Hybrid Halide Perovskites Research Articles

2D Hybrid Perovskites Employing an Organic Cation Paired with a Neutral Molecule.

Two-dimensional (2D) hybrid perovskites harness the chemical and structural versatility of organic compounds. Here, we explore 2D perovskites that incorporate both a first organic component, a primary ammonium cation, and a second neutral organic module. Through the experimental examination of 42 organic pairs with a range of functional groups and organic backbones, we identify five crystallization scenarios that occur upon mixing. Only one leads to the cointercalation of the organic modules with distinct and extended interlayer spacing, which is observed with the aid of X-ray diffraction (XRD) pattern analysis combined with cross-sectional transmission electron microscopy (TEM) and elemental analysis. We present a picture in which complementary pairs, capable of forming intermolecular bonds, cocrystallize with multiple structural arrangements. These arrangements are a function of the ratio of organic content, annealing temperature, and substrate surface characteristics. We highlight how noncovalent bonds, particularly hydrogen and halogen bonding, enable the influence over the organic sublattice in hybrid halide perovskites.

Insights into the Growth Orientation and Phase Stability of Chemical-Vapor-Deposited Two-Dimensional Hybrid Halide Perovskite Films.

Chemical vapor deposition (CVD) offers a large-area, scalable, and conformal growth of perovskite thin films without the use of solvents. Low-dimensional organic-inorganic halide perovskites, with alternating layers of organic spacer groups and inorganic perovskite layers, are promising for enhancing the stability of optoelectronic devices. Moreover, their multiple quantum-well structures provide a powerful platform for tuning excitonic physics. In this work, we show that the CVD process is conducive to the growth of 2D hybrid halide perovskite films. Using butylammonium (BA) and phenylethylammonium (PEA) cations, the growth parameters of BA2PbI4 and PEA2PbI4 and mixed halide perovskite films were first optimized. These films are characterized by well-defined grain boundaries and display characteristic absorption and emission features of the 2D quantum wells. X-ray diffraction (XRD) and a noninteger dimensionality model of the absorption spectrum provide insights into the orientation of the crystalline planes. Unlike BA2PbI4, temperature-dependent photoluminescence measurements from PEA2PbI4 show a single excitonic peak throughout the temperature range from 20 to 350 K, highlighting the lack of defect states. These results further corroborate the temperature-dependent synchrotron-based XRD results. Furthermore, the nonlinear optical properties of the CVD-grown perovskite films are investigated, and a high third harmonic generation efficiency is observed.

Self-powered solution-processed photodetectors utilizing FAPbBr3:C60 bulk heterojunction

Hybrid halide perovskites have emerged as pivotal optoelectronic materials due to their easy and cost-effective solution-based manufacturing processes. In this study, we have combined formamidinium lead bromide (FAPbBr3) with buckminsterfullerene (C60) to create the bulk heterojunction (BHJ) photoactive layer for solution-processed photodetectors. Remarkably, the FAPbBr3:C60 BHJ-based photodetectors exhibited a substantial enhancement in optoelectronic performance, with the responsivity increasing from 0.87 A/W to 1.47 A/W compared to the pristine FAPbBr3. This improvement can be attributed to the superior surface morphology and crystallinity of the FAPbBr3:C60 BHJ thin film, which facilitated enhanced charge transport properties. Furthermore, the fabricated photodetectors demonstrated remarkable detectivity even at 0V, enabling self-powered operation. By employing the space charge limited conduction (SCLC) model, we were able to elucidate the dominant charge transport mechanism. At lower voltages, trap-free SCLC was identified as the primary mechanism, while traps governed charge transport at higher voltages. Additionally, we conducted impedance analysis to investigate the underlying factors contributing to the distinctive optoelectronic performance observed in the photodetectors.

