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Colloidal-Quantum-Dot-in-Perovskite Nanowires
摘要： Colloidal quantum dots are materials of interest in infrared detection – a consequence of their near-infrared light harvesting capability, tunable bandgap, and solution-processing. Herein we develop a quantum-dot-in-perovskite-nanowire consisting of PbS quantum dots embedded inside MAPbI3 nanowires. The kinetics of perovskite nanowire growth were tracked. We found that N, N-dimethylformamide induced the formation of perovskite nanowires, and that their growth was accelerated upon PbS quantum dot inclusion. We then used this nanocomposite to fabricate photodetectors that showed a light response from the visible to near infrared region up to 940 nm. Finally, a flexible photodetector was fabricated on a polyethylene terephthalate substrate.
关键词： MAPbI3 nanowires,flexible photodetector,PbS quantum dots
更新于2025-11-14 17:04:02
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MAPbI3/agarose photoactive composite for highly stable unencapsulated perovskite solar cells in humid environment
摘要： Perovskite solar cells, bearing the merits of facile preparaion and remarkable efficiency, has great potential for bringing the photovoltaic industry to a new generation. The photovoltaic market demands high-efficiency, high stability and low-cost fabrication of perovksite solar cells, especially stability to the humid environment for operation. Here, MAPbI3/agarose photoactive material for humid stable unencapsulated devices has been proposed. These solar cells have been operated in ambient humid environment without glove box, exhibiting efficiency up to 14.66% and retain 90% of its PCE after 1392 h and 60% of initial PCE after 1972 h in ambient humid environment (RH>70%) without encapsulation. FTIR and XPS measurements reveal two critical factors for the improved stability. The molecular level interactions between agarose and MAPbI3 passivates the grain boundaries of perovskite thus preventing its degradation. Moreover, the formation of Li+-agarose complex at the interface between perovskite layer and hole conductive layer, effectively prevents the water uptake of MAPbI3 layer. Both effects of passivation and minimization of hygroscopicity of LiTFSI by agarose lower the decomposition speed of perovskite, which obviously increases the power efficiency and stability of device.
关键词： humid stability mechanism,perovskite solar cells,MAPbI3/agarose photoactive composite
更新于2025-11-14 15:24:45
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Caesium-Incorporated Triple Cation Perovskites Deliver Fully Reversible and Stable Nanoscale Voltage Response
摘要： Perovskite solar cells that incorporate small concentrations of Cs in their A-site have shown increased lifetime and improved device performance. Yet, the development of fully stable devices operating near the theoretical limit requires understanding how Cs influences perovskites’ electrical properties at the nanoscale. Here, we determine how the chemical composition of three perovskites (MAPbBr3, MAPbI3, and Cs-mixed) affects their short- and long-term voltage stabilities, with <50 nm spatial resolution. We map an anomalous irreversible electrical signature on MAPbBr3 at the mesoscale, resulting in local Voc variations of ~400 mV, and in entire grains with negative contribution to the Voc. These measurements prove the necessity of high spatial resolution mapping to elucidate the fundamental limitations of this emerging material. Conversely, we capture the fully reversible voltage response of Cs-mixed perovskites, containing small amounts of Cs, FA, and Br, demonstrating that the desired electrical output persists even at the nanoscale. The Cs-mixed material presents no spatial variation in Voc, as ion motion is restricted. Our results show that the nanoscale electrical behavior of the perovskites is intimately connected to their chemical composition and macroscopic response.
关键词： ion motion,MAPbI3,Cs-mixed perovskite,MAPbBr3,nanoscale voltage,perovskite solar cells,Kelvin probe force microscopy
更新于2025-09-23 15:23:52
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Transparent, flexible MAPbI3 perovskite microwire array passivated with ultra-hydrophobic supramolecular assembly for stable and high-performance photodetectors
摘要： The emergence of organic-inorganic hybrid perovskites (OHPs) has revolutionised the potential performance of optoelectronic devices, most perovskites are opaque and hence incompatible with transparent optoelectronics, and sensitive to environmental degradation. Here, a single-step fabrication of ultra-long MAPbI3 perovskite microwire array over a large-area using stencil lithography based on a sequential vacuum sublimation. The environmental stability of MAPbI3 is empowered a newly designed and synthesized transparent supramolecular self-assembly, based on a mixture of two tripodal L-Phe-C11H23/C7F15 molecules, which showed a contact angle of 105° and served as ultra-hydrophobic passivation layer for more than 45 days in ambient atmosphere. The MAPbI3 microwire array passivated with supramolecular self-assembly demonstrate for the first time both excellent transparency of ~89% at 550 nm and remarkable photoresponse with photo-switching ratio of ~104, responsivity of 789 A/W, detectivity of 1014 Jones, linear dynamic range of ~ 122 dB, and rise time of 432 μs. Furthermore, the photodetector fabricated on flexible PET substrate demonstrated robust mechanical flexibility even beyond 1200 bending cycles. Therefore, the scalable stencil lithography and supramolecular passivation approaches have the potential to deliver next-generation transparent, flexible, and stable optoelectronics.
