Vertical-type 3D/Quasi-2D n-p Heterojunction Perovskite Photodetector

This research demonstrates a state-of-the-art vertical-transport photodetector with an n-type 3D MAPbI₃/p-type quasi-2D (Q-2D) BA₂MA₂Pb₃I₁₀ perovskite heterojunction. This structure introduces a ≈0.6 V built-in electric field at the n-p junction that greatly improves the characteristics of the perovskite photodetector, and the presence of Q-2D perovskite on the surface improves the life. The electrical polarities of the 3D and the Q-2D perovskite layers are simply controlled by self-constituent doping, making clearly defined n-p characteristics. Doctor-blade coating is used to fabricate the photodetector with a large area. The Q-2D materials with highly oriented (040) Q-2D (n = 2,3) planes are near the surface, and the (111) preferred planes mixed with high index Q-2D materials (n = 4,5) are found near the 3D/Q-2D interface. The stacking and interface are beneficial for carrier extraction and transport, yielding an external quantum efficiency of 77.9%, a carrier lifetime long as 295.7 ns, and a responsibility of 0.41 A W⁻¹. A low dark current density of 6.2 × 10⁻⁷ mA cm⁻² and a high detectivity of 2.82 × 10¹³ Jones are obtained. Rise time and fall time are fast as 1.33 and 10.1 µs, respectively. The results show the application potential of 3D/Q-2D n-p junction perovskite photodetectors.     

Near‐Infrared and Short‐Wavelength Infrared Photodiodes Based on Dye–Perovskite Composites

Organohalide perovskites have emerged as promising light‐sensing materials because of their superior optoelectronic properties and low‐cost processing methods. Recently, perovskite‐based photodetectors have successfully been demonstrated as both broadband and narrowband varieties. However, the photodetection bandwidth in perovskite‐based photodetectors has so far been limited to the near‐infrared regime owing to the relatively wide band gap of hybrid organohalide perovskites. In particular, short‐wavelength infrared photodiodes operating beyond 1 µm have not yet been realized with organohalide perovskites. In this study, narrow band gap organic dyes are combined with hybrid perovskites to form composite films as active photoresponsive layers. Tuning the dye loading allows for optimization of the spectral response characteristics and excellent charge‐carrier mobilities near 11 cm² V^?1 s^?1, suggesting that these composites combine the light‐absorbing properties or IR dyes with the outstanding charge‐extraction characteristics of the perovskite. This study demonstrates the first perovskite photodiodes with deep near‐infrared and short‐wavelength infrared response that extends as far as 1.6 µm. All devices are solution‐processed and exhibit relatively high responsivity, low dark current, and fast response at room temperature, making this approach highly attractive for next‐generation light‐detection techniques.     

2D Antiferroelectric Hybrid Perovskite with a Large Breakdown Electric Field And Energy Storage Density

Energy conversion and storage devices are highly desirable for the sustainable development of human society. Hybrid organic–inorganic perovskites have shown great potential in energy conversion devices including solar cells and photodetectors. However, its potential in energy storage has seldom been explored. Here the crystal structure and electrical properties of the 2D hybrid perovskite (benzylammonium)₂PbBr₄ (PVK-Br) are investigated, and the consecutive ferroelectric-I (FE1) to ferroelectric-II (FE2) then to antiferroelectric (AFE) transitions that are driven by the orderly alignment of benzylamine and the distortion of [PbBr₆] octahedra are found. Furthermore, accompanied by field-induced AFE to FE transition near room temperature, a large energy storage density of ≈1.7 J cm⁻³ and a wide working temperature span of ≈70 K are obtained; both of which are among the best in hybrid AFEs. This good energy storage performance is attributed to the large polarization of ≈7.6 µC cm⁻² and the high maximum electric field of over 1000 kV cm⁻¹, which, as revealed by theoretical calculations, originate from the cooperative coupling between the [PbBr₆] octahedral framework and the benzylamine molecules. The research clarifies the discrepancy in the phase transition character of PVK-Br and shed light on developing high-performance energy storage devices based on 2D hybrid perovskite.     

