Layer For Perovskite Solar Cells Research Articles

Exploring the potential of CsPbI3/CsPbBr3 heterojunction as an absorber layer in perovskite solar cells: a numerical and experimental study

Exploring the potential of CsPbI3/CsPbBr3 heterojunction as an absorber layer in perovskite solar cells: a numerical and experimental study

Tungsten-Doped ZnO as an Electron Transport Layer for Perovskite Solar Cells: Enhancing Efficiency and Stability.

This study delves into enhancing the efficiency and stability of perovskite solar cells (PSCs) by optimizing the surface morphologies and optoelectronic properties of the electron transport layer (ETL) using tungsten (W) doping in zinc oxide (ZnO). Through a unique green synthesis process and spin-coating technique, W-doped ZnO films were prepared, exhibiting improved electrical conductivity and reduced interface defects between the ETL and perovskite layers, thus facilitating efficient electron transfer at the interface. High-quality PSCs with superior ETL demonstrated a substantial 30% increase in power conversion efficiency (PCE) compared to those employing pristine ZnO ETL. These solar cells retained over 70% of their initial PCE after 4000 h of moisture exposure, surpassing reference PSCs by 50% PCE over this period. Advanced numerical multiphysics solvers, employing finite-difference time-domain (FDTD) and finite element method (FEM) techniques, were utilized to elucidate the underlying optoelectrical characteristics of the PSCs, with simulated results corroborating experimental findings. The study concludes with a thorough discussion on charge transport and recombination mechanisms, providing insights into the enhanced performance and stability achieved through W-doped ZnO ETL optimization.

Reducing oxygen vacancies of MoO3 by polyaniline functionalization for stable and efficient inorganic tri-brominated perovskite solar cells

The photovoltaic performance of perovskite solar cells (PSCs) is closely dependent on the efficient carrier extraction and transport at the interface. Here, a polyaniline (PANI) functionalized MoO3 (PANI/MoO3) hole transport material (HTM) is exploited to perfect the interface between the perovskite layer and carbon electrode in all-inorganic CsPbBr3 PSCs. After functionalization with PANI, the p-type behavior and the hole mobility and conductivity of MoO3 are improved by reducing the oxygen vacancies, which boosts the hole extraction and transport, energy level arrangement at the interface of CsPbBr3 perovskite/(PANI/MoO3) HTM. Meanwhile, the PANI/MoO3 with rich C-N and N-H groups introduced by PANI passivates the ions trap states of perovskite films by the C-N···Pb2+ (Cs+) Lewis acid-base coordination and the N-H···Br- hydrogen bonding, leading to an effective suppression of non-radiative recombination for improved carrier extraction. As a result, the PANI/MoO3 HTMs-based CsPbBr3 PSCs obtain a remarkably increased power conversion efficiency of 10.41%, in comparison with the efficiency of the original device (6.55%). In addition, the unencapsulated device with PANI/MoO3 HTMs shows excellent long-term stability with 93.9% maintenance of the initial efficiency after storing in air with 85% relative humidity and at 85 °C for 30 days.

Effect of Al Dope with ZnO Electron Transport Layer in Perovskite Solar Cells Using SCAPs 1-D Simulation

Perovskite solar cells have shown exceptional performance and significant advancements in solar cell efficiency. For perovskite solar cells to conduct electrons and generate current, one of the key components is the substance known as the electron transport layer (ETL). Using the SCAPS 1D modelling program, ZnO: Al was used in this instance as the ETL material in a perovskite solar cell. Because of its interaction with the perovskite material, the ZnO: Al ETL demonstrated high cell efficiency. The performance of the ZnO: Al-doped-based solar cell achieved a PCE as high as 23.5%. In the meanwhile, the greatest cell performance in terms of enhancing the charge transport mechanism and raising cell efficiency was shown by perovskite solar cells doping the ETL with Al and having the right layer thickness. Thus, throughout the manufacturing process, the parameters used in this study may serve as a guide.

