long charge carrier diffusion length. However, the performance of the pure perovskite nanocrystals-based device is extremely restricted by the limited charge transport capability due to the existence of a large number of the grain boundary between perovskite nanocrystals. To address these issues, a high-performance photodetector based on all-inorganic CsPbBr₃ perovskite nanocrystals/2D non-layered cadmium sulfide selenide heterostructure has been demonstrated through energy band engineering with designed typed-II heterostructure. The photodetector exhibits an ultra-high light-to-dark current ratio of 1.36 × 10⁵, a high responsivity of 2.89 × 10² A W⁻¹, a large detectivity of 1.28 × 10¹⁴ Jones, and the response/recovery time of 0.53s/0.62 s. The enhancement of the optoelectronic performance of the heterostructure photodetector is mainly attributed to the efficient charge carrier transfer ability between the all-inorganic CsPbBr₃ perovskites and 2D cadmium sulfide selenide resulting from energy band alignment engineering. The charge carriers’ transfer dynamics and the mechanism of the CsPbBr₃ perovskites/2D non-layered nanosheets interfaces have also been studied by state-state PL spectra, fluorescence lifetime imaging microscopy, time-resolved photoluminescence spectroscopy, and Kelvin probe force microscopy measurements.     

Improved Performance and Stability of All‐Inorganic Perovskite Light‐Emitting Diodes by Antisolvent Vapor Treatment

All‐inorganic perovskite light‐emitting diodes (LEDs) reveal efficient luminescence with high color purity, but their modest brightness and poor stability are still critical drawbacks. Here, the luminescent efficiency and the stability of perovskite LEDs (PeLEDs) are boosted by antisolvent vapor treatment of CsPbBr₃ embedded in a dielectric polymer matrix of polyethylene oxide (PEO). A unique method is developed to obtain high quality CsPbBr₃ emitting layers with low defects by controlling their grain sizes. CsPbBr₃ in PEO matrix is post‐treated with antisolvent of chloroform (CF), leading to microcrystals with a size of ≈5 µm along the in‐plane direction with active emitting composite of 90%. A device based on CF post‐treatment (CsPbBr₃‐PEO‐CF) film displays a brightness of up to 51890 cd m^?2 with an external quantum efficiency of 4.76%. CsPbBr₃‐PEO‐CF PeLED still maintains 82% of its initial efficiency after 80 h continuous operation in ambient air, which indicates relatively good device stability. This work highlights that film quality is not only key to promoting fluorescence in CsPbBr₃, but also to achieving higher performance PeLEDs.     

Inch‐Size Single Crystal of a Lead‐Free Organic–Inorganic Hybrid Perovskite for High‐Performance Photodetector

Large‐size crystals of organic–inorganic hybrid perovskites (e.g., CH₃NH₃PbX₃, X = Cl, Br, I) have gained wide attention since their spectacular progress on optoelectronic technologies. Although presenting brilliant semiconducting properties, a serious concern of the toxicity in these lead‐based hybrids has become a stumbling block that limits their wide‐scale applications. Exploring lead‐free hybrid perovskite is thus highly urgent for high‐performance optoelectronic devices. Here, a new lead‐free perovskite hybrid (TMHD)BiBr₅ (TMHD = N,N,N,N‐tetramethyl‐1,6‐hexanediammonium) is prepared from facile solution process. Emphatically, inch‐size high‐quality single crystals are successfully grown, the dimensions of which reach up to 32 × 24 × 12 mm³. Furthermore, the planar arrays of photodetectors based on bulk lead‐free (TMHD)BiBr₅ single crystals are first fabricated, which shows sizeable on/off current ratios (≈10³) and rapid response speed (τ_rise = 8.9 ms and τ_decay = 10.2 ms). The prominent device performance of (TMHD)BiBr₅ strongly underscores the lead‐free hybrid perovskite single crystals as promising material candidates for optoelectronic applications.     