H-BN-Encapsulated Uncooled Infrared Photodetectors Based on Tantalum Nickel Selenide

Uncooled broadband spectrum detection, spanning from visible to mid-wave-infrared regions, offers immense potential for applications in environmental monitoring, optical telecommunications, and radar systems. While leveraging proven technologies, conventional mid-wave-infrared photodetectors are encumbered by high dark currents and the necessity for cryogenic cooling. Correspondingly, innovative low-dimensional materials like black phosphorus manifest weak photoresponse and instability. Here, tantalum nickel selenide (Ta₂NiSe₅) infrared photodetectors with an operational wavelength range from 520 nm to 4.6 µm, utilizing a hexagonal boron nitride (h-BN) encapsulation technique are introduced. The h-BN encapsulated metal-Ta₂NiSe₅-metal photodetector demonstrates a responsivity of 0.86 A W⁻¹, a noise equivalent power of 1.8 × 10⁻¹¹ W Hz^−1/2, and a peak detectivity of 8.75 × 10⁸ cm Hz^1/2 W⁻¹ at 4.6 µm under ambient conditions. Multifaceted mechanisms of photocurrent generation in the novel device prototype subject are scrutinized to varying wavelengths of radiation, by characterizing the temporal-, bias-, power-, and temperature-dependent photoresponse. Moreover, the photopolarization dependence is delved and concealed-target imaging is demonstrated, which exhibits polarization angle sensitivity and high-fidelity imaging across the visible, short-wave, and mid-wave-infrared bands. The observations, which reveal versatile detection modalities, propose Ta₂NiSe₅ as a promising low-dimensional material for advanced applications in nano-optoelectronic device.     

High Q-Factor and Low Threshold Continuous-Wave Near-Infrared Lasing with Quasi-2D Perovskites

Quasi-2D perovskites have shown great potential in achieving solution-processed electrically pumped laser diodes due to their multiple-quantum-well structure, which induces a carrier cascade process that can significantly enhance population inversion. However, continuous-wave (CW) optically pumped lasing has yet to be achieved with near-infrared (NIR) quasi-2D perovskites due to the challenges in obtaining high-quality quasi-2D films with suitable phase distribution and morphology. This study regulates the crystallization of a NIR quasi-2D perovskite ((NMA)₂FA_n−1Pb_nI_3n+1) using an 18-crown-6 additive, resulting in a compact and smooth film with a largely improved carrier cascade efficiency. The amplified spontaneous emission threshold of the film is reduced from 47.2 to 35.9 µJ cm⁻². Furthermore, by combining the film with a high-quality distributed feedback grating, this study successfully realizes a CW NIR laser of 809 nm at 110 K, with a high Q-factor of 4794 and a low threshold of 911.6 W cm⁻². These findings provide an important foundation for achieving electrically pumped laser diodes based on the unique quasi-2D perovskites.     

Layered Double Hydroxide with Interlayer Quantum Dots and Laminate Defects for High-Performance Supercapacitor

Owing to the flexible adjustability of laminates, layered double hydroxides (LDHs) can achieve enhanced conductivity and capacitance. However, the regulation of interlayer activity is a great challenge because of the unconquerable charge repulsion between laminates. Herein, a dual-activity design of LDHs is uniquely realized, including laminate defects and interlayer ZnS quantum dots (QDs). Via pre-embedding Zn2+ and controllable vulcanization, ZnS-QDs interpenetrate between CuCo-LDH layers, exposing abundant active sites and widening the layer spacing. Meanwhile, sulfur replaces part of the oxygen on the laminates to form rich oxygen vacancies (CuCo-LDH-S), which does not damage the layered spatial structure and ensures the fast ions/electron transport. Theoretical calculations indicate that the new active centers exhibit higher charge density as compared to CuCo-LDH. Moreover, the copper foam directly provides copper source to ensure that CuCo-LDH-S/ZnS-QDs present a 3D self-supporting structure with ultrastability. Hence, it delivers an ultrahigh capacitance of 7.82 F cm⁻² at 2 mA cm⁻² and 4.43 F cm⁻² at 20 mA cm⁻². The hybrid supercapacitors display an outstanding energy density of 299 µWh cm⁻² at power density of 1600 µW cm⁻², with outstanding capacitance retention of 102.3% and coulomb efficiency of 96.2% after 10 000 cycles.     