Research and Optimization of Crystallization Processes of Solutions of Hybrid Halide Perovskites of the CH3NH3PbI3 Composition

Research and Optimization of Crystallization Processes of Solutions of Hybrid Halide Perovskites of the CH3NH3PbI3 Composition

Host–Guest Complexation in Wide Bandgap Perovskite Solar Cells

Wide‐bandgap hybrid halide perovskites are increasingly relevant in the fabrication of tandem solar cells. However, their efficiency and stability during operation are still limited by several factors, among which ion migration at the interface with charge‐selective extraction layers is one of the most detrimental ones. Herein, a host–guest complexation strategy is employed to control interfacial ion migration by using dibenzo‐21‐crown‐7 in wide‐bandgap hybrid halide perovskites based on methylammonium lead bromide. The capacity of the crown ether is demonstrated that affect the performances and stabilities of MAPbBr3 solar cells. As a result, power conversion efficiencies of up to 5.9% are achieved with an open circuit voltage as high as 1.5 V, which is accompanied by stability over 300 h at 85 °C under nitrogen atmosphere, as well as more than 300 h at ambient temperature, maintaining ∼80% of initial performance. This provides a versatile strategy for wide‐bandgap photovoltaic devices.

Iontronics in Hybrid Halide Perovskites for Smart Portable Electronic Devices and Their Challenges

Iontronics in Hybrid Halide Perovskites for Smart Portable Electronic Devices and Their Challenges

Surface defect passivation by copper incorporation for efficient perovskite solar cells

Defects play an important character in the degradation processes of hybrid halide perovskite, hindering their application for solar cells. Ion transport is facilitated by the ubiquitous organic cation and halide anion vacancy defects, which lead to perovskite disintegration at grain boundaries. In this article, a thorough investigation of the vacancy defect and defect density on perovskite is conducted by using VASP and SCAPS-1D. From SCAPS-1D, the PCE of the device increases from 17.82 % to 23.04 % when the defect state density drops from 10+15 to 10+14 cm-3. Therefore, reducing the defect density is very important to improve the performance of perovskite solar cells. Effective perovskite solar cells based on CH3NH3PbI3 incorporated copper ions passivation defects were carried out. Compare to pristine hybrid perovskite, Cu2+-doped hybrid perovskite have remarkably lower trap-state densities, greater film quality, and higher crystallinity. Especially, the maximum power conversion efficiency of up to 20.1 % was achieved with 0.5 % copper ion doping. After 500 h of not being enclosed in dry air, the devices still has 87 % of its original power conversion efficiency. Therefore, this work suggests that careful control the formation of Cu2+ in perovskite films is very important for diverse optoelectronic applications in the future.

Chiral-Achiral Cations Intercalation Induced Lead-Free Chiral-Polar Hybrid Perovskites Enable Self-Powered X-Ray and Ultraviolet-Visible-Near-Infrared Photo Detection.

Lead halide hybrid perovskites have made great progress in direct X-ray detection and broadband photodetection, but the existence of toxic Pb and the demand for external operating voltage have severely limited their further applications and operational stability improvements. Therefore, exploring "green" lead-free hybrid perovskite that can both achieve X-ray detection and broadband photodetection without external voltage is of great importance, but remains severely challenging. Herein, using centrosymmetric (BZA)3BiI6 (1, BZA = benzylamine) as a template, a pair of chiral-polar lead-free perovskites, (BZA)2(R/S-PPA)BiI6 (2-R/S, R/S-PPA = (R/S)-1-Phenylpropylamine) are successfully obtained by introducing chiral aryl cations of (R/S)-1-Phenylpropylamine. Compared to 1, chiral-polar 2-R presents a significant irradiation-responsive bulk photovoltaic effect (BPVE) with an open circuit photovoltage of 0.4V, which enables it with self-powered X-ray, UV-vis-NIR broadband photodetection. Specifically, 2-R device exhibits an ultralow detection limit of 18.5nGys-1 and excellent operational stability. Furthermore, 2-R as the first lead-free perovskite achieves significant broad-spectrum (377-940nm) photodetection via light-induced pyroelectric effect. This work sheds light on the rational crystal reconstruction engineering and design of "green" hybrid perovskite toward high-demanded self-powered radiation detection and broadband photodetection.

Improving the Conductivity of Amide-Based Small Molecules through Enhanced Molecular Packing and Their Application as Hole Transport Mediators in Perovskite Solar Cells.