Surface Defect Suppression for High Color Purity Light-Emitting Diode of Free-Standing Single-Crystal Perovskite Film

High color purity is one of the important features for single-crystal metal halide perovskite light-emitting diode (LED). Despite single-crystal perovskite showing low bulk defect concentration, single-crystal perovskite LEDs do not exhibit high color purity advantage due to the absence of effective surface defect passivation. Herein, one fully wrapped structure is proposed to passivate the surface of the free-standing CsPbBr₃ single-crystal films. The surface of CsPbBr₃ single-crystal films is wrapped by ultra-thin polymethyl methacrylate, precisely controlling the thickness. The single-crystal perovskite film device can achieve high color purity with a full width at half maximum (FWHM) of 15.8 nm) and a large luminescent area of 2.25 mm². It is observed that surface passivation is due to interaction of CO bond in polymer chains with the Lewis acid PbBr₂. The passivated perovskite single-crystal films significantly improve carrier lifetime and suppress surface defects. It is noteworthy that the passivated free-standing single-crystal perovskite films are feasible to build up a vertical LED device structure, avoiding the edge glowing and short-circuiting of the LED device. This study demonstrates the large luminescent area of the high-quality millimetre-scale free-standing single-crystal films for wide color gamut display and vertical optoelectronic devices.     

Enhanced On–Off Ratio Photodetectors Based on Lead‐Free Cs3Bi2I9 Single Crystal Thin Films

Hybrid organic–inorganic lead halide perovskite single crystal thin film (SCTF) recently has attracted enormous interest in the field of optoelectronic devices, since it efficiently resolves the trade‐off between thickness and carrier diffusion length. However, the toxicity of lead element and the instability induced by organic component still hinder its future developments. In this work, lead‐free all‐inorganic Cs₃Bi₂I₉ SCTF with a high orientation along (00h) has been in situ grown on indium tin oxide (ITO) glass via a space‐limited solvent evaporation crystallization method. The trap density of Cs₃Bi₂I₉ SCTF (5.7 × 10¹² cm^?3) is 263 folds lower than that of the polycrystalline thin film (PCTF) counterpart, together with a 5‐order‐of‐magnitude higher carrier mobility. These superior charge transfer properties enable a photoresponse on–off ratio as high as 11 000, which far surpasses that of the PCTF device by 460 folds, comparable to the lead halide perovskite. Furthermore, the Cs₃Bi₂I₉ SCTF photodetector exhibits outstanding stability even without any encapsulation, whose initial performance is well maintained after aging 1000 h in humid air of 50% RH or continuous on–off light illumination for 20 h. This work will pave the way to produce new families of high‐performance, stable, and nontoxic perovskite SCTF for future optoelectronic applications.     

Enhancing Resistive Switching Performance and Ambient Stability of Hybrid Perovskite Single Crystals via Embedding Colloidal Quantum Dots

Hybrid organic‐inorganic halide perovskites are actively pursued for optoelectronic technologies, but the poor stability is the Achilles’ heel of these materials that hinders their applications. Very recently, it has been shown that lead sulfide (PbS) quantum dots (QDs) can form epitaxial interfaces with the perovskite matrix and enhance the overall stability. In this work, it is demonstrated that embedding QDs can significantly modify the transport property of pristine perovskite single crystals, endowing them with new functionalities besides being structurally robust and free from grain boundaries. Resistive switching memory devices are constructed using solution‐processed CH₃NH₃PbBr₃ (MAPbBr₃) perovskite single crystals and the QD‐embedded counterparts. It is found that QDs could significantly enhance the charge transport and reduce the current–voltage hysteresis. The pristine singe crystal device exhibits negative differential resistance, while the QD‐embedded crystals are featured with filament‐type switching behavior and much improved device stability. This study underscores the potential of QD‐embedded hybrid perovskites as a new media for advanced electronic devices.     