Centimeter-Sized Single Crystals of Two-Dimensional Hybrid Iodide Double Perovskite (4,4-Difluoropiperidinium)4AgBiI8 for High-Temperature Ferroelectricity and Efficient X-Ray Detection

Ferroelectricity and X-ray detection property have been recently implemented for the first time in hybrid bromide double perovskites. It sheds a light on achieving photosensitive and ferroelectric multifunctional materials based on 2D lead-free hybrid halide double perovskites. However, the low T_c, small P_s, and relatively low X-ray sensitivity in the reported bromide double perovskites hinder practical applications. Herein, the authors demonstrate a novel 2D lead-free iodide double perovskite (4,4-difluoropiperidinium)₄AgBiI₈ (1) for high-performance X-ray sensitive ferroelectric devices. Centimeter-sized single crystal of 1 is obtained and exhibits an excellent ferroelectricity including a high T_c up to 422 K and a large P_s of 10.5 μC cm⁻². Moreover, due to a large X-ray attenuation and efficient charge carrier mobility (μ)–charge carrier lifetime (τ) product, the crystal 1 also exhibits promising X-ray response with a high sensitivity up to 188 μC·Gy_air⁻¹ cm⁻² and a detection limit below 3.13 μGy_air·s⁻¹. Therefore, this finding is a step further toward practical applications of lead-free halide perovskite in high-performance photoelectronic devices. It will afford a promising platform for exploring novel photosensitive ferroelectric multifunctional materials based on lead-free double perovskites.     

Air-Stable Self-Powered Photodetectors Based on Lead-Free CsBi3I10/SnO2 Heterojunction for Weak Light Detection

Lead halide perovskites (LHPs) have been widely investigated in photodetection applications owing to their intriguing optoelectronic properties. However, the application of LHPs-based photodetectors (PDs) is hindered because of the toxicity of lead and instability in ambient air. Here, an air-stable self-powered photodetector is designed based on all-inorganic lead-free CsBi₃I₁₀/SnO₂ heterojunction. The device exhibits broad spectral response in both UV and visible light, fast response on µs scale, and decent long-term stability. The device holds a faster response speed (t_r/t_d = 7.8/8.8 µs), among the best reported self-powered lead-free perovskites photodetectors. More importantly, the device can display obvious photoresponses even under ultra-weak light intensity as low as 10 pW cm^–2, showing better weak-light sensitivity than previously reported lead-free perovskites photodetectors, to the best of our knowledge. Moreover, the device holds good air stability in the 73 days test without encapsulation. These results suggest that CsBi₃I₁₀/SnO₂-based self-powered PDs with high photodetection capability possess enormous potential in stable and broadband PDs for weak light detection in the future.     

Mixed Ruddlesden–Popper and Dion–Jacobson Phase Perovskites for Stable and Efficient Blue Perovskite LEDs

