Interface-Centric Strategies in Kesterite Solar Cells: Addressing Challenges, solutions, and Future Directions for Efficient Solar-Harvesting Technologies.

As reserves of non-renewable energy sources decline, the search for sustainable alternatives becomes increasingly critical. Next-generation energy materials play a key role in this quest by enabling the manipulation of properties for effective energy solutions and understanding interfaces to enhance energy yield. Studying these interfaces is essential for managing charge transport in optoelectronic devices, yet it presents significant challenges.

Amino Acid-Driven Dimensional Reduction of CsPbBr Nanocrystals.

Inspired by biomineralization, the recent incorporation of organic molecules into inorganic lattices shows interesting optical properties and tunability. We functionalize all inorganic CsPbBr perovskite nanocrystals (PNCs) with amino acid (AA) cysteine using the water-hexane interfacial approach. Along with the AA cysteine, we added AuBr salt into the aqueous phase, leading to the formation of a Au-cysteine thiolate complex to activate the aqueous to nonaqueous phase transportation of the AA via a molecular shuttle, oleylamine.

Ultrafast electron shuttling suppresses the energy transfer process in Mn-doped CsPbCl nanocrystals.

Taking advantage of the slow exciton-to-dopant energy transfer process, we dissociated the exciton in Mn-doped perovskite ultrafast electron shuttling to a surface adsorbed 4-nitro phenol molecule. The observed ultrafast electron transfer process is competitive to the ultrafast exciton scattering process (∼140 fs) to the continuum states optical phonons, but three-orders faster than the exciton-to-Mn energy transfer timescale.

Novel Au/CuNiSnS Nano-Heterostructure: Synthesis, Structure, Heterojunction Band Offset and Alignment, and Interfacial Charge Transfer Dynamics.

Considering the importance of physics and chemistry at material interfaces, we have explored the coupling of multinary chalcogenide semiconductor CuNiSnS nanoparticles (CNTS NPs) for the first time with the noble metal (Au) to form Au-CNTS nano-heterostructures (NHSs). The Au-CNTS NHSs is synthesized by a simple facile hot injection method. Synergistic experimental and theoretical approaches are employed to characterize the structural, optical, and electrical properties of the Au-CNTS NHSs.

Size-Tunable Manganese-Doped Spheroidal CsPbCl Quantum Dots.

Manganese doping has been demonstrated as a versatile tool to tune the emission of CsPbCl nanocrystals (NCs). Although this has been demonstrated in nanocubes and nanoplatelets, strategies for doping Mn in size-tunable, excitonic CsPbCl quantum dots (QDs) remain absent. In this work, we demonstrate the synthesis of size-tunable spheroidal CsPbCl:Mn QDs, which can be obtained by a water-hexane interfacial combined anion and cation exchange strategy starting from CsPbBr QDs.

Reversible CsPbBr ↔ CsPbBr Transformation via Reverse Micellar Aqueous Solution.

Lead halide perovskites suffer from water and moisture instability due to the highly ionic nature of the crystal structures, though a few groups took advantage of it for chemical transformation via water-assisted strategy. However, direct exposure of the perovskite to bulk water leads to uncontrolled chemical transformation. Here, we report a controlled chemical transformation of CsPbBr to CsPbBr triggered by nanoconfined water by placing CsPbBr in the nonpolar phase within a reverse micelle.

A Bound Exciton Resonance Modulated by Bulk and Localized Coherent Phonons in Double Perovskites.

Optically excited electronic excitations are coupled to the soft and polar halide perovskite lattice, generating coherent phonons after subpicosecond interband laser-excitation. In Ag-based halide double perovskites, Ag-vacancies can bind free excitons, resulting in a pronounced bound exciton resonance. Here, we report the detection of three modulation frequencies corresponding to coherent phonons in Ag-based double perovskite nanocrystals at distinct spectral positions at the bound exciton resonance.

Obtaining Ligand-Free Aqueous Au-Nanoparticles Using Reversible CsPbBr ↔ Au@CsPbBr Nanocrystal Transformation.