Epitaxial Growth of 2D Bi2O2Se Nanoplates/1D CsPbBr3 Nanowires Mixed-Dimensional Heterostructures with Enhanced Optoelectronic Properties

The 2D/1D mixed-dimensional van der Waals heterostructures have great potential for electronics and optoelectronics with high performance and multifunctionality. The epitaxy of 1D micro/nanowires on 2D layered materials may efficiently realize the large-scale preparation of 2D/1D heterostructures, which is critically important for their practical applications. So far, however, only the wires of Bi₂S₃, Te, and Sb₂Se₃ have been epitaxially grown on MoS₂ or WS₂. Here, it is reported that the epitaxial growth of 1D CsPbBr₃ nanowires on 2D Bi₂O₂Se nanoplates through a facile vertical vapor deposition method. The CsPbBr₃ wires are well aligned on the Bi₂O₂Se plates in fourfold symmetry with the epitaxial relationships of [001]_CsPbBr3||[200]_Bi2O2Se and [1-10]_CsPbBr3||[020]_Bi2O2Se. The photoluminescence results reveal that the emission from CsPbBr₃ is significantly quenched in the heterostructure, which implies the charge carriers transfer from CsPbBr₃ to Bi₂O₂Se. The waveguide characterization shows that the epitaxial CsPbBr₃ wires may efficiently confine and guide their emission, which favors the light absorption of Bi₂O₂Se. Importantly, the photocurrent mapping and spectra of the devices based on these 2D/1D heterostructures prove that the epitaxial CsPbBr₃ wires remarkably enhances the photoresponse of Bi₂O₂Se, which indicates these heterostructures can be applied in high-performance optoelectronic devices or on-chip integrated photonic circuits.     

Full coverage all-inorganic cesium lead halide perovskite film for high-efficiency light-emitting diodes assisted by 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene

A full coverage all-inorganic cesium lead halide perovskite CsPbBr₃ film is achieved by introducing a small organic molecule material, 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB), as a solution additive. The light-emitting diode (LED) using this CsPbBr₃:TmPyPB perovskite film as light emitting layer exhibit improved electroluminescent (EL) performance with the maximum brightness of 22309 cd/m², highest current efficiency of 8.77 cd/A, and external quantum efficiency (EQE) of 2.27%, which are 8.6, 10.2 and 10.3 times to that of neat CsPbBr₃ film based LED, respectively. The enhanced EL performances are ascribed to less current leakage due to full coverage, and improved electron transporting in the CsPbBr₃:TmPyPB perovskite film.     

Highly Controlled Zigzag Perovskite Nanocrystals Enabled by Dipole-Induced Self-Assembly of Nanocubes for Low-Threshold Amplified Spontaneous Emission and Lasing

Self-assembly of nanocrystals into controlled structures while uncompromising their properties is one of the key steps in optoelectronic device fabrication. Herein, zigzag CsPbBr₃ perovskite nanocrystals are demonstrated with a precise number of components with nanocube morphology, these can be successfully obtained through a dipole-induced self-assembly process. The addition of a trace amount of deionized water facilitates the transfer from CsPbBr₃ nanocubes to intermediates of CsPb₂Br₅ and Cs₃In₂Br₉, which then fastly release reaction monomers leading to further homogenous nucleation of CsPbBr₃ nanocubes, followed by the formation of zigzag CsPbBr₃ nanocrystals through a dipole-induced self-assembly process. Dipole moment along <110> axis is found to be the driving force for the assembly of nanocubes into zigzag nanocrystals. The zigzag CsPbBr₃ nanocrystals exhibit desirable optical properties comparable to their nanocube counterparts and offer advantages for amplified spontaneous emission and lasing applications with low pump thresholds of 3.1 and 6.02 µJ cm⁻², respectively. This study not only develops a strategy for producing highly controlled zigzag perovskite nanocrystals and provides insights on the dipole-induced self-assembly mechanisms, but also opens an avenue for their application in lasing.     

