Enhancing Perovskite Solar Cell Performance through Propylamine Hydroiodide Passivation.

In recent years, the power conversion efficiency of perovskite solar cells has increased rapidly. Perovskites can be prepared using simple and cost-effective solution methods. However, the perovskite films obtained are usually polycrystalline and contain numerous defects.

observation of thermal-driven structural transitions of a β-NaYF single nanoparticle aided with correlative cathodoluminescence electron microscopy.

NaYF systems have been widely studied as up-conversion host matrices, and their phase transitions are flexible and worth investigating in great detail. Herein, the evolution of morphology and crystal structure of a Eu-doped β-NaYF single nanoparticle heated in an air atmosphere was investigated using transmission electron microscopy (TEM). The annealing process revealed that the hexagonal β-NaYF phase undergoes sequential transformations into high-temperature cubic phases at both 350 °C and 500 °C.

Bridging the Buried Interface with Piperazine Dihydriodide Layer for High Performance Inverted Solar Cells.

Given that it is closely related to perovskite crystallization and interfacial trap densities, buried interfacial engineering is crucial for creating effective and stable perovskite solar cells. Compared with the in-depth studies on the defect at the top perovskite interface, exploring the defect of the buried side of perovskite film is relatively complicated and scanty owing to the non-exposed feature. Herein, the degradation process is probed from the buried side of perovskite films with continuous illumination and its effects on morphology and photoelectronic characteristics with a facile lift-off method.

Rinsing Intermediate Phase Strategy for Modulating Perovskite Crystal Growth and Fabricating Highly Efficient and Stable Inverted Solar Cells.

During the fabrication of metal halide perovskite films, polycrystal growth and maturation are largely influenced by high-temperature annealing. However, this process would cause crystals to expand or contract at various depths in the film, leading to microscopic structural deformation and further altering the optoelectronic properties of the perovskite film. Herein, we propose an additional rinsing intermediate phase (RIP) strategy that involves precovering the perovskite film surface with a mixed organic layer prior to high-temperature annealing.

Optimization of a SnO-Based Electron Transport Layer Using Zirconium Acetylacetonate for Efficient and Stable Perovskite Solar Cells.

SnO is a promising material for use as an electron transfer layer (ETL) in perovskite photovoltaic devices due to its suitable energy level alignment with the perovskite, high electron mobility, excellent optical transmission, and low-temperature processability. The development of high-quality SnO ETLs with a large coverage and that are pinhole-free is crucial to enhancing the performance and stability of the perovskite solar cells (PSCs). In this work, zirconium acetylacetonate (ZrAcac) was introduced to form a double-layered ETL, in which an ideal cascade energy level alignment is obtained.

Electronic and Optical Properties of van der Waals Heterostructures Based on Two-Dimensional Perovskite (PEA)PbI and Black Phosphorus.

Combining two-dimensional (2D) perovskites with other 2D materials to form a van der Waals (vdW) heterostructure has emerged as an intriguing way of designing electronic and optoelectronic devices. The structural, electronic, and optical properties of the 2D (PEA)PbI/black phosphorus (BP) [PEA:(CHNH)] vdW heterostructure have been investigated using first-principles calculations. We found that the (PEA)PbI/BP heterostructure shows a high stability at room temperature.

High-Performance Photovoltaic Materials Based on the Superlattice Structures of Organic-Inorganic Halide Perovskite and Superhalogen Hybrid Perovskite.

The use of superlattice structures is an attractive strategy for expanding the family of perovskites and obtaining excellent optoelectronic materials. Mixing of cations and partial replacement of halogens by superhalogens are advantageous for improving the stability and optoelectronic properties of hybrid perovskites. Herein, the superlattice structures of the (CsPbI)/MAPbIBF, (FAPbI)/MAPbIBF, (MAPbI)/CsPbIBF, and (FAPbI)/CsPbIBF hybrid perovskites were investigated using first-principles density functional theory calculations.

Secondary Grain Growth in Organic-Inorganic Perovskite Films with Ethylamine Hydrochloride Additives for Highly Efficient Solar Cells.

