Organic-inorganic Hybrid Perovskite Research Articles

The effect of organic ligand length on structural, vibrational and electrical properties of low-dimensional cobalt hybrid perovskites

Recently, two-dimensional hybrid organic–inorganic perovskites (2D-HOIPs) have emerged in popularity due to ease of tunability in terms of the structure and properties. However, a systematic chemistry and physical description of cobalt-based system is lacking. In this study, we employ X-ray diffraction, Raman spectroscopy and electrochemical impedance spectroscopy (EIS) techniques to investigate the effect of the organic ligand length on the structural, vibrational, and electrical properties of A2CoCl4 [A = methylammonium (MA), ethylammonium (EA) and butylammonium (BA)] perovskite. Results from the measurements showed a noticeable difference and showed potential usage in future applications in the field of electronics.

Performance analysis of A3B2X9 (Cs3Bi2I9) based perovskite photovoltaic tandem structure with crystalline Silicon (c-Si)

The efficiency of solar cells with single-junction utilizing organic-inorganic hybrid perovskites have attained a value more than 25.5%. The device power conversion efficiency (PCE) can be improved further either by optimizing the absorber layer (Perovskite film) or by investigating the novel device structures such as tandem based solar cells with perovskite and silicon. This combination of top cell (Perovskite solar cell) and bottom cell (Silicon solar cell) can improve the PCE which surpasses the Shockley-Queisser limit of single-junction solar cells by utilizing a wider range of solar spectrum. This paper presents an optimization and simulation of standalone Cs3Bi2I9 perovskite solar cell which was later integrated with a c-Si solar cell to simulate a tandem structure using SCAPS-1D software. The aim is to investigate the performance enhancement of the perovskite solar cell by optimizing it and stacking it on top of a high-efficiency c-Si solar cell using a four-terminal (4T) structure. At a short-circuit current density of 16.165 mA/cm2 and an open-circuit voltage of 1.41 V, the simulation findings demonstrate that the Cs3Bi2I9 perovskite solar cell exhibits a high-power conversion efficiency of 20.37%. The tandem structure demonstrates an enhanced power conversion efficiency of 31.59% which is significantly higher than the efficiency of the individual cells. The Cs3Bi2I9 perovskite solar cell is a great choice for application in tandem systems with c-Si solar cells for high-efficiency, according to the simulation results. This study provides valuable insights for the development of efficient perovskite/c-Si tandem solar cells.

Bulk and interface passivation through potassium iodide additives engineering enables high-performance and humidity-stable CsPbBr3 perovskite solar cells

Organic-inorganic hybrid perovskite solar cells (PSCs) have gained significant attention in the past decade due to their exceptional photovoltaic performance and unique advantages. However, the organic cation component of the hybrid perovskites results in poor humidity resistibility and thermal stability. Replacing organic cations with inorganic cations, such as Cs+, to fabricate all-inorganic CsPbX3 PSCs, is an effective way to improve their stability. Among the CsPbX3 PSCs, full-brominated CsPbBr3 PSCs have excellent moisture and thermal tolerance, with great potential for commercialization. However, these PSCs suffer from energy loss during operation, and their photoelectric conversion efficiency is lower than that of mainstream hybrid PSCs. Additive engineering is an effective method to improve the quality of perovskite films, which introduces functional additives into the perovskite precursor to induce perovskite crystallization, achieve the passivation of uncoordinated ions defects, and finely tune the energy level structures. In this study, Potassium iodide (KI) was added to the CsBr precursor solution to participate in the formation of the CsPbBr3 perovskite thin film. The partial substitution of A-site cation in the ABX3 perovskite occurred during the film formation, leading to beneficial variation of the crystal structure and photoelectronic performance in the CsPbBr3 system. The planar-architecture device based on the modified CsPbBr3 layer could reach a best efficiency of 10.06 %, together with a high open-circuit voltage (Voc) of 1.60 V. The KI-doped CsPbBr3 based PSC can retain over 90 % of the original PCE even after 30 days of aging, thanks to the diminished defect density by the KI passivation.