Low Fatigue in Epitaxial Pb(Zr<Subscript>0.2</Subscript>Ti<Subscript>0.8</Subscript>)O<Subscript>3</Subscript> on Si Substrates with LaNiO<Subscript>3</Subscript> Electrodes by RF Sputtering

Epitaxial PZT (001) thin films with a LaNiO₃ bottom electrode were deposited by radio-frequency (RF) sputtering onto Si(001) single-crystal substrates with SrTiO₃/TiN buffer layers. Pb(Zr_0.2Ti_0.8)O₃ (PZT) samples were shown to consist of a single perovskite phase and to have an (001) orientation. The orientation relationship was determined to be PZT(001)[110]∥LaNiO₃(001)[110]∥SrTiO₃ (001)[110]∥TiN(001)[110]∥Si(001)[110]. Atomic force microscope (AFM) measurements showed the PZT films to have smooth surfaces with a roughness of 1.15 nm. The microstructure of the multilayer was studied using transmission electron microscopy (TEM). Electrical measurements were conducted using both Pt and LaNiO₃ as top electrodes. The measured remanent polarization P _r and coercive field E _c of the PZT thin film with Pt top electrodes were 23 μC/cm² and 75 kV/cm, and were 25 μC/cm² and 60 kV/cm for the PZT film with LaNiO₃ top electrodes. No obvious fatigue after 10¹⁰ switching cycles indicated good electrical endurance of the PZT films using LaNiO₃ electrodes, compared with the PZT film with Pt top electrodes showing a significant polarization loss after 10⁸ cycles. These PZT films with LaNiO₃ electrodes could be potential recording media for probe-based high-density data storage.     

Epitaxial growth of CsPbBr3/PbS single-crystal film heterostructures for photodetection

Epitaxial high-crystallization film semiconductor heterostructures has been proved to be an effective method to pre-pare single-crystal films for different functional devices in modern microelectronics,electro-optics,and optoelectronics.With su-perior semiconducting properties,halide perovskite materials are rising as building blocks for heterostructures.Here,the con-formal vapor phase epitaxy of CsPbBr3 on PbS single-crystal films is realized to form the CsPbBr3/PbS heterostructures via a two-step vapor deposition process.The structural characterization reveals that PbS substrates and the epilayer CsPbBr3 have clear relationships:CsPbBr3(110)//PbS(100),CsPbBr3[110]//PbS[001]and CsPbBr3[001]//PbS[010].The absorption and photolu-minescence(PL)characteristics of CsPbBr3/PbS heterostructures show the broadband light absorption and efficient photogener-ated carrier transfer.Photodetectors based on the heterostructures show superior photoresponsivity of 15 A/W,high detectiv-ity of 2.65×1011 Jones,fast response speed of 96 ms and obvious rectification behavior.Our study offers a convenient meth-od for establishing the high-quality CsPbBr3/PbS single-crystal film heterostructures and providing an effective way for their ap-plication in optoelectronic devices.     

Healing All‐Inorganic Perovskite Films via Recyclable Dissolution–Recyrstallization for Compact and Smooth Carrier Channels of Optoelectronic Devices with High Stability

The strong ionic character endows all‐inorganic CsPbX₃ (X = Cl, Br, I) perovskite nanocrystals (NCs) with different chemical features from classical Cd‐based NCs, especially when considering their interaction with polar solvents and surfactants. This has aroused intensive interest, but is still short of comprehensive understanding. More significantly, above characteristic may be used to improve the quality of perovskite thin films, which is crucial for the carrier transport inside optoelectronic devices. Here, an interesting recyclable dissolution–recyrstallization phenomenon of all‐inorganic pervoskite, as well as its application on room temperature (RT) self‐healing of compact and smooth carrier channels in ambient atmosphere for high‐performance PDs with high stability is reported. First, according to solubility equilibrium principle, the size of CsPbBr₃ crystals can be reversibly tuned in the range of 10 nm–1 μm through washing with polar solvent or stirring with assistance of surfactants at RT. Second, such phenomenon is applied for significant film quality improvement by forming a liquid circumstance within films, which can transport matter at surface and sharp parts into the gaps, healing themselves at RT. This strategy results in large‐area, crack‐free, low‐roughness perovskite thin films. Obviously, such improvement facilitates transport and extraction of carriers in the channels of devices, which has been evidenced by the improvement of performances of the corresponding PDs at ambient condition.     