The grain boundaries of perovskite polycrystalline are regarded as a defect region that not only provides carrier recombination sites but also introduces device degradation pathways. Efforts to enlarging the grain size of a perovskite film and reducing its grain boundary are crucial for highly efficient and stable perovskite solar cells (PSCs). Some effective methods that facilitate grain growth are postdeposition thermal annealing and solvent vapor annealing.

Electronic and optical absorption properties of organic-inorganic perovskites as influenced by different long-chain diamine molecules: first-principles calculations.

Organic-inorganic perovskites have demonstrated significant promise as photovoltaic materials due to their excellent photoelectric properties. However, monoamino three-dimensional (3D) perovskites, such as CHNHPbI (MAPbI) and NHCHNHPbI (FAPbI) exhibit low thermal and chemical stability, leading to low device durability. As such, we sought to address this problem by evaluating the performance of five diamino-3D perovskites with different molecule chain lengths, including NH(CH)NHPbI (EDAPbI), NH(CH)NHPbI (DPAPbI), NH(CH)NHPbI (BDAPbI), NH(CH)NHPbI (PDAPbI), and NH(CH)NHPbI (HDAPbI), as well as one monoamino-2D perovskite, (CH(CH)NH)PbI (BAPbI) using first-principles calculations.

Correction: Improved fill factor in inverted planar perovskite solar cells with zirconium acetate as the hole-and-ion-blocking layer.

Correction for 'Improved fill factor in inverted planar perovskite solar cells with zirconium acetate as the hole-and-ion-blocking layer' by Xuewen Zhang et al., Phys. Chem.

Improved fill factor in inverted planar perovskite solar cells with zirconium acetate as the hole-and-ion-blocking layer.

Planar perovskite solar cells (PSCs) have gained great interest due to their low-temperature solution preparation and simple process. In inverted planar PSCs, an additional buffer layer is usually needed on the top of the PCBM electron-transport layer (ETL) to enhance the device performance. In this work, we used a new buffer layer, zirconium acetate (Zr(Ac)).

Toward All Room-Temperature, Solution-Processed, High-Performance Planar Perovskite Solar Cells: A New Scheme of Pyridine-Promoted Perovskite Formation.

A new, all room-temperature solution process is developed to fabricate efficient, low-cost, and stable perovskite solar cells (PVSCs). The PVSCs show high efficiency of 17.10% and 14.

Efficient near-infrared light-emitting diodes based on organometallic halide perovskite-poly(2-ethyl-2-oxazoline) nanocomposite thin films.

Organometallic halide perovskites have recently drawn considerable attention for applications in light emission diodes (LEDs). However, the small exciton binding energy of the CHNHPbI perovskite has the concerns of large exciton dissociation and low radiative recombination on its use in near-infrared LEDs (NIR-LEDs). Herein, we propose and demonstrate that the introduction of poly(2-ethyl-2-oxazoline) (PEtOz) into the perovskite can simultaneously improve the recombination rate and radiative decay rate for improving perovskite LED performances.

[Raman and Visible-Near Infrared Spectra of Cu(InGa)Se2 Films].

Cu(InxGa1-x)Se2(CIGS) precursor films were prepared on ITO glass with potentiostatic electrodeposition. High quality CIGS films were obtained by selenization of the precursor films at high temperature in tubular furnace full of argon gas. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis-NIR spectroscopy were used to characterize the structure, morphology, composition and Vis-NIR absorption of CIGS films, respectively.

[Raman and Visible-Near Infrared Spectra of Cu(InGa)Se2 Films].

Cu(InxGa1-x)Se2(CIGS) precursor films were prepared on ITO glass with potentiostatic electrodeposition. High quality CIGS films were obtained by selenization of the precursor films at high temperature in tubular furnace full of argon gas. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis-NIR spectroscopy were used to characterize the structure, morphology, composition and Vis-NIR absorption of CIGS films, respectively.

Room-Temperature Solution-Processed NiOx:PbI2 Nanocomposite Structures for Realizing High-Performance Perovskite Photodetectors.

