- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Mn-doped 2D Sn-based perovskites with energy transfer from self-trapped excitons to dopants for warm white light-emitting diodes
摘要： Mn-doped 2D perovskite powders are promising phosphors for warm white light-emitting diodes (LEDs). However, it remains a challenge to solve the problem of lead toxicity and improve photoluminescence quantum yields (PLQYs). Here, we have successfully prepared Mn-doped 2D Sn-based perovskite materials ((C8H17NH2)2Sn1-xMnxBr4). The PLQYs of (C8H17NH2)2Sn1-xMnxBr4 (x = 0.26) powders reach up to 42%. The as-prepared (C8H17NH2)2Sn1-xMnxBr4 exhibit a single broad photoluminescence (PL) band, differing from the dual peaks of Mn-doped lead halide perovskite quantum dots. Theoretical conclusions and experimental results show the competitive relationship between self-trapped excitons (STEs) emission from the host crystal and dopant Mn d-d transition emission. With Mn dopant concentration increasing, the PL spectra exhibit red shifts and the full width at half-maximum (FWHM) turns larger, which is constructive for warm white LEDs. The fabricated warm white LEDs based on (C8H17NH2)2Sn1-xMnxBr4 show warm white light correlated color temperature (CCT, 3542 K) and high color-rendering index (Ra, 88.12). Our work provides new possibilities for optoelectronic devices based on lead-free perovskite materials.
关键词： self-trapped excitons,Mn-doped,photoluminescence quantum yields,2D Sn-based perovskites,warm white light-emitting diodes
更新于2025-09-23 15:21:01
-
Exploring the Carrier Dynamics in Zinc Oxide-Metal Halide Based Perovskites Nanostructures: Towards Reduced Dielectric Loss and Improved Photocurrent
摘要： Metal-halide based perovskites have emerged as a potential candidate for optoelectronic applications due to their impressive performance achieved by tuning the optical/electrical properties through tailoring the perovskite nanostructures. Herein, we report the synthesis of composite nanostructures by incorporation of ZnO (~6 nm) into CsPbBr3 (CPB) perovskite framework, which has significant enhancement of photocurrent, due to efficient interfacial charge separation and reduced dielectric loss. Detailed steady state and time resolved PL studies have been carried out to understand charge transfer dynamics in CsPbBr3/ZnO nanostructure composite system. Femtosecond transient absorption and broadband dielectric spectroscopy studies were carried out to determine the charge carrier relaxation and transfer mechanism. Redox energy level diagram suggests photo-excited electron from conduction band (CB) CPB can be transferred to the CB of ZnO NP due to thermodynamic viability. Ultrafast studies reveal the electron transfer take place from the perovskite nanostructures to ZnO NP within ～500 fs and limits of the recombination process by efficient charge separation and charge accumulation at the interfaces. Dielectric studies also reveal reduced charge leakage in composite nanostructures with efficient charge separation by facilitating the charge accumulation at the interfaces. Overall, the efficient charge transfer and slow carrier recombination with reduced dielectric losses significantly improved the photocurrent behavior CsPbBr3/ZnO nanostructure composite system as desired for optoelectronic devices.
关键词： ZnO,charge transfer dynamics,optoelectronic applications,dielectric loss,photocurrent,Metal-halide based perovskites,CsPbBr3
更新于2025-09-23 15:21:01
-
Large organic cation incorporation induces vertical orientation growth of Sn-based perovskites for high efficiency solar cells
摘要： The potential toxic issue of lead content is still a problem for prohibiting the commercialization of lead halide perovskite solar cells (PSCs). as an element of group 14 metals, tin (Sn) is the most likely substitute for lead element in perovskites. However, Sn-based PSCs still suffer from the low power conversion efficiency (PCE) because Sn2+ in tin-based perovskites is easily oxidized into Sn4+ once exposed to air. To fabricate stable and efficient Sn-based PSCs, herein we incorporate large ethylammonium (EA+) cation into CH3NH3SnI3 (MASnI3) abided by the Goldschmidt tolerance factor to fabricate vertically oriented 2D/3D mixed perovskite films. The vertically oriented structure provides a direct pathway for electron and hole transport. As a result, the PCE is highly improved to 9.24% and the corresponding PSC still retains 95% of the initial efficiency after being kept for 30 days without encapsulation in the glovebox. Therefore, our results suggest a promising strategy to develop highly efficient and stable Sn-based PSCs.
关键词： high efficiency solar cells,Sn-based perovskites,vertical orientation growth,stability,ethylammonium incorporation
更新于2025-09-23 15:19:57
-
Synthesis, characterization of ((CH3)3S)2SnI6-nCln and ((CH3)3S)2SnI6-nBrn (n=1, 2) perovskites and use in dye-sensitized solar cells
摘要： New air-stable ((CH3)3S)2SnI6-nCln and ((CH3)3S)2SnI6-nBrn (n=1, 2) defect perovskites were synthesized and their physicochemical properties were established. Rietveld analysis on the recorded XRD patterns revealed the presence of cubic structural modification with a 0D network of [SnI6-nCln] and [SnI6-nBrn] octahedra. The vibrational and electronic properties of the mixed-anion based trimethylsulfoinum Tin (IV) perovskites investigated using Raman and UV–vis spectroscopy showed that upon substitution of Cl/Br for I, the electronic band gap slightly increased, while the lattice vibrations were also largely affected. Density functional theory (DFT) calculations permitted to determine the density of states (DOS) distribution and corresponding band energy structures, confirming the obtained increase of direct band gap values with halogen substitution. The lead-free Sn(IV)-based compounds were successfully incorporated as hole transporting materials (HTMs) in sensitized nanocrystalline solar cells (DSCs). For these devices, power conversion efficiencies as high as 5% were obtained, under 1 sun (A.M. 1.5G) illumination. Electrochemical impedance spectroscopic analysis indicated that the maximum device performance is associated with high charge recombination resistance and low electron transfer resistance at dye/perovskite and perovskite/Pt interfaces, respectively.
关键词： nanocrystalline solar cells,Sn-based Perovskites,DFT calculations.,hole-transporting material
更新于2025-09-19 17:13:59