Enhanced Performance of Planar Perovskite Solar Cells Induced by Van Der Waals Epitaxial Growth of Mixed Perovskite Films on WS2 Flakes

Organic–inorganic metal halide perovskite solar cells (PSCs) have attracted much research interest owing to their high power conversion efficiency (PCE), solution processability, and the great potential for commercialization. However, the device performance is closely related to the quality of the perovskite film and the interface properties, which cannot be easily controlled by solution processes. Here, 2D WS₂ flakes with defect‐free surfaces are introduced as a template for van der Waals epitaxial growth of mixed perovskite films by solution process for the first time. The mixed perovskite films demonstrate a preferable growth along (001) direction on WS₂ surfaces. In addition, the WS₂/perovskite heterojunction forms a cascade energy alignment for efficient charge extraction and reduced interfacial recombination. The inverted PSCs with WS₂ interlayers show high PCEs up to 21.1%, which is among the highest efficiency of inverted planar PSCs. This work demonstrates that high‐mobility 2D materials can find important applications in PSCs as well as other perovskite‐based optoelectronic devices.     

Photoelectrochemically Active and Environmentally Stable CsPbBr3/TiO2 Core/Shell Nanocrystals

Inherent poor stability of perovskite nanocrystals (NCs) is the main impediment preventing broad applications of the materials. Here, TiO₂ shell coated CsPbBr₃ core/shell NCs are synthesized through the encapsulation of colloidal CsPbBr₃ NCs with titanium precursor, followed by calcination at 300 °C. The nearly monodispersed CsPbBr₃/TiO₂ core/shell NCs show excellent water stability for at least three months with the size, structure, morphology, and optical properties remaining identical, which represent the most water‐stable inorganic shell passivated perovskite NCs reported to date. In addition, TiO₂ shell coating can effectively suppress anion exchange and photodegradation, therefore dramatically improving the chemical stability and photostability of the core CsPbBr₃ NCs. More importantly, photoluminescence and (photo)electrochemical characterizations exhibit increased charge separation efficiency due to the electrical conductivity of the TiO₂ shell, hence leading to an improved photoelectric activity in water. This study opens new possibilities for optoelectronic and photocatalytic applications of perovskites‐based NCs in aqueous phase.     

Optoelectronic Coincidence Detection with Two-Dimensional Bi2O2Se Ferroelectric Field-Effect Transistors

Information processing with optoelectronic devices provides an alternative way to efficiently process hybrid optical and electronic signals. Ferroelectric field-effect transistors (FeFETs) can effectively respond to external optical and electrical stimuli by modulating their polarization states. Here, a 2D FeFET is demonstrated by the epitaxial growth of high-quality 2D bismuth layered oxyselenide (Bi₂O₂Se) films on PMN-PT(001) ferroelectric single-crystal substrates. Upon switching the polarization direction of PMN-PT, the authors realize in situ, reversible, and nonvolatile manipulation of the resistance of Bi₂O₂Se thin film ( ≈ 877%). The device simultaneously exhibits a polarization-dependent photoresponse through visible light (λ  =  405 nm) and infrared light (IR, λ  =  980 nm) illumination. Combining optical stimuli with ferroelectric gating, it is demonstrated that the devices not only show nonvolatile memory and optoelectronic responses, but also show coincidence detection of visible and IR light. This work holds great potential in constructing new multiresponse and multifunction 2D-FeFETs.     