The dopant-free hole transport material based on benzo[1,2-b:4,5-b']dithiophene with high efficiency in inverted perovskite solar cells

In the commercialization process of organic-inorganic hybrid perovskite solar cells (OIH–PSCs), the research of dopant-free hole transport materials (HTMs) with high efficiency is still an urgent problem. In this work, we synthesize two organic small molecule HTMs with well-known benzodithiophene (BDT) as the central unit, abbreviated as BDTO-MTP and BDTT-PMTP. Compared with BDTO-MTP (with oxygen-substituted alkyl chain and diphenylamine derivatives as the terminal group), BDTT-PMTP introduces thiophene to replace oxygen beside the central group, triphenylamine to replace diphenylamine derivatives as the terminal group. Both BDTO-MTP and BDTT-PMTP exhibit high hole mobility without doping. It is worth noting that two new materials are introduced into inverted OIH-PSCs as a doped-free hole transport layer, the champion efficiency of MAPbI3-based devices based on BDTT-PMTP reaches 21.08%, and the highest efficiency of BDTO-MTP-based devices can also reach 19.54%. The results show that the planar building blocks with the similarity of BDT will be an excellent and universal choice for the future design of dopant-free small molecule HTMs with high efficiency.

Realizing Stable Perovskite Solar Cells with Efficiency Exceeding 25.6% Through Crystallization Kinetics and Spatial Orientation Regulation.

Organic-inorganic hybrid perovskites have emerged as highly promising candidates for photovoltaic applications, owing to the exceptional optoelectronic properties and low cost. Nonetheless, the performance and stability of solar cells suffer from the defect states of perovskite films aroused by non-optically active phases and non-centralized crystal orientation. Herein, a versatile organic molecule, Hydantoin, to modulate the crystallization of perovskite, is developed. Benefiting from the diverse functional groups, more spatially oriented perovskite films with high crystallinity are formed. This enhancement is accompanied by a conspicuous reduction in defect density, yielding efficiency of 25.66% (certified 25.15%), with superb environmental stability. Notably, under the standard measurement conditions (ISOS-L-1I), the maximum power point (MPP) output maintains 96.8% of the initial efficiency for 1600 h and exhibits excellent ion migration suppression. The synergistic regulation of crystallization and spatial orientation offers novel avenues for propelling perovskite solar cell (PSC) development.

Temperature dependence of iodine vacancies concentration in [formula omitted] perovskite: A theoretical analysis

In this study, we investigate the temperature dependence of iodine vacancies in the organic-inorganic hybrid perovskite CH3NH3PbI3 through theoretical analysis. Iodine vacancies, as point defects, play a crucial role in the instability of perovskite solar cells. By employing molecular dynamics (MD) simulations, we calculate the formation energy of vacancies and examine its relationship with temperature. Our results reveal that the formation energy remains constant irrespective of temperature. However, elevated temperatures facilitate the provision of energy necessary for vacancy formation. To accurately determine the vacancy concentration, it is essential to consider the associated entropy changes. Analytical methods are employed to assess these entropy changes, offering valuable insights into the vacancy formation process. Utilizing the derived values, we quantify the concentration of vacancies and analyze their dependence on temperature. The findings obtained from this research contribute significant insights into the behavior of iodine vacancies within the studied CH3NH3PbI3 perovskite system.

BMP]+[BF4]--Modified CsPbI1.2Br1.8 Solar Cells with Improved Efficiency and Suppressed Photoinduced Phase Segregation.