Producing efficient blue and deep blue perovskite LEDs (PeLEDs) still represents a significant challenge in optoelectronics. Blue PeLEDs still have problems relating to color, luminance, and structural and electrical stability so new materials are needed to achieve better performance. Recent reports suggest using low n states (n = 1, 2, 3) to achieve blue electroluminescence in Ruddlesden–Popper (RP) perovskite films. However, there are fewer reports on the other quasi-2D structure, Dion–Jacobson (DJ) perovksites, despite their highly desirable optical properties, due to the difficulty in achieving charge injection. To resolve this issue, herein, w e have mixed DJ phase precursors, propane-1,3-diammonium (PDA) bromide into RP phase perovskites and fabricated low-dimensional PeLEDs. It is found that these specific precursors aid in suppressing both the low n (n = 1) and high n (n ≥ 4) quasi-2D RP phases and is an effective strategy in blue-shifting sky-blue RP perovskites into the sub-470 nm region. With optimization of the PDA concentration and device layers, it is achieved an external quantum efficiency of 1.5% at 469 nm and stable electroluminescence for the first deep blue PeLED to be reported using DJ perovskites.     

Self-Powered Organic Photodetectors with High Detectivity for Near Infrared Light Detection Enabled by Dark Current Reduction

Organic photodetectors (OPDs) for near infrared (NIR) light detection represents cutting-edge technology for optical communication, environmental monitoring, biomedical imaging, and sensing. Herein, a series of self-powered OPDs with high detectivity are constructed by the sequential deposition (SD) method. The dark currents (J_d) of SD devices are effectively reduced in comparison to blend casting (BC) ones due to the vertical phase segregation structure. Impressively, the J_d values of SD devices based on D18 and Y6 system is reduced to be 2.1 × 10⁻¹¹ A cm⁻² at 0 V, which is two orders of magnitude lower than those of the BC devices. The D* value of the SD device is superior to that of BC device under different bias voltages (0, −0.5, −1.0, and −2.0 V) due to the reduction of dark current, which originates from the fine vertical phase separation structure of the SD device. The mechanism studies shows that the vertical phase segregation structure can effectively suppress the unfavorable charge injection, thus reducing the dark current. Also, the surface energy is proven to play a key role in the photocurrent stability. In addition, the flexible OPDs demonstrate excellent performance in photoplethysmography test.     

Centimeter-Sized Molecular Perovskite Crystal for Efficient X-Ray Detection

Molecular perovskites have demonstrated great potential for ferroelectrics and nonlinear optics; however, their charge transport properties for optoelectronics have rarely been explored. Here, understanding of charge transport behavior of molecular perovskite under X-ray excitation based on centimeter-scale TMCM-CdCl₃ (TMCM⁺, trimethylchloromethyl ammonium) single crystal is demonstrated. The crystal is fabricated from an aqueous solution and exhibits a large bandgap of 5.51 eV, with the valence band maximum mainly dominated by the Cl-p/Cd-d states and the conduction band minimum primarily by Cd-s/Cl-p states. Charge mobility exceeding 40 cm² V⁻¹ s⁻¹ and mobility–lifetime (µτ) product on the order of 10⁻⁴ cm² V⁻¹ for the crystal are observed. These excellent optoelectronic properties translate to an efficient photoresponse under X-ray excitation, with the sensitivity reaching 128.9 ± 4.64 µC Gy_air⁻¹ cm⁻² [fivefold higher than that of the commercialized amorphous selenium (α-Se)] and a low detection limit of 1.06 μC Gy_air⁻¹ s⁻¹ (10 V bias). This work pioneers a superior metal-based molecular perovskite single-crystal based paradigm for optoelectronic investigation, which may lead to the discovery of a new generation of X-ray detection and imaging materials.     

The First Improper Ferroelectric of 2D Multilayered Hybrid Perovskite Enabling Strong Tunable Polarization-Directed Second Harmonic Generation Effect