Organic-inorganic hybrid halide perovskite solar cells (PSCs) have attracted substantial attention from the photovoltaic research community, with the power conversion efficiency (PCE) already exceeding 26%. Current state-of-the-art devices rely on Spiro-OMeTAD as the hole-transporting material (HTM); however, Spiro-OMeTAD is costly due to its complicated synthesis and expensive product purification, while its low conductivity ultimately limits the achievable device efficiency. In this work, we build upon our recently introduced family of low-cost amide-based small molecules and introduce a molecule (termed TPABT) that results in high conductivity values (∼10-5 S cm-1 upon addition of standard ionic additives), outperforming our previous amide-based material (EDOT-Amide-TPA, ∼10-6 S cm-1) while only costing an estimated $5/g. We ascribe the increased optoelectronic properties to favorable molecular packing, as shown by single-crystal X-ray diffraction, which results in close spacing between the triphenylamine blocks. This, in turn, results in a short hole-hopping distance between molecules and therefore good mobility and conductivity. In addition, TPABT exhibits a higher bandgap and is as a result more transparent in the visible range of the solar spectrum, leading to lower parasitic absorption losses than Spiro-OMeTAD, and has increased moisture stability. We applied the molecule in perovskite solar cells and obtained good efficiency values in the ∼15% range. Our approach shows that engineering better molecular packing may be the key to developing high-efficiency, low-cost HTMs for perovskite solar cells.

The influence of different metals (II) in hybrid perovskite of (2-AMP)BI4 (B = Pb, Sn) onto the structural, electronic and optical properties: A DFT study

The first principle study on structural, electronic, and optical properties of 2D hybrid halide compound (2-AMP)BI4 (B = Pb, Sn) was analyzed using CASTEP computer code. The calculations were performed using generalized gradient approximation (GGA) schemes. This study aims to look at a few characteristics of (2-AMP)SnI4 as a potential replacement for (2-AMP)PbI4 as a light absorber in solar cell applications due to its toxicity to humans and the environment. The results show that the substitution of lead (Pb) with tin (Sn) can replace Pb-based hybrid halide perovskite due to low band gap, high optical absorption in UV–Visible area, and improved polarizability of electric current. To conclude, 2D Sn-based solar cells are well suited for light harvesting in solar devices. This research may give some information on the properties of 2D Sn-based solar cells for use in renewable energy applications.

A Two-Dimensional Hybrid Perovskite With Heat Switching Birefringence.

Birefringent crystals that can switch light polarization have important applications in optoelectronics. In the last decades, birefringence is mostly optimizedby chemical strategies. Recently, switching birefringence by physical means has attracted much attention. Here, this work reports the observation of heat switching birefringence in a 2D layered hybrid halide perovskite (C2N3H4)2PbCl4 ([C2N3H4]+ = 1,2,4-triazolium). This heat switching birefringence leads to a significant change in the interference color for the crystal plate under the illumination of orthogonal polarized light. Structure analyses reveal a heat dependent structure transition in (C2N3H4)2PbCl4, whose birefringence is switched by the change in the distortion degree of PbCl6 octahedron. This discovery may be beneficial to the further development of stimuli-responsive polarization optical devices.

A Two‐Dimensional Hybrid Perovskite With Heat Switching Birefringence

AbstractBirefringent crystals that can switch light polarization have important applications in optoelectronics. In the last decades, birefringence is mostly optimized by chemical strategies. Recently, switching birefringence by physical means has attracted much attention. Here, this work reports the observation of heat switching birefringence in a 2D layered hybrid halide perovskite (C2N3H4)2PbCl4 ((C2N3H4)+=1,2,4‐triazolium). This heat switching birefringence leads to a significant change in the interference color for the crystal plate under the illumination of orthogonal polarized light. Structure analyses reveal a heat dependent structure transition in (C2N3H4)2PbCl4, whose birefringence is switched by the change in the distortion degree of PbCl6 octahedron. This discovery may be beneficial to the further development of stimuli‐responsive polarization optical devices.