With the rapid progress in a power conversion efficiency reaching up to 26.1%, which is among the highest efficiency for single-junction solar cells, organic-inorganic hybrid perovskite solar cells have become a research focus in photovoltaic technology all over the world, while the instability of these perovskite solar cells, due to the decomposition of its unstable organic components, has restricted the development of all-inorganic perovskite solar cells. In recent years, Br-mixed halogen all-inorganic perovskites (CsPbI3-xBrx) have aroused great interests due to their ability to balance the band gap and phase stability of pure CsPbX3. However, the photoinduced phase segregation in lead mixed halide perovskites is still a big burden on their practical industrial production and commercialization. Here, we demonstrate inhibited photoinduced phase segregation all-inorganic CsPbI1.2Br1.8 films and their corresponding perovskite solar cells by incorporating a 1-butyl-1-methylpiperidinium tetrafluoroborate ([BMP]+[BF4]-) compound into the CsPbI1.2Br1.8 films. Then, its effect on the perovskite films and the corresponding hole transport layer-free CsPbI1.2Br1.8 solar cells with carbon electrodes under light is investigated. With a prolonged time added to the reduced phase segregation terminal, this additive shows an inhibitory effect on the photoinduced phase segregation phenomenon for perovskite films and devices with enhanced cell efficiency. Our study reveals an efficient and simple route that suppresses photoinduced phase segregation in cesium lead mixed halide perovskite solar cells with enhanced efficiency.

Structure-Guided Approaches for Enhanced Spin-Splitting in Chiral Perovskite.

Hybrid organic-inorganic perovskites with diverse lattice structures and chemical composition provide an ideal material platform for novel functionalization, including chirality transfer. Chiral perovskites combine organic and inorganic sublattices, therefore encoding the structural asymmetry into the electronic structures and giving rise to the spin-splitting effect. From a structural chemistry perspective, the magnitude of the spin-splitting effect crucially depends on the noncovalent and electrostatic interaction within the chiral perovskite, which induces the local site and long-range bulk inversion symmetry breaking. In this regard, we systematically retrospect the structure-property relationships in chiral perovskite. Insight into the rational design of chiral perovskites based on molecular configuration, dimensionality, and chemical composition along with their effects on spin-splitting manifestation is presented. Lastly, challenges in purposeful material design and further integration into chiral perovskite-based spintronic devices are outlined. With an understanding of fundamental chemistry and physics, we believe that this Perspective will propel the application of multifunctional spintronic devices.

Perovskite-Supramolecular Co-Assembly for Chiral Optoelectronics.

Hybrid inorganic-organic perovskites with chiral response and outstanding optoelectronic characteristics are promising materials for next-generation spin-optoelectronics. In particular, two-dimensional (2D) perovskites are promising chiroptical candidates due to their unique ability to incorporate chiral organic cations into their crystal structure, which imparts chirality. To enable their practical applications in chiral optoelectronic devices, it is essential to achieve an anisotropy factor (gCD ∼ 2) in chiral 2D perovskites. Currently, chiral 2D perovskites exhibit a relatively low gCD of 3.1 × 10-3. Several approaches have been explored to improve the chiral response of chiral 2D perovskites, including tailoring the molecular structure of chiral cations and increasing the degree of octahedral tilting in the perovskite lattice. However, current methods for chiral amplification have only achieved a moderate enhancement of gCD by 2-fold and are often accompanied by undesirable shifts or inversion in the circular dichroism spectra. There is a need for a more efficient approach to enhancing the chirality in 2D perovskites. Here, we report an innovative coassembly process that allows us to seamlessly grow chiral 2D perovskites on supramolecular helical structures. We discover that the interactions between perovskites and chiral supramolecular structures promote crystal lattice distortion in perovskites, which improves the chirality of 2D perovskites. Additionally, the obtained hierarchical coassembly can effectively harness the structural chirality of the supramolecular helices. The multilevel chiral enhancement leads to an enhancement in gCD by 2.7-fold without compromising the circular dichroism spectra of 2D perovskites.