2D organometallic halide perovskites are recently emerging as a robust family of ferroelectrics, of which their inherent spontaneous polarization (P_s) endows fascinating quadratic nonlinear optical properties. However, up to date, few studies are reported to tune and control the second harmonic generation (SHG) effect in this ferroelectric branch. Herein, the first improper ferroelectric of 2D multilayered hybrid perovskites, (IA)₂(EA)₂Pb₃Br₁₀ ( 1 , where IA is isoamylammonium and EA is ethylammonium), which exhibits a high Curie temperature ( ≈ 371 K) and biaxial ferroelectricity with P_s of 2.2  µ C cm⁻² is reported. Strikingly, its unique in-plane ferroelectricity allows strong tunable SHG properties under the polarized-light. That is, the maximum SHG signals are observed with polarized-light parallel to P_s, while the minimum SHG appears along the vertical direction. This SHG anisotropy creates an extremely large dichroism ratio of ≈ 12, as visualized by 2D color mapping, which is the record-high merit for this type of SHG systems. To the best knowledge, this is the first time to achieve tunable SHG effects through ferroelectric polarization. As a pioneering study, the coupling between the SHG effect and ferroelectricity paves a new direction of 2D hybrid perovskite ferroelectrics toward smart optical device applications.     

A Self-Assembled Vertical-Gradient and Well-Dispersed MXene Structure for Flexible Large-Area Perovskite Modules

Advancing hole transport layers (HTL) to realize large-area, flexible, and high-performance perovskite solar cells (PSCs) is one of the most challenging issues for its commercialization. Here, a self-assembled gradient Ti₃C₂T_x MXene incorporated PEDOT:PSS HTL is demonstrated to achieve high-performance large-area PSCs by establishing half-caramelization-based glucose-induced MXene redistribution. Through this process, the Ti₃C₂T_x MXene nanosheets are spontaneously dispersed and redistributed at the top region of HTL to form the unique gradient distribution structure composed of MXene:Glucose:PEDOT:PSS (MG-PEDOT). These results show that the MG-PEDOT HTL not only offers favorable energy level alignment and efficient charge extraction, but also improves the film quality of perovskite layer featuring enlarged grain size, lower trap density, and longer carrier lifetime. Consequently, the power conversion efficiency (PCE) of the flexible device based on MG-PEDOT HTL is increased by 36% compared to that of pristine PEDOT:PSS HTL. Meanwhile, the flexible perovskite solar minimodule (15 cm² area) using MG-PEDOT HTL achieve a PCE of 17.06%. The encapsulated modules show remarkable long-term storage stability at 85 °C in ambient air (≈90% efficiency retention after 1200 h) and enhanced operational lifetime (≈90% efficiency retention after 200 h). This new approach shows a promising future of the self-assembled HTLs for developing optoelectronic devices.     

One-Source Strategy Boosting Dopant-Free Hole Transporting Layers for Highly Efficient and Stable CsPbI2Br Perovskite Solar Cells

All-inorganic perovskites have emerged as promising photovoltaic materials due to their superior thermal stability compared to their organic–inorganic hybrid counterparts. However, the inferior film quality and doped hole transport layer (HTL) have a strong tendency to degrade the perovskite under high temperatures or harsh operating conditions. To solve these problems, a one-source strategy using the same polymer donor material (PDM) to simultaneously dope CsPbI₂Br perovskite films via antisolvent engineering and fabricating the HTL is proposed. The doping assists perovskite film growth and forms a top–down gradient distribution, generating CsPbI₂Br with enlarged grain size and reduced defect density. The PDM as the HTL suppresses the energy barrier and forms favorable electrical contacts for hole extraction, and assemble into a fingerprint-like morphology that improves the conductivity, facilitating the creation of a dopant-free HTL. Based on this one-source strategy using PBDB-T as PDM, the CsPbI₂Br perovskite solar cell with a dopant-free HTL achieves a power conversion efficiency (PCE) of 16.40%, which is one of the highest PCEs reported among all-inorganic CsPbI₂Br pero-SCs with a dopant-free HTL. Importantly, the devices exhibit the highest thermal stability at 85 °C and operational stability under continuous illumination even with Ag as the top electrode and present good universality.     

