Serious performance decline arose for perovskite light-emitting diodes (PeLEDs) once the active area was enlarged. Here we investigate the failure mechanism of the widespread active film fabrication ...method; and ascribe severe phase-segregation to be the reason. We thereby introduce L-Norvaline to construct a COO
-coordinated intermediate phase with low formation enthalpy. The new intermediate phase changes the crystallization pathway, thereby suppressing the phase-segregation. Accordingly, high-quality large-area quasi-2D films with desirable properties are obtained. Based on this, we further rationally adjusted films' recombination kinetics. We reported a series of highly-efficient green quasi-2D PeLEDs with active areas of 9.0 cm
. The peak EQE of 16.4% is achieved in <n > = 3, represent the most efficient large-area PeLEDs yet. Meanwhile, high brightness device with luminance up to 9.1 × 10
cd m
has achieved in = 10 film.
An environmentally friendly mixed‐halide perovskite MA3Bi2Cl9−xIx with a bandgap funnel structure has been developed. However, the dynamic interfacial interactions of bandgap funneling in ...MA3Bi2Cl9−xIx perovskites in the photoelectrochemical (PEC) system remain ambiguous. In light of this, single‐ and mixed‐halide lead‐free bismuth‐based hybrid perovskites—MA3Bi2Cl9−yIy and MA3Bi2I9 (named MBCl‐I and MBI)—in the presence and absence of the bandgap funnel structure, respectively, are prepared. Using temperature‐dependent transient photoluminescence and electrochemical voltammetric techniques, the photophysical and (photo)electrochemical phenomena of solid–solid and solid–liquid interfaces for MBCl‐I and MBI halide perovskites are therefore confirmed. Concerning the mixed‐halide hybrid perovskites MBCl‐I with a bandgap funnel structure, stronger electronic coupling arising from an enhanced overlap of electronic wavefunctions results in more efficient exciton transport. Besides, MBCl‐I's effective diffusion coefficient and electron‐transfer rate demonstrate efficient heterogeneous charge transfer at the solid–liquid interface, generating improved photoelectrochemical hydrogen production. Consequently, this combination of photophysical and electrochemical techniques opens up an avenue to explore the intrinsic and interfacial properties of semiconductor materials for elucidating the correlation between material characterization and device performance.
The interfacial dynamics and electrochemical interactions of hybrid perovskites prepared by an anion‐exchange process in the photoelectrochemical system is investigated through computational simulation, experimental photophysical, and (photo)electrochemical analysis. The synergically interfacial dynamics and electrochemical analysis help to discover the intrinsic and interfacial properties of semiconductor materials.
Mixed‐halide perovskites are considered the most straightforward candidate to realize blue perovskite light‐emitting diodes (PeLEDs). However, they suffer severe halide migration, leading to spectral ...instability, which is particularly exaggerated in high chloride alloying perovskites. Here, we demonstrate energy barrier of halide migration can be tuned by manipulating the degree of local lattice distortion (LLD). Enlarging the LLD degree to a suitable level can increase the halide migration energy barrier. We herein report an “A‐site” cation engineering to tune the LLD degree to an optimal level. DFT simulation and experimental data confirm that LLD manipulation suppresses the halide migration in perovskites. Conclusively, mixed‐halide blue PeLEDs with a champion EQE of 14.2 % at 475 nm have been achieved. Moreover, the devices exhibit excellent operational spectral stability (T50 of 72 min), representing one of the most efficient and stable pure‐blue PeLEDs reported yet.
A new local lattice distortion (LLD) manipulation strategy was demonstrated to suppress the halide migration in mixed‐halide perovskite. DFT simulation and experimental data confirm that the LLD manipulation effectively suppresses the halide migration in perovskites. Mixed‐halide blue PeLED with champion EQE of 14.2 % at 475 nm and impressive T50 of 72 min has been achieved, representing the state‐of‐the‐art pure‐blue PeLEDs.
Solar‐to‐fuel conversion with organic–inorganic hybrid halide perovskites has attracted growing attention as a result of their excellent optoelectronic properties as well as the low temperature of ...the solution based fabrication process. However, the most comprehensively developed hybrid perovskite materials are comprised of the toxic metal lead, raising concerns about environmental health threats. Herein, a lead‐free bismuth (Bi)‐based hybrid perovskite showing in situ growth of heterojunctions is successfully developed at the interface of methylammonium bismuth iodide (MA3Bi2I9) and tri(dimethylammonium) hexa‐iodobismuthate (DMA3BiI6) by a facile solvent engineering technique. The air‐stable MA3Bi2I9/DMA3BiI6 perovskite heterostructure with enhanced photoinduced charge separation exhibit outstanding visible‐light‐induced photocatalytic activity for H2 evolution in aqueous hydrogen iodide solution. The powdered MA3Bi2I9/DMA3BiI6 heterostructured composite (BBP‐5) shows a H2 evolution rate of 198.2 µmol h−1 g−1 without the addition of Pt co‐catalysts under 100 mW cm−2 of visible‐light (λ ≥ 420 nm) illumination.