Theoretical Study of Inorganic Charge Transport Layer of Perovskite Solar Cells Using Scaps Software

Theoretical Study of Inorganic Charge Transport Layer of Perovskite Solar Cells Using Scaps Software

Non-destructive buffer enabling near-infrared-transparent inverted inorganic perovskite solar cells toward 1400 h light-soaking stable perovskite/Cu(In,Ga)Se2 tandem solar cells

Near-infrared (NIR) transparent inverted all-inorganic perovskite solar cells (PSCs) are excellent top cell candidates in tandem applications. An essential challenge is the replacement of metal contacts with transparent conductive oxide (TCO) electrodes, which requires the introduction of a buffer layer to prevent sputtering damage. In this study, we show that the conventional buffers (i.e., small organic molecules and atomic layer deposited metal oxides) used for organic-inorganic hybrid perovskites are not applicable to all-inorganic perovskites, due to non-uniform coverage of the vulnerable layers underneath, deterioration upon ion bombardment and moisture induced perovskite phase transition. A thin film of metal oxide nanoparticles by the spin-coating method serves as a non-destructive buffer layer for inorganic PSCs. All-inorganic inverted near-infrared-transparent PSCs deliver a PCE of 17.46% and an average transmittance of 73.7% between 780 and 1200 nm. In combination with an 18.56% Cu(In,Ga)Se2 bottom cell, we further demonstrate the first all-inorganic perovskite/CIGS 4-T tandem solar cell with a PCE of 24.75%, which exhibits excellent illumination stability by maintaining 86.7% of its initial efficiency after 1400 h. The non-destructive buffer lays the foundation for efficient and stable NIR-transparent inverted inorganic perovskite solar cells and perovskite-based tandems.

Enhancement of Efficiency of Perovskite Solar Cells with Hole-Selective Layers of Rationally Designed Thiazolo[5,4-d]thiazole Derivatives.

We introduce thiazolo[5,4-d]thiazole (TT)-based derivatives featuring carbazole, phenothiazine, or triphenylamine donor units as hole-selective materials to enhance the performance of wide-bandgap perovskite solar cells (PSCs). The optoelectronic properties of the materials underwent thorough evaluation and were substantially fine-tuned through deliberate molecular design. Time-of-flight hole mobility TTs ranged from 4.33 × 10-5 to 1.63 × 10-3 cm2 V-1 s-1 (at an electric field of 1.6 × 105 V cm-1). Their ionization potentials ranged from -4.93 to -5.59 eV. Using density functional theory (DFT) calculations, it has been demonstrated that S0 → S1 transitions in TTs with carbazolyl or ditert-butyl-phenothiazinyl substituents are characterized by local excitation (LE). Mixed intramolecular charge transfer (ICT) and LE occurred for compounds containing ditert-butyl carbazolyl-, dimethoxy carbazolyl-, or alkoxy-substituted triphenylamino donor moieties. The selected derivatives of TT were used for the preparation of hole-selective layers (HSL) in PSC with the structure of glass/ITO/HSLs/Cs0.18FA0.82Pb(I0.8Br0.2)3/PEAI/PC61BM/BCP/Ag. The alkoxy-substituted triphenylamino containing TT (TTP-DPA) has been demonstrated to be an effective material for HSL. Its layer also functioned well as an interlayer, improving the surface of control HSL_2PACz (i.e., reducing the surface energy of 2PACz from 66.9 to 52.4 mN m-1), thus enabling precise control over perovskite growth energy level alignment and carrier extraction/transportation at the hole-selecting contact of PSCs. 2PACz/TTP-DPA-based devices showed an optimized performance of 19.1 and 37.0% under 1-sun and 3000 K LED (1000 lx) illuminations, respectively. These values represent improvements over those achieved by bare 2PACz-based devices, which attained efficiencies of 17.4 and 32.2%, respectively. These findings highlight the promising potential of TTs for the enhancement of the efficiencies of PSCs.

Zinc oxide doped with graphene quantum dots as improved electron transport layers for planner perovskite solar cells

Zinc oxide (ZnO), a material with excellent electron mobility and a low-temperature requirement for production, is a promising option for use as an electron transport layer in perovskite solar cells (PSCs). However, it does have the drawback of having a low open-circuit voltage ([Formula: see text]). Herein, to increase the [Formula: see text] parameter of ZnO-based PSCs, graphene quantum dots (GQDs) are incorporated into the ZnO precursor and used as desirable ETL for PSCs. The presence of GQDs in ZnO ETL facilitated photo-electrons at the ETL/perovskite interface by reducing charge transfer resistance in this interface. Compared to the net ZnO-based PSCs, solar cells using GQD-doped ZnO as ETL have better stability, comparable [Formula: see text], higher [Formula: see text], and FF. The best GQD-doped-ZnO ETL-based PSCs recorded the highest power conversion efficiency of 20.23% with [Formula: see text] of 1.130[Formula: see text]V. Meanwhile, the boosted PCE of FAPbI3-based PSCs is achieved due to the improved perovskite crystal quality, the effective defect passivation effect of GQDs at ZnO/FAPbI3 interface, and the increased electrical conductivity of ZnO ETL. In addition, the GQD-doped ETL devices showed higher ambient air stability than the devices with net ZnO ETLs.