Optimized High-Efficiency Solar Cells with Dual Hybrid Halide Perovskite Absorber Layers

Optimized High-Efficiency Solar Cells with Dual Hybrid Halide Perovskite Absorber Layers

Computation of the Dielectric and Optical Properties of Dimethylammonium Tin Triiodostanate (II) Perovskite for Solar Cell Application

Hybrid halide perovskites are promising photovoltaic materials for use in solar cells. The ongoing research on perovskites have shown that these materials are potential light-harvesting mediums. The optical properties of dimethylammonium triiodostanate (II) (DASnI3) a hybrid halide perovskites needs to be studied because it can be a good light absorber material due to the wide band gap exhibited. The real and the imaginary parts of the dielectric is a measure of the extent of light absorption. The GGA+U exchange-correlation implemented in Quantum ESPRESSO was used basing on density functional theory to obtain the optical properties. The DASnI3 has a direct band gap of 2.7 eV with the real part of the dielectric diagram indicating that the maximum value of ε1 (ω) is in the visible range of (3.0–3.5 eV). High absorption peaks were also observed in the visible spectral region at energy of around (3.5–4.5 eV) with several weak peaks observed in the energy range of (4.5–14.0 eV). The band structure and the dielectric functions are important in the study of optical properties. These properties expresses the interaction of light with the material medium and thus the luminescence of the device which are important in the use of DASnI3 as a solar cell material in photovoltaics.

Perovskite-Solar-Cell-Powered Integrated Fuel Conversion and Energy-Storage Devices.

Metal halide hybrid perovskite solar cells (PSCs) have received considerable attention over the past decade owing to their potential for low-cost, solution-processable, earth-abundant, and high-performance superiority, increasing power conversion efficiencies of up to 25.7%. Solar energy conversion into electricity is highly efficient and sustainable, but direct utilization, storage, and poor energy diversity are difficult to achieve, resulting in a potential waste of resources. Considering its convenience and feasibility, converting solar energy into chemical fuels is regarded as a promising pathway for boosting energy diversity and expanding its utilization. In addition, the energy conversion-storage integrated system can efficiently sequentially capture, convert, and store energy in electrochemical energy storage devices. However, a comprehensive overview focusing on PSC-self-driven integrated devices with a discussion of their development and limitations remains lacking. Here, focus is on the development of representative configurations of emerging PSC-based photo-electrochemical devices including self-charging power packs, unassisted solar water splitting/CO2 reduction. The advanced progresses in this field, including configuration design, key parameters, working principles, integration strategies, electrode materials, and their performance evaluations are also summarized. Finally, scientific challenges and future perspectives for ongoing research in this field are presented.

A first‐principles investigation into the rational design of Sn‐halide perovskite materials as an alternative to Pb‐based perovskites

AbstractThe development of Pb‐free alternatives for perovskite‐based photovoltaics is extremely important due to the toxicity of Pb to the environment. Sn‐based organic inorganic hybrid halide perovskites are considered to be the most suitable alternative to Pb‐based ABX perovskites due to their similar optoelectronic properties. The selection of A site cation in ABX type perovskites is crucial for favorable structural and mechanical properties. Using first principle methods, we have designed and investigated Sn–I based hybrid halide perovskite materials with different organic cations mixed in equal proportions. Observed tolerance (TF) and octahedral factors () indicate the formation of stable three‐dimensional perovskite structure. Our studied materials also exhibit thermodynamic stability due to the negative value of their formation energies. Observed band gap values indicate the semiconducting nature of our studied perovskite materials. Calculated optical properties indicate that all of the compounds exhibit suitable dielectric functions and absorption coefficients in the visible range of the electromagnetic spectrum. The observed highest value of theoretical power conversion efficiency of MA‐AMSnI (11.24%) indicates its potential to be used in photovoltaics. Our investigation will be beneficial for researchers to develop less toxic and efficient perovskite materials for the fabrication of optoelectronic devices.