Temperature- and illumination-dependent recombination of the photoinduced charge carriers in organic–inorganic hybrid perovskite solar cells

Temperature- and illumination-dependent recombination of the photoinduced charge carriers in organic–inorganic hybrid perovskite solar cells

Unconventional perovskite-to-perovskite tandem cell designed by stacking with large-gap phosphonium-based analogs

We present a material design strategy for stacking large-gap unconventional derivatives on the prevailing hybrid organic–inorganic perovskites, (MA, FA)(Sn, Pb)I3 as a perovskite-to-perovskite tandem cell. To this end, we employ an unconventional structurally well-matched hybrid organic–inorganic perovskite derivative MPSnBr3 with large-sized weakly hybridized A-site methylphosphonium (MP) cations to construct a heterojunction with its structural analogs (MA, FA)(Sn, Pb)I3 to simulate the two subcells of the tandem cell. Compared with the popular ammonium-based perovskites, density-functional theory computation suggests that MPSnBr3 possesses a wider bandgap and lower conduction band minimum level induced by the weak-hybrid MP cations, which can be a more suitable wide-range light absorber than its traditional ammonium counterparts. We show that such a heterostructure exhibits a desirable positive “spike-like’ band offset, resulting in higher Voc and more effective suppression of undesirable carrier recombination. Hence, MPSnBr3 as a structural well-matched absorber can potentially serve as the wide-range subcell in perovskite tandem cell devices.

Fine optimized cation immobilization strategy for enhancing stability and efficiency of perovskite solar cells

The migration and volatilization of cations within organic–inorganic hybrid perovskite (OIPs) materials has been identified as a major issue for irreversibly degrading perovskite solar cells (PSCs), severely limiting their performance and impeding progress toward large-scale applications. To mitigate these problems, an adjustable cation immobilization strategy was proposed for the first time, in which a series of fluorobenzenesulfonamide (FBSA) molecules was introduced into perovskite precursor, a strong coordination bond was formed between the sulfonamide group with the octahedral imperfection caused by iodine vacancy, along with a hydrogen bond formed between the cation and F atom. As a result, the A-site cations were tightly immobilized in the octahedral of perovskite crystal lattice and the uncoordinated Pb2+ defects were effectively eliminated. Besides, the immobilization distance of cation was finely optimized by changing the substitution position of F atoms. Based on the cation-immobilized perovskite film, the efficiency of PSCs was significantly increased from 19.88 % to 22.30 %. Moreover, the unencapsulated PSCs exhibited impressive light and thermal stability, retaining 82 % of the initial efficiency after 720 h illumination at 1-sun, and maintaining nearly 80 % of the initial PCE after heating at 85 °C for 240 h. Thus, the present study offers a promising approach for advancing the commercialization of stable and high-efficiency perovskite solar cells.

Revealing the stability origins of 596 days-humidity-stable semitransparent perovskite solar cells

Hybrid organic–inorganic perovskites (HOIPs) hold promise in the field of optoelectronics due to their excellent photoelectric conversion efficiency. However, the ion migration and hygroscopicity of these perovskite solar cells need to be addressed. Here, we presented semitransparent perovskite solar cells (ST-PSCs) using hole transport layer (HTL) combined with polyaniline (PANI) to stabilize HTL/perovskite interface, achieving a humidity durability (RH, 50%–90%) for 596 days (14304 h) without encapsulation. Moreover, the decrease in hydrolysis products (LiF) showed the interaction between PANI with the additives in HTL dramatically inhibited the water uptake and corrosion on MAPbI3 layer. The PANI modified samples had a higher I/Pb ratio and lower trap state density, which indicated the passivation effect of PANI on the uncoordinated Pb2+ and iodine vacancies. Subsequently, PANI successfully stabilized the interface and perovskite by inhibiting the formation of Pb0 and Au migration as long period storage. This work presented an interfacial design to develop HOIP in air with high humidity stability.

Enhancing the efficiency of the organic-inorganic hybrid perovskite cells using Al-doped ZnO as an Electron Transport Layer and CNTs as a Hole Transport Layer: An experimental and numerical study