Water-hexane interfacial preparation of photostable Au@CsPbBr (Au@CPB) hybrid nanocrystals (NCs) from pure CsPbBr (CPB) NCs is reported, with the coexistence of exciton and localized surface plasmon resonance with equal dominance. This enables strong exciton-plasmon coupling in these plasmonic perovskite NCs where not only the photoluminescence is quenched intrinsically due to ultrafast charge separation, but also the light absorption property increases significantly, covering the entire visible region. Using a controlled interfacial strategy, a reversible chemical transformation between CPB and Au@CPB NCs is shown, with the simultaneous eruption of larger-size ligand-free aqueous Au nanoparticles (NPs).

Stimulating Phonon Bottleneck Effect in Organic Semiconductors by Charge-Transfer-Mediated J-Aggregation.

Hot carriers rapidly lose kinetic energies on a subpicosecond time scale, posing significant limitations on semiconductors' photon-conversion efficiencies. To slow the hot carrier cooling, the phonon bottleneck effect is constructed prevalently in quantum-confined structures with discrete energy levels. However, the maximum energy separation (Δ) between the energy levels is in a range of several hundred meV, leading to unsatisfactory cooling time.

Breaking AgInTe Quantum Dot Chain to Fabricate AgInTe-ZnS Janus Nanocrystals.

Colloidal multinary chalcogenides (MnCs) have emerged as excellent optoelectronic materials, where S- and Se-based MnCs show considerable progress; however, the Te counterpart suffers from detrimental surface oxidation. Moreover, Te-based I-III-VI MnCs (e.g.

Interfacial band offset engineering with barium-doping towards enhanced performance of all inorganic CsPbIBr perovskite solar cells.

This study investigates the incorporation of Ba at a low concentration into CsPbIBr, resulting in the formation of mixed CsPbBaIBr perovskite films. Photovoltaic devices utilizing these Ba-doped CsPbIBr (Ba-CsPbIBr) perovskite films achieved a higher stabilized power conversion efficiency of 14.07% compared to 11.

Simultaneous Hydrogen Generation and Exciplex Stimulated Emission in Photobasic Carbon Dots.

Photocatalytic water splitting is a promising approach to generating sustainable hydrogen. However, the transport of photoelectrons to the catalyst sites, usually within ps-to-ns timescales, is much faster than proton delivery (∼μs), which limits the activity. Therefore, the acceleration of abstraction of protons from water molecules towards the catalytic sites to keep up with the electron transfer rate can significantly promote hydrogen production.

Giant Exciton Stokes Shift in Interfacially Prepared Cs(Mn/Pb)Cl Alloy Nanoplatelets.

Controlling the reabsorption of light by an emitting material is one of the keys to improving the performance of light-emitting devices. We prepare a set of size-dependent Cs(Mn/Pb)Cl alloy nanoplatelets (NPls) with substantial enhancement in the exciton Stokes shift, reducing the light-reabsorption significantly. We perform interfacial Mn-alloying using a shuttling ligand that transports MnCl from aqueous to nonaqueous phase and delivers it to NPls.

Silver nanoparticle enhanced metal-organic matrix with interface-engineering for efficient photocatalytic hydrogen evolution.

Integrating plasmonic nanoparticles into the photoactive metal-organic matrix is highly desirable due to the plasmonic near field enhancement, complementary light absorption, and accelerated separation of photogenerated charge carriers at the junction interface. The construction of a well-defined, intimate interface is vital for efficient charge carrier separation, however, it remains a challenge in synthesis. Here we synthesize a junction bearing intimate interface, composed of plasmonic Ag nanoparticles and matrix with silver node via a facile one-step approach.

Chemical coupling of halide perovskite nanocrystals with a metal quinolate complex for white light generation.

Herein we report the construction of a white light emitting (WLE) nanocomposite by chemically coupling halide perovskite nanocrystals (HPNCs; , orange-emitting Mn-doped CsPbCl) with a metal quinolate complex (, a cyan-emitting calcium quinolate (CaQ) complex) while keeping their distinct features. The surface chloride of HPNCs coupled with the Ca-metal center of the CaQ complex without altering the morphology, size, and dopant oxidation state of the HPNCs and provided additional environmental stability of the WLE nanocomposite. The photostable solid WLE nanocomposite displays chromaticity of (0.

