A5067954967- Perovskite Materials and Applications
- Conducting polymers and applications
- Organic Light-Emitting Diodes Research
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Technostress in Professional Settings
- Organic Electronics and Photovoltaics
- Advanced MEMS and NEMS Technologies
- Radio Frequency Integrated Circuit Design
- Electronic and Structural Properties of Oxides
- Semiconductor materials and interfaces
- Solar Thermal and Photovoltaic Systems
- Photovoltaic System Optimization Techniques
- Analog and Mixed-Signal Circuit Design
- Experimental Learning in Engineering
- Force Microscopy Techniques and Applications
- Energy Harvesting in Wireless Networks
- Wireless Power Transfer Systems
- Nanofabrication and Lithography Techniques
- Solid-state spectroscopy and crystallography
- Nanowire Synthesis and Applications
École Polytechnique Fédérale de Lausanne
2024
The University of Texas at Dallas
2019-2023
The University of Texas at El Paso
2017-2019
Abstract Perovskite light‐emitting diodes (PeLEDs) are advancing because of their superior external quantum efficiencies (EQEs) and color purity. Still, additional work is needed for blue PeLEDs to achieve the same benchmarks as other visible colors. This study demonstrates an extremely efficient PeLED with a 488 nm peak emission, maximum luminance 8600 cd m −2 , EQE 12.2% by incorporating double‐sided ethane‐1,2‐diammonium bromide (EDBr 2 ) ligand salt along long‐chain methylphenylammonium...
Perovskite light-emitting diodes (PeLEDs) have drawn considerable attention for their favorable optoelectronic properties. electrochemical cells (PeLECs)—devices that utilize mobile ions—have recently been reported but yet to reach the performance of best PeLEDs. We leveraged a poly(ethylene oxide) electrolyte and lithium salt in CsPbBr3 thin films produce PeLECs improved brightness efficiency. In particular, we found single-layer PeLEC from CsPbBr3:PEO:LiPF6 with 0.5 wt % LiPF6 produced...
Abstract Hybrid organic–inorganic perovskite light‐emitting devices (LEDs) have recently shown the characteristic dynamical behavior of electrochemical cells (LECs), with intrinsic ionic migration creating an electric double layer and internal p‐i‐n structure by accumulation ions at interfaces. Therefore, development photovoltaic based on concepts LEC operation attracts much attention clarifies general physical processes in perovskites. Here, new directions that can further improve...
The 0D cesium lead halide perovskite Cs4 PbBr6 has drawn remarkable interest due to its highly efficient robust green emission compared 3D CsPbBr3 counterpart. However, seizing the advantages of superior photoluminescence properties for practical light-emitting devices remains elusive. To date, been employed only as a higher-bandgap nonluminescent matrix passivate or provide quantum/dielectric confinement in and enhance photo-/thermal/environmental stability. resolve this disparity, novel...
The presence of defects at the interface between perovskite film and carrier transport layer poses significant challenges to performance stability solar cells (PSCs). Addressing this issue, we introduce a dual host-guest (DHG) complexation strategy modulate both bulk interfacial properties FAPbI
Abstract Hybrid perovskites are emerging as highly efficient materials for optoelectronic applications, however, their operational lifetime has remained a limiting factor continued progress. In this work, perovskite light emitting electrochemical cells utilizing an optimized fraction of lithium hexafluorophosphate (LiPF 6 ) salt additive exhibit enhanced stability. At 0.5 wt% LiPF , devices 100 h operation at high brightness in excess 800 cd m −2 under constant current driving, achieving...
Abstract Blue electroluminescence is highly desired for emerging light‐emitting devices display applications and optoelectronics in general. However, saturated, efficient, stable blue emission has been challenging to achieve, particularly mixed‐halide perovskites, where intrinsic ion motion halide segregation compromises spectral purity. Here, CsPbBr 3− x Cl polyelectrolytes, a salt additive are leveraged demonstrate pure from single‐layer electrochemical cells (LECs). The electrolytes...
Abstract Light‐emitting electrochemical cells (LECs) are devices that utilize efficient ion redistribution to produce high‐efficiency electroluminescence in a simple device architecture. Prototypical polymer LECs three components the active layer: luminescent conducting polymer, salt, and an electrolyte. Similarly, many small‐molecule also electrolyte disperse salts. In these systems, is incorporated efficiently conduct ions maintain phase compatibility between all components. However,...
Compared to zero-dimensional (0D) semiconductor quantum dots, 2D nanoplatelets (NPLs) offer a spectrally narrow luminescence and superior absorption coefficients, which makes this geometry an attractive candidate for optoelectronic applications. However, optical devices based on NPLs still suffer from nonradiative Auger decay of multiple excitons (MX), limits the efficiency processes, including MX luminescence, electroluminescence, gain. Here, we demonstrate that recombination is strongly...