A Spacer Cation Assisted Nucleation and Growth Strategy Enables Efficient and High-Luminance Quasi-2D Perovskite LEDs

Quasi-2D Ruddlesden-Popper perovskites receive tremendous attention for application in light-emitting diodes (LEDs). However, the role of organic ammonium spacers on perovskite film has not been fully-understood. Herein, a spacer cation assisted perovskite nucleation and growth strategy, where guanidinium (GA⁺) spacer is introduced into the perovskite precursor and at the interface between the hole transport layer (HTL) and the perovskite, to achieve dense and uniform perovskite films with enhanced optical and electrical performance is developed. A thin GABr interface pre-formed on HTL provides more nucleation sites for perovskite crystal; while the added GA⁺ in perovskite reduces the crystallization rate due to strong hydrogen bonding interacts with intermediates, which promotes the growth of enhanced-quality quasi-2D perovskite films. The ionized ammonium group ( NH₃⁺) of GA⁺ also favors formation of polydisperse domain distribution, and amine or imine ( NH₂ or NH) group interact with perovskite defects through coordination bonding. The spacer cation assisted nucleation and growth strategy is advantageous for producing efficient and high-luminance perovskite LEDs, with a peak external quantum efficiency of over 20% and a luminance up to 100 000 cd m⁻². This work can inform and underpin future development of high-performance perovskite LEDs with concurrent high efficiency and brightness.     

2D Perovskite Single-Crystalline Photodetector with Large Linear Dynamic Range for UV Weak-Light Imaging

Weak-light imaging holds immense significance in various imaging applications. Recently, there has been significant research focused on 2D perovskites for photodetectors (PDs), owing to their superior photoelectric properties. However, the utilization of 2D perovskites for high-performance weak-light detection remains limited, and there is a notable absence of demonstration in weak-light ultraviolet (UV) imaging. Herein, a high-sensitive UV detectors with an ultra-low detection limit for weak-light imaging are demonstrated, utilizing 2D perovskite (PA)₂PbBr₄ (PPB) single crystals (SCs). Leveraging the exceptional quality of SCs, the PPB-based PD exhibits outstanding operational performances, including a low dark current of 0.735 pA, high on/off ratio of 4150 under 263.3 mW cm⁻² illimitation,  and extensive linear dynamic range of 153.61 dB, which is currently the highest reported value among 2D perovskite SC detectors. Notably, PPB PDs demonstrate a remarkable response under 5.49 nW cm⁻² illumination, enabling it to exhibit outstanding photo-response with an excellent detectivity of 2.3 × 10¹³ Jones and responsivity of 2.22 A W⁻¹. Importantly, high-resolution images are successfully obtained under weak-light illumination. These findings underscore the immense potential of 2D perovskite for UV weak-light imaging.     

Fully-Depleted PdTe2/WSe2 van der Waals Field Effect Transistor with High Light On/Off Ratio and Broadband Detection

Due to its unique band structure and topological properties, the 2D topological semimetal exhibits potential applications in photoelectric detection, polarization sensitive imaging, and Schottky barrier diodes. However, its inherent large dark current hinders the further improvement of the performance of the semimetal-based photodetectors. In this study, a van der Waals (vdWs) field effect transistor (FET) composed of semimetal PdTe₂ and transition metal dichalcogenides (TMDs) WSe₂ is fabricated, which exhibits high sensitivity photoelectric detection performance in a wide band from visible light (405 nm) to mid-infrared (5 µm). The dark current and the noise level in the device are greatly suppressed by the effective control of the gate. Benefiting from the extremely low dark current (1.2 pA), the device achieves an optical on/off ratio up to 10⁶, a high detectivity of 9.79 × 10¹³ Jones and a rapid response speed (219 and 45 µs). This research demonstrates the latent capacity of the 2D topological semimetal/TMDs vdWs FET for broadband, high-performance, and miniaturized photodetection.     