Halide-Driven Halogen-Hydrogen Bonding versus Chelation in Perovskite Nanocrystals: A Concept of Charge Transfer Bridging.

The choice of surface functionalized ligands to encapsulate semiconductor nanocrystals (NCs) is important for tailoring their optoelectronic properties. We use a small bidentate 8-hydroxyquinoline (HQ) molecule to surface functionalize CsPbX perovskite NCs (X = Cl, Br, I), along with traditional long-chain monodentate ligands. Our experimental results using optical and ultrafast spectroscopy depict a halogen-hydrogen bonding formation in the HQ functionalized CsPbCl and CsPbBr NCs, which act as a charge transfer (CT) bridging for the interfacial hole transfer from the NCs to the HQ molecule as fast as 540 fs.

Water-Triggered Chemical Transformation of Perovskite Nanocrystals.

Recently emerged lead-halide perovskite nanocrystals (PNCs) are promising optoelectronic material due to their easy solution processability, wide range of color tunability, as well as very high photoluminescence quantum yield. Despite their significant success in lab-scale optoelectronic applications, the long-term stability becomes the main issue, hindering them towards commercialization. The highly ionic nature of such lead-halide structure makes them extremely unstable in water and air.

Confined Excitons in Spherical-Like Halide Perovskite Quantum Dots.

Quantum dots (QDs) offer unique physical properties and novel application possibilities like single-photon emitters for quantum technologies. While strongly confined III-V and II-VI QDs have been studied extensively, their complex valence band structure often limits clear observations of individual transitions. In recently emerged lead-halide perovskites, band degeneracies are absent around the bandgap reducing the complexity of optical spectra.

Ultrafast proton transfer of the aqueous phenol radical cation.

Proton transfer (PT) reactions are fundamental to numerous chemical and biological processes. While sub-picosecond PT involving electronically excited states has been extensively studied, little is known about ultrafast PT triggered by photoionization. Here, we employ femtosecond optical pump-probe spectroscopy and quantum dynamics calculations to investigate the ultrafast proton transfer dynamics of the aqueous phenol radical cation (PhOH˙).

Interfacial Manganese-Doping in CsPbBr Nanoplatelets by Employing a Molecular Shuttle.

Mn-doping in cesium lead halide perovskite nanoplatelets (NPls) is of particular importance where strong quantum confinement plays a significant role towards the exciton-dopant coupling. In this work, we report an immiscible bi-phasic strategy for post-synthetic Mn-doping of CsPbX (X=Br, Cl) NPls. A systematic study shows that electron-donating oleylamine acts as a shuttle ligand to transport MnX through the water-hexane interface and deliver it to the NPls.

Observation of intra- and intermolecular vibrational coherences of the aqueous tryptophan radical induced by photodetachment.

The study of the photodetachment of amino acids in aqueous solution is pertinent to the understanding of elementary processes that follow the interaction of ionizing radiation with biological matter. In the case of tryptophan, the tryptophan radical that is produced by electron ejection also plays an important role in numerous redox reactions in biology, although studies of its ultrafast molecular dynamics are limited. Here, we employ femtosecond optical pump-probe spectroscopy to elucidate the ultrafast structural rearrangement dynamics that accompany the photodetachment of the aqueous tryptophan anion by intense, ∼5-fs laser pulses.

State of the Art and Prospects for Halide Perovskite Nanocrystals.

Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications.

Coherent vibrational dynamics reveals lattice anharmonicity in organic-inorganic halide perovskite nanocrystals.

The halide ions of organic-inorganic hybrid perovskites can strongly influence the interaction between the central organic moiety and the inorganic metal halide octahedral units and thus their lattice vibrations. Here, we report the halide-ion-dependent vibrational coherences in formamidinium lead halide (FAPbX, X = Br, I) perovskite nanocrystals (PNCs) via the combination of femtosecond pump-probe spectroscopy and density functional theory calculations. We find that the FAPbX PNCs generate halide-dependent coherent vibronic wave packets upon above-bandgap non-resonant excitation.