Perovskite light-emitting devices have drawn considerable attention for their favorable optoelectronic properties. High carrier mobilities make perovskites excellent candidates as host materials in electroluminescent devices, but yet to be brought full potential this role. To achieve high performance a simple single-layer device, we employed CsPbBr3 perovskite and novel ionic iridium complex guest along with polyelectrolyte demonstrate efficient electrochemical cells (PeLECs). For an optimal...
Electron transport layer (ETL) in perovskite-based solar cells (PSCs) is attractive from the perspective of photon-to-electron conversion efficiency. TiO2 thin film preferred situations where microstructure, stability and charge characteristics are important. In this regard, we illustrate an approach that involves synthesis TiO2–pepsin can be used either as a mesoporous or compact depending on device architecture PSC devices. It was observed pepsin acts organic glue to nanoparticles...
Blue electroluminescence is fundamental for many optoelectronic and lighting applications, mixed halide perovskite light-emitting devices are under development to meet the technological demands. However, stability of blue lacking, primarily because segregation during operation that degrades underlying structure. Saturated stable emission was accomplished with a rational materials blend perovskite, polymer electrolytes, lithium salt selectively suppressed ion motion while facilitating...
As halide perovskite materials have emerged at the forefront of optoelectronics development, there is an ongoing need to understand their underlying physics and control emergent properties. Electrochemistry shows promise both access fundamental parameters perovskites enhance performance through doping. However, pose a significant challenge solution-based electrochemistry, as aqueous solutions organic solvents are often destructive thin films these materials. This work provides perspective...
The remarkable defect-tolerant nature of inorganic cesium halide perovskites, leading to near unity photoluminescence (PL) quantum yield and narrow emission line width across the entire visible spectrum, has provided a tantalizing platform for development plethora light-emitting applications. Recently, lower-dimensional (2D, 1D, 0D) perovskites have attracted further attention due their enhanced thermal, photo, chemical stability as compared three-dimensional (3D) analogues. combination...
Solution processed organic–inorganic metal halide perovskite based solar cells are emerging as a new cost effective photovoltaic technology. In the context of increasing power conversion efficiency (PCE) and sustainability (PSC) devices, we comprehensively analyzed physics-based numerical modelling for doped un-doped PSC devices. Our analytics emphasized role different charge carrier layers from view point interfacial adhesion its influence on extraction rate recombination mechanism....
Organic–inorganic halide perovskites have rapidly become emerging materials for photovoltaic applications, but a major factor causing instability in perovskite solar cells could be the elemental shift due to oxygen. The present work demonstrates oxidation states of layers formed by (i) one-step deposition, (ii) solvent-to-solvent extraction, (iii) hot casting, and (iv) mixed-cation solution processing. X-ray photoelectron spectroscopy is used investigate compositional changes oxygen, spectra...
Solution processed organic–inorganic metal halide perovskite and its derivatives are promising in the development of efficient thin film photovoltaic devices. In context increasing efficiency sustainability solar cells (PSC) devices, we have attempted to experimentally develop phase diagram for solution methyl ammonium lead iodide (CH3NH3PbI3 (MAPbI3)) perovskite. The emphasized role processing parameters (precursor composition crystallization temperature) on crystallographic functionality...
Dilute-donor (DD) organic photovoltaic (OPV) devices comprise a low concentration of donor molecules in an acceptor matrix. The open-circuit voltage (Voc) these is commonly higher than their bulk heterojunction (BHJ) counterparts and has been attributed to Schottky barrier heights between the anode matrix or reduced bimolecular recombination due smaller donor/acceptor interfacial areas. Here, we examine Voc variety small-molecule polymer donors, all at 5 wt %, both fullerene non-fullerene...
Perovskite light-emitting electrochemical cells (PeLECs) utilize ionic redistribution to emit light efficiently from single layer devices. As demonstrated by Jason D. Slinker and co-workers in article number 2000226, PeLECs show 100 h operation excess of 800 cd m−2 extrapolated lifetimes 6700 at with an optimal concentration a lithium salt additive. Electrochemical impedance spectroscopy reveals additives enhance efficiency through improved electrical double formation.
Organic-inorganic perovskite light-emitting devices have recently emerged as a reliable light source. Here, we developed Single Layer Perovskite Light-Emitting Electrochemical Cells (SL-PeLEC) with laminated free-standing Carbon Nanotube Sheet (CNT) sheets an effective charge electron injecting cathode electrode. The structure consists of bottom ITO-on-glass transparent electrode, the composite CsPbBr<sub>3</sub>:PEO:LiPF<sub>6</sub> additive ionic salt emitting layer (EML) and 5 layers CNT...
Perovskites are emerging as excellent candidates for light-emitting devices, and perovskite electrochemical cells (PeLECs) excel because of their superior in-class stability due to the selective redistribution additive ions. Here, understand interplay ionic, electronic, optical effects assess low-temperature CsPbBr3 PeLEC we measured temperature-dependent current, electroluminescence, photoluminescence investigated phase changes by differential scanning calorimetry electron microscopy. The...