Exploring the potential of green synthesized ZnO-SnO2 composite as an effective electron transport layer for perovskite solar cells: A sustainable approach

Utilizing green-synthesized ZnO nanoparticles as an electron transport layer (ETL) is a key strategy in perovskite solar cell applications, leveraging their high electron mobility, conductivity, stability against photo-corrosion, and cost-effectiveness. In this study, these environmentally synthesized nanoparticles, combined with SnO2, formed a composite solution-processed ETL achieving an impressive 18.09 % device efficiency, with 1.06 V open circuit voltage, 71.71 % fill factor, and 23.80 mA/cm2 short circuit current density. These values underscore the composite material's potential for device applications. Additionally, capacitance measurements investigated ETL and absorber layer interfaces, yielding crucial insights into their behaviour under varying voltage, frequency, and illumination conditions. The study highlights the ZnO-NP and SnO2 composite's efficacy as a superior ETL in PSCs, emphasizing the environmental sustainability implications of employing green-synthesized materials in solar energy technologies.

Properties of AZO films grown by ALD applied as a TCO layer in perovskite solar cells

Properties of AZO films grown by ALD applied as a TCO layer in perovskite solar cells

Surface Modification of TiO2 for High Performance in all Inorganic Perovskite Solar Cells

Titanium dioxide ([Formula: see text]) is a commonly employed electron transport layer in perovskite solar cells (PSCs) due to its exceptional attributes such as high mobility, a wide bandgap and remarkable stability against moisture and high temperatures. This holds particularly true for inorganic PSCs. Nevertheless, the substantial hysteresis and elevated trap defect levels following annealing present challenges to enhance the efficiency of the PSCs. Herein, we proposed a chemical bath deposition (CBD) method to fabricate the [Formula: see text] layer, serving as the electron transport layer in [Formula: see text] solar cells. This method is coupled with KCl, which supplies an ample quantity of [Formula: see text] ions capable of diffusing into the [Formula: see text] perovskite film during the annealing process. The inclusion of [Formula: see text] ions significantly diminishes the solar cell hysteresis and enhances the crystalline quality of the perovskite material, thereby enhancing the performance of [Formula: see text] solar cells. By implementing the [Formula: see text] and KCl treatments, we achieved an impressive efficiency of 9.49%. Furthermore, the device also exhibited excellent stability in air for 30 days.

Enhancing CsSn0.5Ge0.5I3 Perovskite Solar Cell Performance via Cu2O Hole Transport Layer Integration

Perovskite solar cells (PSCs) have emerged as a promising alternative to traditional silicon solar cells due to their low cost of fabrication and high power conversion efficiency (PCE). The utilization of lead halide perovskites as absorber layers in perovskite solar cells has been impeded by two major issues: lead poisoning and stability concerns. These hindrances have greatly impeded the industrialization of this cutting-edge technology. In light of the harmful effects of lead in perovskite solar cells, researchers have shifted their attention to exploring lead-free metal halide perovskites. However, the present alternatives to lead-based perovskite exhibit poor performance, thus prompting further inquiry into this matter. The primary objective of this research is to investigate the use of Cu2O as a hole transport layer in combination with lead-free metal halide perovskite (CsSn0.5Ge0.5I3) to achieve superior performance. Through meticulous experimentation, the suggested model has achieved outstanding results by optimizing several key variables. These variables include the thickness of the absorber layer (CsSn0.5Ge0.5I3), defect density, and doping densities, as well as the back contact work function and the operating temperature associated with each layer. The proposed FTO/PC60BM/CsSn0.5Ge0.5I3/Cu2O/Au solar cell structure surpassed prior configurations by comprehensively examining key aspects such as absorber layer thickness and defect density, doping densities, and back contact work. The structure has been also compared with multiple electron transport elements and concluded that the proposed model functions superior due to the use of PC60BM as an electron transport layer and it has an improved electron extraction procedure. Finally, the proposed model has achieved the optimized values as Jsc of 31.56 mA/cm-2, Voc of 1.12 V, FF of 81.47%, and PCE of 27.72%. As a consequence of this research, the investigated structure may be an excellent contender for the eventual creation of lead-free solar power cells made from perovskite.