关键词： transparency,stencil lithography,photodetectors,MAPbI3,supramolecular self-assembly,flexibility,organic-inorganic hybrid perovskites,environmental stability
更新于2025-09-23 15:21:01
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Improving the efficiency of perovskite solar cells using modification of CH3NH3PbI3 active layer: the effect of methylammonium iodide loading time
摘要： In perovskite (PSK) solar cells, the PSK absorber layer plays a vital role in power conversion efficiency (PCE). In this study, we report on the fabrication of mesoporous PSK solar cells using a two-step spin-coating rout with the structure of glass/FTO/compact TiO2/mesoporous TiO2/CH3NH3PbI3 (MAPbI3)/P3HT/Au. The morphology and crystalline structure of the PSK thin film is controlled by changing the CH3NH3I (MAI) loading times (the 20?s, 30?s, 40?s, 60?s) on PbI2 film. The PSK layers are optimized at different MAI loading times in a two-step process to enhance the PCE of the PSK solar cells. The investigation and comparison of the results show that the solar cell containing the absorber layer prepared by solution loading time of the 40?s is more efficient than the other devices. The champion device shows the open-circuit voltage (Voc) of 0.97?V, short current density (Jsc) of 19.30?mA/cm2, and fill factor (FF) of 0.64, which leads to the best PCE of 12.04%.
关键词： MAI loading time,MAPbI3,Perovskite solar cell,CH3NH3PbI3,Spins coating,Active layer
更新于2025-09-23 15:21:01
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Correlation between efficiency and device characterization in MAPbI3-xClx standard perovskite solar cells
摘要： Hybrid organic–inorganic halide perovskite solar cells (PSCs) have gained exceptional attention in photovoltaic fields with an attractive yield of 25%. Characterization tools present as an important means that would help define optimized treatment parameters at an early stage of device manufacturing, instead of measuring the J (V) curves of complete solar cells. In this work, devices with planar NIP architecture ITO/SnO2/MAPbI3-xClx/HTL/Au were elaborated using one-step deposition method. The effects of annealing temperature of the ETL layer (SnO2) and various materials as an HTL layer have been studied. In parallel, X-ray diffraction, UV–visible absorption and photoluminescence were performed as well as photoluminescence spectroscopy, to analyze the active layer crystallinity, absorption properties and to probe charge transfer between perovskite and interface layers. By varying processing parameters, device efficiency could be raised from 10% up to 13.2%.
关键词： SnO2,HTL materials,Perovskite solar cells,Annealing temperature,MAPbI3-xClx,Photovoltaic performance
更新于2025-09-23 15:21:01
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Fabrication of perovskite solar cells in ambient conditions
摘要： Perovskite solar cells (PSCs) are currently a centre of attraction for their excellent photovoltaic properties and low fabrication cost. The ef?ciency of PSCs has reached up to 25% which is comparable to silicon-based solar cells, making them the fastest improving photovoltaic technology. All state-of-the-art PSCs are usually fabricated in inert environment conditions such as in nitrogen-?lled glovebox. In this study, we have fabricated well known conventional n-i-p and inverted p-i-n structures of PSCs having methylammonium lead iodide (MAPbI3) as a perovskite photoactive layer in ambient conditions and provided a comparative study on their photovoltaic properties. The highest power conversion ef?ciency (PCE) for n-i-p and p-i-n structures were found to be 16.79% and 8.06% respectively under AM 1.5 G one-sun illumination conditions (100 mW-cm?2). In addition, to investigate the device stability, the variation of short-circuit current density (JSC) under continuous illumination on both structures has been investigated.