Efficient and stable Sn based perovskite solar cells by the modulation of crystallization with bulky organic cation for large nucleation cluster

Organic-inorganic hybrid halide perovskite have been attracting much attention as promising photovoltaic materials owing to their exceptional photovoltaic characteristics. However, even though the rise of progress for the perovskite solar cell was increased, it was still remained the concern for the toxicity of lead in hybrid organolead based perovskite solar cell, which is the harmful materials to the environmental system.Herein, we incorpoarted the homopiperazium (HP2+) into the FASnI3 perovskite to prepare a high-quality perovskite film with a lower defect density. Since the HP is the largest organic cation, that can not enter 3D perovskite but it played a significant role in modulating the crystallinity, morphology and optoelectronic properties of FASnI3 perovskite. When the HPI2 introduced the perovskite precursor solution, it affects the nucleation of perovskite solution by the formation of large pre-nulceation cluster through the linked colloids. It decrease the energy barrier, resulting in a high-quality perovskite film with a lower defect density. Highly oriented perovskite film exhibits the PCE up to a high at 6.88%, with high long-term stability as well which is much higher than that of the pristine FASnI3 perovskite film (4.71%).

Enhancing perovskite solar cells efficiency via bulk passivation of light absorbing material with L-cysteine hydrochloride

L-Cysteine hydrochloride (CysCl) has been found to be an effective additive to hybrid halide perovskites, improving both the quality of perovskite films and the operando parameters of perovskite solar cells. The origin of the CysCl effect on the mixed-cation hybrid halide perovskite and related photovoltaic devices has been disclosed.

A polarization-dependent near-infrared metamaterial absorber based on the hybrid halide perovskite in two orthogonal directions

A wide-angle and polarization-sensitive metamaterial absorber is highly desired for near-infrared optical applications, such as stealth coatings, photovoltaic materials, and detectors. Although current near-infrared metamaterial absorbers achieve high absorption rates, they are typically either polarization-independent or only sensitive to one direction. Herein, a (CH3NH3)PbBr3-based perfect absorber with high absorption in both orthogonal directions and polarization sensitivity has been designed. The maximum absorption in the transverse magnetic (TM)-polarized light exceeds 99.6% at 800–1000 nm. The maximum absorption in the transverse electric (TE)-polarized light exceeds 98.9% at 1500–1800 nm, and the peak absorption is more than 84.3% at 1800–2200 nm using finite-difference time-domain methods. By modifying various structural parameters, the absorption of the absorber could be separately shifted in a wide wavelength region. In addition, the designed absorber maintains good performance at large angles of incidence. This structure can be applied to other hybrid perovskite materials by simply changing the structural parameters. These results present a huge potential for applications based on metamaterial absorbers, such as infrared polarization imaging, selective spectral detection, near-infrared sensing, and polarization multiplexing.

Broad-range high-resolution optical spectroscopy of CH3NH3PbBr3 hybrid perovskite single crystals: Optical phonons, absorption edge, phase transitions

Vibrational and structural properties have an enormous influence on optoelectronic properties of hybrid halide perovskites CH3NH3PbX3 (X = I, Br, Cl), which are perspective materials for different photovoltaic applications. Here, we report results of the first high-resolution optical spectroscopy measurements of large CH3NH3PbBr3 single crystals in wide frequency (20–20 000 cm−1) and temperature (5–300 K) ranges. Fit of polarized far-infrared reflection spectra using Lorentz model of damped oscillators revealed parameters of three phonons at room temperature and 38 phonons at 10 K. An analysis of mid-infrared transmission spectra gave evidence of a strong anharmonicity in this hybrid perovskite. A splitting of some lines observed in the orthorhombic phase was presumably assigned to the tunneling of the CH3NH3+ cation molecule between several potential energy minima. The temperature behavior of the transmission spectra near the fundamental absorption edge was tentatively explained by the competition between two different exciton transitions in CH3NH3PbBr3. Positions of spectral lines and of the absorption edge measured at cooling and heating the sample demonstrate hysteresis loops in the vicinities of phase transitions around 237, 155, and 149 K, thus revealing the first-order nature of all three phase transitions in CH3NH3PbBr3.