Perovskite solar cells (PSCs) have become the subject of much discussion in the photovoltaic field due to their excellent performance over the past few years. This study presents the production, characterization, and simulation of Al-doped ZnO (AZO) as an electron transport layer (ETL) at a concentration of 1% in organic-inorganic hybrid perovskite solar cells (PSC). We experimentally elaborate the AZO thin films using the sol-gel dip-coating method. We further examined the resulting film for structural, morphological, and optical properties for use in solar cells (SCs), using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and UV–visible spectroscopy. Furthermore, this work presents an optimization process led by simulation that generates high performance using CNTs, CH3NH3PbI3, and AZO as a hole transport layer (HTL), absorber layer, and ETL respectively in solar cells using SCAPS 1D software. We have carefully examined the impact of several parameters, including the layer thicknesses, temperature, defect density of the absorber layer, defect density at interfaces between AZO and perovskite and perovskite and CNTs, and series and shunt resistances (Rs and Rsh). An optimized PSC of ITO/AZO/MAPbI3/CNTs/Au is designed here with an efficiency of 25.62%, open-circuit voltage (Voc) of 1.3955 V, fill factor (FF) of 72.32%, and current density (Jsc) of 25.382 mA/cm2. Our findings provide a remarkable efficiency using the proposed model; nevertheless, as researchers, we still need to simulate and conduct experiments to increase the cell's efficiency to potentially use it in solar cells(SCs).

Efficient Circularly Polarized Luminescence and Bright White Emission from Hybrid Indium‐Based Perovskites via Achiral Building Blocks

AbstractChiral organic‐inorganic hybrid perovskites (OIHPs) exhibit exceptional optical and chiral properties, demonstrating potential for 3D display, circularly polarized light‐emitting diodes (CP‐LEDs), and CPL switches. However, the construction of chiral OIHPs often relies on chiral building blocks, limiting chemical diversity, and possessing challenges in achieving large asymmetry factor (glum) without sacrificing photoluminescence quantum yield (PLQY). Here, Chiral DMA4In1‐xSbxCl7 (DMA = dimethylammonium, x = 0 to 1) with superior circularly polarized luminescence (CPL) are successfully constructed based on achiral building blocks DMA+ and metal halides. By optimizing the Sb3+ content, bright white emission with a high PLQY of 69.13% is achieved, as well as near‐unity PLQY yellow emission and strong CPL signals with a glum of up to +1.40 × 10−2, exhibiting a performance comparable to state‐of‐the‐art chiral OIHPs. Combining optical characterizations and theoretical calculations reveal that these intriguing properties originate from the intrinsic chiral helical structures and a pair of perfect complementary color emissions in DMA4In1‐xSbxCl7. In addition, DMA4In1‐xSbxCl7 exhibit excellent thermal stability and mild thermal quenching in the temperature range of 300 to 420 K. These fascinating properties suggest that DMA4In1‐xSbxCl7 have significant applications in white light‐emitting diodes (WLED), 3D displays and anti‐counterfeiting.

The first demonstration of entirely roll-to-roll fabricated perovskite solar cell modules under ambient room conditions

The rapid development of organic-inorganic hybrid perovskite solar cells has resulted in laboratory-scale devices having power conversion efficiencies that are competitive with commercialised technologies. However, hybrid perovskite solar cells are yet to make an impact beyond the research community, with translation to large-area devices fabricated by industry-relevant manufacturing methods remaining a critical challenge. Here we report the first demonstration of hybrid perovskite solar cell modules, comprising serially-interconnected cells, produced entirely using industrial roll-to-roll printing tools under ambient room conditions. As part of this development, costly vacuum-deposited metal electrodes are replaced with printed carbon electrodes. A high-throughput experiment involving the analysis of batches of 1600 cells produced using 20 parameter combinations enabled rapid optimisation over a large parameter space. The optimised roll-to-roll fabricated hybrid perovskite solar cells show power conversion efficiencies of up to 15.5% for individual small-area cells and 11.0% for serially-interconnected cells in large-area modules. Based on the devices produced in this work, a cost of ~0.7 USD W−1 is predicted for a production rate of 1,000,000 m² per year in Australia, with potential for further significant cost reductions.

Elucidating the Non-Covalent Interactions that Trigger Interdigitation in Lead-Halide Layered Hybrid Perovskites.