关键词： Ambient conditions,MAPbI3,N-i-p,P-i-n,Perovskite solar cell
更新于2025-09-23 15:19:57
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Full Efficiency Recovery in Hole-Transporting Layer-Free Perovskite Solar Cells With Free-Standing Dry-Carbon Top-Contacts
摘要： Carbon-based top electrodes for hole-transporting-layer-free perovskite solar cells (PSCs) were made by hot press (HP) transfer of a free-standing carbon-aluminum foil at 100?C and at a pressure of 0.1 MPa on a methylammonium lead iodide (MAPbI3) layer. Under these conditions, the perovskite surface was preserved from interaction with the solvent. Over a timescale of 90 days, HP-PSCs were systematically compared to reference cells with carbon-based top electrodes deposited by doctor blading (DB). We found that all the photovoltaic parameters recorded in HP-PSCs during time under ambient conditions settled on values systematically higher than those measured in the reference DB-PSCs, with ef?ciency stabilized at around 6% within the ?rst few measurements. On the other hand, in DB-PSCs, a long-lasting (～14 days) degrading transient of the performances was observed, with a loss of ef?ciency from an initial ～8% to ～3%. Moreover, in HP-PSCs, a systematic day-by-day recovery of the ef?ciency after operation was observed (1～2%) by leaving the cell under open circuit, a nitrogen environment, and dark conditions. Noteworthily, a full recovery of all the parameters was observed at the end of the experiment, while DB-PSCs showed only a partial recovery under the same conditions. Hence, the complete release of solvent from the carbon contact, before an interface is established with the perovskite layer, offers a de?nite advantage through the long period of operation in preventing irreversible degradation. Our ?ndings indeed highlight the crucial role of the interfaces and their feasible preservation under nitrogen atmosphere.
关键词： durability,healing,self-curing,MAPbI3,solvent-free,stability,nitrogen
更新于2025-09-23 15:19:57
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Effect of phase transition stress on the photoluminescence of perovskite CH3NH3PbI3 microwires
摘要： CH3NH3PbI3 (MAPbI3) exhibits distinctive properties for applications in photovoltaics, light emitting devices, photodetectors, and fuel cells. The working temperature of an optoelectronic device affects the photophysical properties of the active material, which is closely related to the device performance. In MAPbI3, these properties are intimately connected with its crystalline structure which is temperature dependent. Here, we study the photoluminescence (PL) behavior of MAPbI3 microwires (MWs) under recursive tetragonal-to-cubic and cubic-to-tetragonal phase transitions induced by temperature cycles from 40 °C (tetragonal phase) to 80 °C (cubic phase). MWs emission exhibited an initial redshift in wavelength by increasing the temperature from the tetragonal to the cubic phase, but after several thermal cycles, this trend reversed and the emission blueshifted. In both phases independently, the emission blueshifted and became stronger with increasing the cycles. The results indicate a thermal cycling-dependent PL and a gradual crystalline structure deformation due to a reiterated change in the MWs lattice, which implies variation in the electronic bandgap along the heating–cooling process. The alteration of the electronic band structure was corroborated by thermal cycling-re?ectance measurements. The awareness behavior of material properties upon phase transitions and temperature ?uctuations is of great importance for the optimization of optoelectronic devices.
关键词： MAPbI3,optoelectronic devices,phase transition,thermal cycling,photoluminescence
更新于2025-09-23 15:19:57
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Photo-oxidative degradation of methylammonium lead iodide perovskite: mechanism and protection
摘要： Although the power conversion efficiency of perovskite solar cells has exceeded 23%, the poor ambient stability of organic–inorganic halide perovskites poses a challenge for their commercialization. Comprehensive understanding of the underlying degradation mechanisms is a crucial step to seek approaches that can effectively suppress the degradation of perovskites. Herein, on the basis of extensive first-principles calculations, a three-step photo-oxidative degradation mechanism of MAPbI3 at the atomic level is revealed. We find that, in a dry ambient environment, the photo-generated superoxide anions (O2?) first lead to fast surface oxidation. However, further oxidation of the perovskite interior is hindered by the solid oxidation product. The fresh water produced in surface oxidation leads to the hydration of the inner perovskite and eventual breakage of the MAPbI3 lattice. We devise a practical strategy for protecting MAPbI3 from photo-induced decomposition by anchoring hydrophobic 2-(4-fluorophenyl)propan-2-amine on the surface of MAPbI3. The surface modification significantly retards the photo-induced decomposition.
关键词： superoxide anions,photo-oxidative degradation,surface modification,perovskite solar cells,MAPbI3,stability
更新于2025-09-19 17:15:36