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Deep insights into interface engineering by buffer layer for efficient perovskite solar cells: a first-principles study; é?????é??é??????¤aé?3è????μ?±???-?????2?±????é?￠?·￥?¨?????·±??￥???è§￡: ????????§????????????;
摘要： Recent years have seen swift increase in the power conversion efficiency of perovskite solar cells (PSCs). Interface engineering is a promising route for further improving the performance of PSCs. Here we perform first-principles calculations to explore the effect of four candidate buffer materials (MACl, MAI, PbCl2 and PbI2) on the electronic structures of the interface between MAPbI3 absorber and TiO2. We find that MAX (X = Cl, I) as buffer layers will introduce a high electron barrier and enhance the electron-hole recombination. Additionally, MAX does not passivate the surface states well. The conduction band minimum of PbI2 is much lower than that of MAPbI3 absorber, which significantly limits the band bending of the absorber and open-circuit voltage of solar cells. On the other side, suitable bandedge energy level positions, small lattice mismatch with TiO2 surfaces, and excellent surface passivation make PbCl2 a promising buffer material for absorber/electron-transport-layer interface engineering in PSCs. Our results in this work thus provide deep understanding on the effects of interface engineering with a buffer layer, which shall be useful for improving the performance of PSCs and related optoelectronics.
关键词： perovskite solar cells,band alignment,interfacial defect passivation,buffer layer,interface engineering
更新于2025-09-23 15:21:01
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Rational Interface Engineering for Efficient Flexible Perovskite Light-Emitting Diodes
摘要： Although perovskite light-emitting diodes (Pe-LEDs) are promising for next-generation displays and lighting, their efficiency is still considerably below that of conventional inorganic and organic counterparts. Significant efforts in various aspects of the electroluminescence process are required to achieve high-performance PeLEDs. Here, we present an improved flexible PeLED structure based on the rational interface engineering for energy-efficient photon generation and enhanced light outcoupling. The interface-stimulated crystallization and defect passivation of the perovskite emitter are synergistically realized by tuning the underlying interlayer, leading to the suppression of trap-mediated nonradiative recombination losses. Besides approaching highly emissive perovskite layers, the outcoupling of trapped light is also enhanced by combining the silver nanowires-based electrode with quasi-random nanopatterns on flexible plastic substrate. Upon the collective optimization of the device structure, a record external quantum efficiency of 24.5% is achieved for flexible PeLEDs based on green-emitting CsPbBr3 perovskite.
关键词： defect passivation,flexible perovskite light-emitting diodes,perovskite light-emitting diodes,silver nanowires,light outcoupling
更新于2025-09-23 15:21:01
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Potassium Induced Phase Stability Enables Stable and Efficient Widea??Bandgap Perovskite Solar Cells
摘要： The incorporation of potassium can remarkably stabilize wide-bandgap perovskites with a high Br content by the synergistic effect of the formation of 2D K2PbI4 at the grain boundaries and the interstitial occupancy in the perovskite lattices, which can effectively reduce the trap density and inhibit ion migration, thus suppressing the nonradiative recombination and photoinduced phase segregation.
关键词： phase segregation,wide-bandgap perovskite solar cells,potassium incorporation,defect passivation
更新于2025-09-23 15:21:01
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Thermionic Emission-Based Interconnecting Layer Featuring Solvent Resistance for Monolithic Tandem Solar Cells with Solution-Processed Perovskites
摘要： All-perovskite tandem cells have been considered a potential candidate for bringing the power conversion efficiency (PCE) beyond the Shockley– Queisser limit of single-junction device while retaining the advantages of earth-abundant materials and solution processability. However, a challenging issue with regard to realizing such solution-processed devices is the fulfillment of complex and coupled requirements of the interconnecting layer (ICL), including solvent resistance to protect underlying perovskite film, high electrical properties for carrier transport and recombination, and high optical transmission. In this work, a new thermionic emission–based ICL with enhanced solvent resistance features is demonstrated. Fundamentally, the thermionic emission plays a critical role in the electron transport process in the ICL, which is confirmed through both experimental and theoretical studies. Besides achieving high optical transmission and electrical properties, the new ICL chemically protects the underlying perovskite film by introducing a fluoride silane– incorporated polyethylenimine ethoxylated hybrid system that also passivates the surface defects to reduce electrical loss. The monolithic all-perovskite tandem cells demonstrate highest PCE of 17.9% (from current density–voltage scan) and the highest steady-state efficiency is 16.1% for a typical device. Consequently, this work contributes to not only understanding the fundamental mechanism of ICLs but also promotes robust and low-cost photovoltaics.
