Ahmed Lutfi Abdelhady

The integration of hole-transporting organic interfacial modifying layers (OIMLs) into perovskite solar cells (PSCs) has attracted significant interest due to their ability to improve performance and stability. However, the development of cost-effective and straightforward methods for synthesizing OIMLs remains underexplored. In this work, we present the design and synthesis of two novel bromoaryl-substituted, imidazole-derived OIMLs: 2,4,5-tris(4-bromophenyl)-1H-imidazole (TPIM-Br) and 4,5-bis(4-bromophenyl)–2-(5-bromothiophen-2-yl)-1H-imidazole (DPIM-TBr). We investigated the thermal, optical, and electrochemical properties of the molecules, confirming their potential as OIMLs in PSCs. The computed energy levels and electrostatic surface potentials (ESPs) of these molecules were examined to elucidate the charge distribution and electron density within TPIM-Br and DPIM-TBr. Comprehensive characterization demonstrated that incorporation of the OIMLs enabled more efficient charge extraction and improved perovskite crystallinity. The champion device yielded 25.85% power conversion efficiency for TPIM-Br, compared to the control's 23.32%. This work presents a strategy to enhance the performance of inverted PSCs by incorporating OIMLs, offering a promising pathway for future developments in PSC technology.

Solution‐processed chemical mixing of graphene‐related materials can improve the charge extraction and stability of perovskite materials and devices. In this study, we synthesize MAPbBr ₃ /reduced graphene oxide (rGO) composites using room‐temperature‐based solvent acidolysis crystallization technique. The dispersion of flake‐like rGO gets incorporated into cubic perovskites, enabling interactions between the oxygen‐containing species of rGO and the perovskite, resulting in interfacial electronic restructuring and complete quenching of the photoluminescence (PL). As active layers in photodetectors, these composites demonstrate significantly higher photocurrent, along with a four order of magnitude increase in responsivity and two orders of magnitude increase in detectivity compared to MAPbBr ₃ . This is attributed to more efficient exciton dissociation and favorable energy level alignment with ITO (indium‐doped tin oxide) electrodes. In addition, the time required for the initial photocurrent to drop to 80% ( T ₈₀ ) under continuous illumination under ambient air increases from 0.5 to 3 min, highlighting the critical role of rGO in enhancing the photostability. This work demonstrates the significant effect of rGO composites in developing more efficient and stable perovskite‐based photodetectors.

Solvent engineering provides a route to control both materials chemistry and interfacial properties in perovskite-based devices. In this study, we employ N -methylformamide (NMF) both as a solvent to exfoliate bulk MoS ₂ and as a source of the methylammonium cations, through its acidolysis, enabling the in-situ formation of MoS ₂ -perovskite heterostructures. The exfoliated MoS ₂ remained well-dispersed post-perovskite crystallization, as confirmed by absorbance spectra. Additionally, the presence of MoS ₂ resulted in larger perovskite crystals with less strain compared to control samples. The MoS ₂ -MAPbBr ₃ heterostructure films exhibit approximately 55% photoluminescence quenching, an order of magnitude lower trap density (10 ¹⁰ cm ⁻³ ), more than two-fold enhancement in the charge carrier mobility (346 cm ² V ⁻¹ s ⁻¹ ), and enhanced charge carrier concentration reaching 1.9 × 10 ¹² cm ⁻³ compared to the control MAPbBr ₃ (0.8 × 10 ⁹ cm ⁻³ ). Photodetectors based on MoS ₂ -MAPbBr ₃ heterostructure and pristine MAPbBr₃ devices are explored. Under 488 nm laser illumination (0.02 mW/cm ² ), the MoS ₂ -MAPbBr ₃ device demonstrates responsivity values nearly three times higher than the control devices, along with an external quantum efficiency exceeding 500%. These results highlight the dual role of exfoliated MoS ₂ in MAPbBr ₃ heterostructure films as an effective passivation and charge carrier transport layer, suppressing trap-assisted recombination and facilitating charge transport.

This study presents the design and synthesis of imidazole based, metal free TPIM (1) molecules with short π conjugation and triphenylamine (TPA) decorated TPIM 2D (2) molecules featuring extended π...