Two-dimensional (2D) hybrid organic-inorganic perovskites constitute a versatile class of materials applied to a variety of optoelectronic devices. These materials are composed of alternating layers of inorganic lead halide octahedra and organic ammonium cations. Most perovskite research studies so far have focused on organic sublattices based on phenethylammonium and alkylammonium cations, which are packed by van der Waals cohesive forces. Here, we report a more complex organic sublattice containing benzotriazole-based ammonium cations packed through interdigitated π-π stacking and hydrogen bonding. Single crystals and thin films of four perovskite derivatives are studied in depth with optical spectroscopy and X-ray diffraction, supported by density-functional theory calculations. We quantify the lattice stabilization of interdigitation, dipole-dipole interactions, and inter- as well as intramolecular hydrogen bonding. Furthermore, we investigate the driving force behind interdigitation by defining a steric occupancy factor σ and tuning the composition of the organic and inorganic sublattice. We relate the phenomenon of interdigitation to the available lattice space and to weakened hydrogen bonding to the inorganic octahedra. Finally, we find that the stabilizing interactions in the organic sublattice slightly improve the thermal stability of the perovskite. This work sheds light on the design rules and structure-property relationships of 2D layered hybrid perovskites.

Coherent Carrier Spin Dynamics in FAPbBr3 Perovskite Crystals.

Coherent spin dynamics of electrons and holes are studied in hybrid organic-inorganic lead halide perovskite FAPbBr3 bulk single crystals using the time-resolved Kerr ellipticity technique at cryogenic temperatures. The Larmor spin precession of the carrier spins in a magnetic field is monitored to measure the Landé g-factors of electrons (+2.44) and holes (+0.41). These g-factors are highly isotropic. The measured spin dephasing times amount to a few nanoseconds, and the longitudinal hole spin relaxation time is 470 ns. The important role of the strong hyperfine interaction between carrier spins and nuclear spins is demonstrated via dynamic nuclear polarization. At low temperatures, electron and hole spin relaxation predominantly occurs via the hyperfine interaction, whose importance significantly decreases at temperatures above 12 K. We overview the spin dynamics in various lead halide perovskite crystals and polycrystalline films and conclude on their common features provided by charge carrier localization at cryogenic temperatures.

Imidazoanthraquinone Derivative as a Surface Passivator for Enhanced and Stable Perovskite Solar Cells.

Hybrid organic-inorganic perovskites have been investigated for their potential to serve in next-generation perovskite solar cells (PSCs). While PSC technology is approaching commercialization, thermal and moisture stabilities remain a concern. Here, we describe the assembly of PSCs using an imidazoanthraquinone derivative (AQ) as a small organic additive to enhance the device performance and stability. Unlike polymer additives, AQ is easy to synthesize and is more economical. AQ was synthesized because it has both carbonyl and imidazole functional groups. The presence of C=O and N-H groups results in coordination interaction with Pb2+ and I- of the perovskite. Addition of the AQ molecule to methylammonium lead iodide leads to the formation of a superior crystalline perovskite film with fewer defects and enhanced stability under humid conditions. The use of optimized perovskite films enhanced device power conversion efficiency (PCE = 17.21%) compared to pristine perovskite (PCE = 13.88%). Unencapsulated optimized devices retained 90% of the initial power conversion efficiency for 30 days at a relative humidity of nearly 35%. The optimized films also exhibited superior thermal stability to that of pristine perovskite films.

MAPbI3 perovskite photodetectors for high-performance optical wireless communication

High-sensitivity and fast-response photodetectors (PDs) are vital part of optical wireless communication (OWC) system. In this work, we develop an organic–inorganic hybrid perovskite material (MAPbI3) based p–i–n structured PD. By optimizing the precursor solution concertation, the PD showed a high responsivity of 0.98 A W−1, a fast response time t rise/t fall of 12/12.5 μs, a specific detectivity of 2.62 × 1013 Jones, and the f−3dB of 24 kHz under the 532 nm laser and −0.2 V bias voltage. Furthermore, we designed an OWC system based on the prepared PD. With the baud rate of 19200 bps, the system exhibits a bit error rate less than 10−6, and it can realize 9.63 m long-distance communication and quick transmission applications such as strings, texts, photos, and audios. Our work demonstrates the great application potential of perovskite PDs in the field of optical communication.