The heterojunctions of MA3Bi2I9 and DMA3BiI6 hybrid perovskites are constructed using a dimethylformamide‐assisted solvent‐engineering technique, resulting in enhanced solar HI splitting efficiency without any metal co‐catalyst. An in situ formation of perovskite photocatalysts by heterojunction engineering opens a new avenue in the field of solar energy conversion technologies.
Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic ...molecules as the seeds in the chemical vapor deposition (CVD) method. The methodology enables the large‐scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.
A three‐dimensional Ni foam deposited with graphene layers on surfaces is used as a conducting solid support to load MoSx catalysts for electrocatalytic hydrogen evolution. The graphene sheets grown ...on Ni foams provide robust protection and efficiently increase the stability in acid. The superior performance of hydrogen evolution is attributed to the relatively high catalyst loading weight as well as its relatively low resistance.
Infrared solar cells (IRSCs) can supplement silicon or perovskite SCs to broaden the utilization of the solar spectrum. As an ideal infrared photovoltaic material, PbS colloidal quantum dots (CQDs) ...with tunable bandgaps can make good use of solar energy, especially the infrared region. However, as the QD size increases, the energy level shrinking and surface facet evolution makes us reconsider the matching charge extraction contacts and the QD passivation strategy. Herein, different to the traditional sol‐gel ZnO layer, energy‐level aligned ZnO thin film from a magnetron sputtering method is adopted for electron extraction. In addition, a modified hybrid ligand recipe is developed for the facet passivation of large size QDs. As a result, the champion IRSC delivers an open circuit voltage of 0.49 V and a power conversion efficiency (PCE) of 10.47% under AM1.5 full‐spectrum illumination, and the certified PCE is over 10%. Especially the 1100 nm filtered efficiency achieves 1.23%. The obtained devices also show high storage stability. The present matched electron extraction and QD passivation strategies are expected to highly booster the IR conversion yield and promote the fast development of new conception QD optoelectronics.
PbS colloidal quantum dot infrared solar cells can supplement silicon or perovskite solar cells. The energy level evolution of large size PbS quantum dots makes us reconsider the matching charge extraction contacts. The sputtered ZnO based device obtains a certified power conversion efficiency of over 10%, and the 1100 nm filtered efficiency achieves 1.23%.
Photoluminescence (PL) properties of single-layer MoS2 are indicated to have strong correlations with the surrounding dielectric environment. Blue shifts of up to 40 meV of exciton or trion PL peaks ...were observed as a function of the dielectric constant of the environment. These results can be explained by the dielectric screening effect of the Coulomb potential; based on this, a scaling relationship was developed with the extracted electronic band gap and exciton and trion binding energies in good agreement with theoretical estimations. It was also observed that the trion/exciton intensity ratio can be tuned by at least 1 order of magnitude with different dielectric environments. Our findings are helpful to better understand the tightly bound exciton properties in strongly quantum-confined systems and provide a simple approach to the selective and separate generation of excitons or trions with potential applications in excitonic interconnects and valleytronics.
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.
A novel nanostencil lithography technique is developed for fabricating organic—inorganic hybrid perovskite nanodevices. This technique provides ultrahigh lithography resolution down to 100 nm, along with accurate stencil mask alignment and high reusability, which are critical for the development of high‐performance hybrid perovskite optoelectronic devices. Furthermore, this technique can effectively support the miniaturization and integration of hybrid‐perovskite‐based electronic devices.
Antimony sulfide is a promising wide bandgap light‐harvesting material owing to its high absorption coefficient, nontoxicity, superior stability, and low cost. However, the reported Sb2S3 absorber ...suffers from complicated defect characteristics due to its quasi‐1D structure. Herein, a codoping technique from chlorine and selenium is developed in hydrothermal method to regulate the film defect properties and promote the device efficiency. The theoretical calculation and experimental results demonstrate that the Cl&Se codoping plays a synergistic role in absorber film quality improvement. Se doping could efficiently fill the intrinsic deep defect level VS and Cl is a benign n‐type dopant and favor hk1 oriented deposition. Systematic device physical characterizations verify the codoped device superior heterojunction quality and much lower interface and bulk defect density comparing with control one. The optimal codoping device delivers a certified power conversion efficiency of 7.15% (5.9% for control one), the highest certified value in planar Sb2S3 solar cells. This study develops an effective doping strategy with multi‐element synergistic incorporation which sheds new light on high‐efficiency Sb2S3 solar cells.
Sb2S3 is one optimal top‐cell absorption material for Si‐based tandem solar cells. Traditional doping is difficult to achieve efficient heteroatom doping due to complicated defect characteristics. A codoping strategy is developed from Cl and Se doping by hydrothermal method. The synergistic roles of Cl and Se doping help to improve power conversion efficiency from 5.91% (control) to 7.15% (the highest certified value).
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