Lead halide perovskites APbX₃ (A = methylammonium, formamidinium, cesium; X = halogen) have advanced the field of optoelectronics, particularly in solar cells, photodetectors, and light-emitting diodes, due to their outstanding properties. However, a significant challenge remains unresolved: the formation of metallic lead (Pb⁰), which introduces deep-level defects that trap charge carriers and degrade device performance. The formation of Pb⁰ in perovskites can occur after their synthesis under various conditions, including high-energy radiation, light, heat, and moisture, and has also been observed during perovskite crystallization. Thus, it is crucial to understand the underlying mechanisms of Pb⁰ formation and its suppression pathways. Recent studies have explored various strategies to suppress Pb⁰ formation, including compositional engineering, additive incorporation, and protective passivation layers. In this review, we discuss the origins of Pb⁰ formation in perovskites, focusing on the mechanisms driving this process under different environmental conditions, and then strategies for suppressing Pb⁰ formation, including compositional engineering and passivation techniques. By addressing these aspects, we seek to identify pathways for enhancing the stability and performance of perovskite-based devices, enabling their widespread adoption in commercial applications.

The study presents the total structure and gram scale synthesis of a 32-atom AgCu alloy nanocluster [Ag₄Cu₂₈H₆(PET)₁₆Cl₈(PPh₃)₈][BF₄]₂, which shows excellent catalytic activity in the hydrogenation of hazardous nitroarenes.

Here, we report the solvent-induced polymorphism in [Cu₁₅(PET)₁₃(TPP)₆][BF₄]₂(Cu₁₅) (TPP = triphenylphosphine, PET = 2-phenylethanthiol), and double-helical assembly of the [Cu₁₈H(PET)₁₄(TPP)₆Cl₃] (Cu₁₈) nanocluster (NC) from reaction intermediates. Both copper NCs have an intrinsically chiral triple-stranded helicate metal core, unlike traditional copper NCs with a polyhedral-based kernel. The chiral structure of Cu₁₅ resembles an enantiomeric pair in the unit cell. Moreover, Cu₁₈ has a three-layered 3D chirality of a sandwich constructed of sulfur-bridged copper NCs aligned in a top-middle-down configuration. Furthermore, the Cu₁₈ NC self-hierarchically assembles into a complex double-stranded helix secondary structure sustained by noncovalent interactions. Electrospray ionization mass spectrometry (ESI-MS), density functional theory (DFT), and X-ray photoelectron spectroscopy (XPS) were utilized to validate the single-crystal X-ray diffraction (SCXRD) data. Overall, this study provides an interesting example of polymorphism, chirality, and hierarchical double-helical assembly of NCs, allowing for extensive understanding of complicated structures at the atomic level.

The ternary strategy boosts the performance of organic photovoltaics (OPVs) by optimizing light-harvesting, blend morphology, and energy level alignment. Three novel non-fullerene acceptors (NFAs), IN-DTPT-b20 (1), IN^F-DTPT-b20 (2), and IN^Cl-DTPT-b20 (3), have been designed and synthesized. These NFAs feature a dithienopyrrolothiophene (DTPT)-based fused ring core with soluble branched alkyl side chains and indanone-based end groups, which are functionalized with different halogens (H, F, Cl) to modulate the electronic properties of the NFAs. A comparative study of the thermal, optical, electrochemical, and computed electronic structural properties of compounds 1–3 was conducted. We investigated the optoelectronic properties of PM6:Y6 based OPV in the presence of 1–3 as third component. Following optimization, the power conversion efficiency (PCE) of the ternary OPV based on IN-DTPT-b20 (1) was significantly enhanced from 15.17 ± 0.28% (PM6:Y6) to 16.20 ± 0.26%. Tapping-mode atomic force microscopy (AFM) and grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis confirmed that incorporating IN-DTPT-b20 (1) into PM6:Y6 blend films effectively tailored the blend morphology, particularly by modulating the preferred orientation of Y6. The optimized morphology resulted in enhanced carrier mobility, reduced trap-assisted recombination, and efficient charge collection. These findings demonstrate the effectiveness of our NFA design strategy, further bolstered by the incorporation of IN-DTPT-b20 (1) as a guest acceptor, for achieving efficient OPV.