Self-Assembled Perovskite Nanoislands on CH3NH3PbI3 Cuboid Single Crystals by Energetic Surface Engineering

Organometal perovskite single crystals have been recognized as a promising platform for high-performance optoelectronic devices, featuring high crystallinity and stability. However, a high trap density and structural nonuniformity at the surface have been major barriers to the progress of single crystal-based optoelectronic devices. Here, the formation of a unique nanoisland structure is reported at the surface of the facet-controlled cuboid MAPbI₃ (MA = CH₃NH₃⁺) single crystals through a cation interdiffusion process enabled by energetically vaporized CsI. The interdiffusion of mobile ions between the bulk and the surface is triggered by thermally activated CsI vapor, which reconstructs the surface that is rich in MA and CsI with reduced dangling bonds. Simultaneously, an array of Cs-Pb-rich nanoislands is constructed on the surface of the MAPbI₃ single crystals. This newly reconstructed nanoisland surface enhances the light absorbance over 50% and increases the charge carrier mobility from 56 to 93 cm² V⁻¹ s⁻¹. As confirmed by Kelvin probe force microscopy, the nanoislands form a gradient band bending that prevents recombination of excess carriers, and thus, enhances lateral carrier transport properties. This unique engineering of the single crystal surface provides a pathway towards developing high-quality perovskite single-crystal surface for optoelectronic applications.     

3D/2D Perovskite Single Crystals Heterojunction for Suppressed Ions Migration in Hard X-Ray Detection

Halide perovskites exhibit diverse properties depending on their compositions. However, integrating desired properties into one material is still challenging. Here, a facile solution-processed epitaxial growth method to grow 2D perovskite single crystal on top of 3D perovskite single crystal, which can passivate the surface defects for improved device performance is reported. Short formamidine (FA⁺) ions are replaced by long organic cations, which can fully align and cover the single crystal surface to prevent the ions migration or short FA⁺ ions volatilization. The thickness of epitaxial layer can be finely adjusted by controlling the growth time. The defect density of single crystals heterojunction is only 3.18 × 10⁹ cm⁻³, and the carrier mobility is 80.43 cm² V⁻¹ s⁻¹, which is greater than that of the control 3D perovskite single crystal. This study for the first time realized large area 3D/2D perovskite single crystals heterojunction, which suppressed ions migration and exhibited advanced performance in hard X-rays detection applications. This strategy also provides a way to grow large area 2D perovskite single crystal from solution processes.     

Facile method for the preparation of high-performance photodetectors with a GQDs/perovskite bilayer heterostructure

A high-performance nitrogen doped graphene quantum dots (GQDs)/all-inorganic (CsPbBr₃) perovskite nanocrystals (NCs) heterostructure photodetector was fabricated on a quartz substrate, using the low cost spin coating technique followed by hot plate annealing. The GQDs/CsPbBr₃ NCs heterostructure photodetector exhibits a high overall performance with a photoresponsivity of 0.24 AW⁻¹, on/off ratio of 7.2 × 10⁴, and specific detectivity of up to 2.5 × 10¹² Jones. The on/off ratio of the hybrid device was improved by almost ten orders of magnitude, and the photoresponsivity was enhanced almost three times compared to the single layer perovskite NCs photodetector. The performance enhancement of the hybrid device was due to its highly efficient carrier separation at the GQDs/CsPbBr₃ NCs interface. This results from the coupling of the GQDs layer, which efficiently extracts and transports the photogenerated carriers, with the CsPbBr₃ NCs layer, which has a large absorption coefficient and high quantum efficiency. The interfacial charge transfer from the CsPbBr₃ NCs to the GQDs layer was demonstrated by the quenching in the photoluminescence (PL) spectra, and the fast-average decay time in the time-resolved photoluminescence (Trpl) spectra of the hybrid photodetector. Moreover, the performance-enhancement mechanism of the hybrid GQDs/CsPbBr₃ photodetector was elucidated by analyzing the band alignment of the GQDs and CsPbBr₃ under laser illumination.