While methylammonium lead iodide (MAPbI3) with interesting properties, such as a direct band gap, high and well-balanced electron/hole mobilities, as well as long electron/hole diffusion length, is a potential candidate to become the light absorbers in photodetectors, the challenges for realizing efficient perovskite photodetectors are to suppress dark current, to increase linear dynamic range, and to achieve high specific detectivity and fast response speed. Here, we demonstrate NiOx:PbI2 nanocomposite structures, which can offer dual roles of functioning as an efficient hole extraction layer and favoring the formation of high-quality MAPbI3 to address these challenges. We introduce a room-temperature solution process to form the NiOx:PbI2 nanocomposite structures.

Electron transporting organic materials with an exceptional large scale homeotropic molecular orientation.

An electron transporting anthraquinone derivative demonstrated a stable large-scale homeotropic alignment on an open substrate surface, which substantially improved its charge carrier mobility. The electron mobility (μ(E)) increased by two orders of magnitude from 3.2 × 10(-4) cm(2) V(-1) s(-1) for the film without alignment to 1.

Dynamic interface charge governing the current-voltage hysteresis in perovskite solar cells.

The accumulation of mobile ions causes space charge at interfaces in perovskite solar cells. There is a slow dynamic process of ion redistribution when the bias is changed. The interface charge affects band bending and thus the photocurrent of the solar cells.

[Comparative study on thin films of cadmium sulfide prepared by chemical bath deposition and radio frequency magnetron sputtering].

Thin films of cadmium sulfide (CdS) were prepared with ammonium chloride, cadmium chloride, potassium hydroxide and thiourea by chemical bath deposition (CBD). For comparison, CdS films were also deposited by radio frequency (RF) magnetron sputtering, using CdS and argon as a target and reactive gas, respectively. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible spectroscopy.

[Ideal white organic light emitting devices based on doped PFO].

In the present paper, the electroluminescence emission from a doped polymer layer was studied. The blue fluorene PFO was used as the host material and MEH-PPV as the dopant. The spectral characteristics and color stability of the emission on CIE chromaticity diagram were investigated.

A mesogenic triphenylene-perylene-triphenylene triad.

A straightforward synthesis of triphenylene-perylene-triphenylene triad structures has been achieved by using versatile triphenylene intermediates bearing a single oxyalkyl amine side chain. Among these, PBITP(10) showed a stable columnar mesophase implying favorably matched core-core separations in the structure. Importantly, the triad can be used as a vehicle for doping columnar triphenylene matrices with functional but incompatible perylene units and a mixture of hexahexyloxytriphenylene matrix doped with 0.

Exploring reversible quenching of fluorescence from a pyrazolo[3,4-b]quinoline derivative by protonation.

Pyrazolo[3,4-b]quinoline derivatives are reported to be highly efficient organic fluorescent materials suitable for applications in light-emitting devices. Although their fluorescence remains stable in organic solvents or in aqueous solution even in the presence of H(2)O, halide salts (LiCl), alkali (NaOH) and weak acid (acetic acid), it suffers an efficient quenching process in the presence of protic acid (HCl) in aqueous or ethanolic solution. This quenching process is accompanied by a change in the UV spectrum, but it is reversible and can be fully recovered.

[Investigation on performance enhancement of bulk heterojunction organic solar cells].

Four organic solar cells with the different structures were fabricated. The structures are Device1 ITO/LiF/PEDOT: PSS/MEH-PPV/C60/Al, Device 2 ITO/PEDOT : PSS/MEH-PPV/C60/Al, Device 3 ITO/LiF/PEDOT : PSS/MEH-PPV : C60/C60/Al and Device 4 ITO/PEDOT : PSS/MEH-PPV : C60/C60/Al. Then we compared the current-voltage (I-V) characteristics of these devices and found that the insertion of a thin LiF layer between the ITO electrode and the PEDOT : PSS layer resulted in much improved device performance.

[Emitting characteristics and carrier composite regions variety of the blend of terbium complex and poly-n-vinylcarbazole].

A new rare earth complex TbGd(BA)6(bipy)2 was synthesized, which was used as an emitting material in electroluminescence. By doping with poly-N-vinylcarbazole (PVK), the stability and conductivity of terbium complex were improved. The photoluminescence of PVK, terbium complex and their blend indicated that energy transfer from PVK to terbium complex occurred.