Integrating Efficient Optical Gain in High‐Mobility Organic Semiconductors for Multifunctional Optoelectronic Applications

Simultaneously integrating efficient optical gain and high charge carrier mobility in organic semiconductors for multifunctional optoelectronic applications is challenging. Here, a new thiophene/phenylene derivative, 5,5′‐bis(2,2‐diphenylvinyl)‐bithiophene (BDPV2T), containing an appropriate butterfly molecular configuration in a π‐conjugated structure, is designed to achieve both solid‐state emission and charge transport properties. The prepared BDPV2T crystals exhibit excellent light‐emitting characteristics with a photoluminescence quantum yield of 30%, low light‐amplification threshold of 8 kW cm^?2, high optical net gain up to 70 cm^?1, and high charge carrier mobility up to 1 cm² V^?1 s^?1 in their J‐aggregate single crystals. These BDPV2T single crystal characteristics ensure their application potential for photodetectors, field‐effect transistors, and light‐emitting transistors. High optoelectronic performances are achieved with photoresponsivity of 2.0 × 10³ A W^?1 and light on/off ratio of 5.4 × 10⁵ in photodetectors, and efficient ambipolar charge transport (µ_h: 0.14 cm² V^?1 s^?1, µ_e: 0.02 cm² V^?1 s^?1) and electroluminescence characteristics in light‐emitting transistors. The remarkably integrated optoelectronic properties of BDPV2T suggest it is a promising candidate for organic multifunctional and electrically pumped laser applications.     

Wood-Inspired Binder Enabled Vertical 3D Printing of g-C3N4/CNT Arrays for Highly Efficient Photoelectrochemical Hydrogen Evolution

2D nanomaterials are very attractive for photoelectrochemical applications due to their ultra-thin structure, excellent physicochemical properties of large surface-area-to-volume ratios, and the resulting abundant active sites and high charge transport capacity. However, the application of commonly used 2D nanomaterials with disordered-stacking is always limited by high photoelectrode tortuosity, few surface-active sites, and low mass transfer efficiency. Herein, inspired by wood structures, a vertical 3D printing strategy is developed to rapidly build vertically aligned and hierarchically porous graphitic carbon nitride/carbon nanotube (g-C₃N₄/CNT) arrays by using lignin as a binder for efficient photoelectrochemical hydrogen evolution. Arising from the directional electron transport and multiple light scattering in the out-of-plane aligned and porous architecture, the resulting g-C₃N₄/CNT arrays display an outstanding hydrogen evolution performance, with the hydrogen yield up to 4.36 µmol (cm⁻² h⁻¹) at a bias of −0.5 V versus RHE, 12.7 and 41.6 times higher than traditional thick g-C₃N₄/CNT and g-C₃N₄ films, respectively. Moreover, this 3D printed structure can overcome the agglomeration problem of the commonly used g-C₃N₄ with powder configuration and shows desirable recyclability and stability. This facile and scalable vertical 3D printing strategy will open a new avenue to highly enhance the photoelectrochemical performance of 2D nanomaterials for sustainably production of clean energy.     

Transparent and Reusable Nanostencil Lithography for Organic–Inorganic Hybrid Perovskite Nanodevices

Organic—inorganic hybrid perovskites have attracted considerable attention for developing novel optoelectronic devices owing to their excellent photoresponses. However, conventional nanolithography of hybrid perovskites remains a challenge because they undergo severe damage in standard lithographic solvents, which prohibits device miniaturization and integration. In this study, a novel transparent stencil nanolithography (t-SL) technique is developed based on focused ion beam (FIB)-assisted polyethylene terephthalate (PET) direct patterning. The proposed t-SL enables ultrahigh lithography resolution down to 100 nm and accurate stencil mask alignment. Moreover, the stencil mask can be reused more than ten times, which is cost-effective for device fabrication. By applying this lithographic technique to hybrid perovskites, a high-performance 2D hybrid perovskite heterostructure photodetector is fabricated. The responsivity and detectivity of the proposed heterostructure photodetector can reach up to 28.3 A W⁻¹ and 1.5 × 10¹³ Jones, respectively. This t-SL nanolithography technique based on FIB-assisted PET direct patterning can effectively support the miniaturization and integration of hybrid-perovskite-based electronic devices.