关键词： monolithic all-perovskite tandem solar cells,solvent resistance,interconnecting layer,thermionic emission,defect passivation
更新于2025-09-23 15:21:01
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Mixed 2D/3D perovskite with fine phase control modulated by a novel cyclopentanamine hydrobromide for better stability in light-emitting diodes
摘要： The mixed 2D/3D perovskite has been proved to be a promising candidate to increase the exciton binding energy in perovskite light-emitting diodes (PeLEDs). However, the complex phase distribution and impurity (usually referring to ligands) limit the stability of the corresponding PeLEDs. Here, a novel molecule, cyclopentanamine hydrobromide (CyPA·HBr), is adopted to construct a mixed 2D/3D perovskite by partial substitution of FA with CyPA, realizing fine phase control for improved device stability. The adoption of CyPA·HBr helps to tune perovskite grain growth and passivate the defect, resulting in high coverage and smooth thin film with improved photoluminescence property. The PeLEDs with an optimized CyPA·HBr concentration of a molar ratio of 40% exhibit a pure green emission with a full width at half maximum of 22 nm, an external quantum efficiency of 6.55%, and a maximum brightness of 9408 cd m?2 simultaneously. Interestingly, the CyPA·HBr-based device shows a half-lifetime two times longer than the one based on the most commonly used ligand of phenethylammonium bromide (PEA·HBr), assigned to the better phase control ability of CyPA·HBr in 2D/3D perovskite. Those results testify the importance of ligands to modulate perovskite phase along with efficient passivation defects for better stability of PeLEDs.
关键词： Phase control,Stability,Perovskite,Light-emitting diode,Defect passivation
更新于2025-09-23 15:21:01
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Passivation of defects in inverted perovskite solar cells by imidazolium-based ionic liquid
摘要： During perovskite film preparation, defects in the film are almost impossible to avoid because of the migration of the halide ions, which is detrimental to achieve high-quality film. In general, the introduction of additive is an effective strategy to control the film morphology and to reduce the defect density. Here, a representative and simplest ionic liquid, 1-methyl-3-propylimidazolium bromide (MPIB), is selected as an additive due to its high conductivity and lone-pair electron in its cation group. Remarkably, the adding of MPIB additive into the perovskite film improves the power conversion efficiency (PCE) from 15.9% of pristine device to 18.2%. With the help of characterization analysis of scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer, etc., two contributions of MPIB additive are addressed: (1) the major one is the passivation of the uncoordinated Pb2+ to reduce the defects in the perovskite film due to the lone-pair electron in its cation group, and (2) the secondary one is beneficial to promote crystal growth to improve the film quality. Hence, this work provides an easy approach to achieve high-performance perovskite solar cell via passivation of the uncoordinated Pb2+ in the perovskite film due to the lone-pair electron in the cation group.
关键词： MPIB,ionic liquid,perovskite solar cells,power conversion efficiency,defect passivation
更新于2025-09-23 15:21:01
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Efficient Defect Passivation of Sb <sub/>2</sub> Se <sub/>3</sub> Film by Tellurium Doping for High Performance Solar Cells
摘要： Defect in a semiconductor dictates carrier transport and recombination, which is one of the critical factors that influences the power conversion efficiency in solar cells. In this study, we demonstrate that the introduction of tellurium is able to fine tune the atomic ratio of Se/Sb in Sb2Se3 thin film, both Se-rich and Sb-rich Sb2Se3 are well obtained. On the ground of device fabrication and deep level defect spectroscopy characterization, we experimentally disclose that Se-rich Sb2Se3 favors the formation of SeSb and VSb defects, while Sb-rich condition benefits the formation of SbSe and VSe defects. With appropriately excess Se in Sb2Se3, a net efficiency improvement of 2% is obtained when compared with the pristine Sb2Se3 based solar cells. Our study provides an effective strategy to manipulate the defect formation in Sb2Se3 solar cell and inspires further improvement in the efficiency of Sb2Se3 solar cells.
关键词： Sb2Se3,defect passivation,tellurium doping,solar cells,carrier transport
更新于2025-09-23 15:19:57
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Thermally Stable Perovskite Solar Cells with Efficiency over 21% via Bifunctional Additive
摘要： The rapid improvements in performance of organic-inorganic perovskite solar cells has been astonishing but its commercialized production requires further achievements on device stability and efficiency. Herein, we introduce a bifunctional additive, biuret, with multiple Lewis base groups to regulate the crystallization process of perovskite crystals and passivate the defects at grain boundaries. Compared with the control, methylammonium lead iodide (MAPbI3), films processed with biuret exhibit increased grain size, reduced trap states density, and more uniform local photoluminescence. The addition of biuret leads to suppressed trap-assisted nonradiative recombination and an efficiency improvement from 18.26% to 21.16%, which is among the highest efficiency for MAPbI3 solar cells with the mesoscopic structure. Meanwhile, as biuret interacts with uncoordinated Pb2+ and iodide from the iodoplumbate complex on two adjacent perovskite grains, the thermal durability of MAPbI3 film is enhanced due to the crosslink through chemical bonding. Under 85°C annealing in nitrogen, the biuret-modified device preserves 94% of its initial efficiency after 12 days while the control cells lose more than half the efficiency.
关键词： crystallization,defect passivation,bifunctional additive,perovskite solar cell,stability
更新于2025-09-23 15:19:57
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Ammonium acetate passivated CsPbI3 perovskite nanocrystals for efficient red light-emitting diodes
摘要： Lead halide perovskite nanocrystals (PNCs) have very recently emerged as promising emitters for their superior optoelectronic properties. However, the defects in perovskite itself make it susceptible to the external environment and internal ion migration, resulting in low photoluminescence quantum yield (PLQY) and poor device efficiency. Herein, we developed a method to reduce the surface defects of PNCs by introducing ammonium acetate in the synthesis of CsPbI3 PNCs. The addition of ammonium acetate can effectively eliminate undesired surface metallic lead cations and dangling bonds, resulting in an enhanced PLQY and stability. The passivated PNCs have an overall up-shift energy level, demonstrating better hole injection efficiency. As a result, the red light-emitting diodes (LEDs) fabricated with the passivated CsPbI3 PNCs achieved an optimal EQE of 10.6% and a maximum brightness of 981 cd/m2, which are 3.1 and 2.4 times that of unpassivated PNCs based devices, respectively.
关键词： CsPbI3 nanocrystals,ammonium acetate,defect passivation,photoluminescence quantum yield,light-emitting diodes
更新于2025-09-23 15:19:57
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Amphoteric imidazole doping induced large-grained perovskite with reduced defect density for high performance inverted solar cells
摘要： Intrinsic defect density in polycrystalline halide perovskite films are required to be low enough to suppress charge recombination loss for improvement in performance of perovskite solar cells (PeSCs). In this paper, we propose the use of amphoteric imidazole to achieve high crystalline quality of CH3NH3PbI3 perovskite absorption layer. The imidazole additive plays a synergistic role in controlling the perovskite crystal growth for large grain size and passivating the uncoordinated ions (e.g., Pb2+) defects, resulting in improved carrier transport/lifetime and suppressed non-radiative recombination. The champion power conversion efficiency (PCE) of PeSCs with imidazole is improved to 16.88%, from the control device with a PCE value of 14.65%. Besides, the stability of imidazole modified perovskite films is further improved by limiting ion immigration at grain boundaries against moisture and heat stresses. The findings pave an avenue for synergistically modulating crystallization and healing defect in perovskite to achieve efficient and stable solar cells.
关键词： Defect passivation,CH3NH3PbI3,Grain boundary,Inverted solar cell,Non-radiative recombination
更新于2025-09-23 15:19:57