Dual Defect Passivation at the Buried Interface for Printable Mesoscopic Perovskite Solar Cells with Reduced Open-Circuit Voltage Loss.

Numerous defects exist at the buried interface between the perovskite and adjacent electron transport layers in perovskite solar cells, resulting in severe non-radiative recombination and excessive open-circuit voltage (VOC) loss. Herein, a dual defect passivation strategy utilizing guanidine sulfate (GUA2SO4) as an interface modifier is first reported. On the one hand, the SO4 2- preferentially interacts with Pb-related defects, generating water-insoluble lead oxysalts complexes. Additionally, GUA+ diffuses into the perovskite and induces the formation of low-dimensional perovskite. These reactions effectively suppress trap states at the buried interface and perovskite boundaries in printable mesoscopic perovskite solar cells (p-MPSCs), thus increasing the carrier lifetime. Meanwhile, GUA2SO4 optimizes the interface energy band alignment, thus accelerating the charge extraction and transfer at the buried interface. This synergistic effect of trap passivation and interface energy band alignment modulation is strongly demonstrated by an increase in average VOC of 70mV and the power conversion efficiency improvement from 17.51% to 18.70%. This work provides a novel approach to efficiently improve the performance of p-MPSCs through dual-targeted defect passivation at the buried interface.

Single Crystal Seed Induced Epitaxial Growth Stabilizes α-FAPbI3 in Perovskite Solar Cells.

FAPbI3 stands out as an ideal candidate for the photoabsorbing layer of perovskite solar cells (PSCs), showcasing outstanding photovoltaic properties. Nonetheless, stabilizing photoactive α-FAPbI3 remains a challenge due to the lower formation energy of the competitive photoinactive δ-phase. In this study, we employ tetraethylphosphonium lead tribromide (TEPPbBr3) single crystals as templates for the epitaxial growth of PbI2. The strategic use of TEPPbBr3 optimizes the evolution of intermediates and the crystallization kinetics of perovskites, leading to high-quality and phase-stable α-FAPbI3 films. The TEPPbBr3-modified perovskite exhibits optimized carrier dynamics, yielding a champion efficiency of 25.13% with a small voltage loss of 0.34 V. Furthermore, the target device maintains 90% of its initial PCE under maximum power point (MPP) tracking over 1000 h. This work establishes a promising pathway through single crystal seed based epitaxial growth for achieving satisfactory crystallization regulation and phase stabilization of α-FAPbI3 perovskites toward high-efficiency and stable PSCs.

A Multifunctional Dye Molecule as the Interfacial Layer for Perovskite Solar Cells.

In perovskite solar cells (PSCs), defects in the interface and mismatched energy levels can damage the device performance. Improving the interface quality is an effective way to achieve efficient and stable PSCs. In this work, a multifunctional dye molecule, named ThPCyAc, was designed and synthesized to be introduced in the perovskite/HTM interface. On one hand, various functional groups on the acceptor unit can act as Lewis base to reduce defect density and suppress nonradiative combinations. On the other hand, the stepwise energy-level alignment caused by ThPCyAc decreases the accumulation of interface carriers for facilitating charge extraction and transmission. Therefore, based on the ThPCyAc molecule, the devices exhibit elevated open-circuit voltage and fill factor, resulting in the best power conversion efficiency (PCE) of 23.16%, outperforming the control sample lacking the interface layer (PCE = 21.49%). Excitingly, when attempting to apply it as a self-assembled layer in inverted devices, ThPCyAc still exhibits attractive behavior. It is worth noting that these results indicate that dye molecules have great potential in developing multifunctional interface materials to obtain higher-performance PSCs.

Fluorinated Polyimide Tunneling Layer for Efficient and Stable Perovskite Photovoltaics

AbstractDespite the remarkable progress of perovskite solar cells (PSCs), challenges remain in terms of finding effective and viable strategies to enhance their long‐term stability while maintaining high efficiency. In this study, a new insulating and hydrophobic fluorinated polyimide (FPI: 6FDA‐6FAPB) was used as the interface layer between the perovskite layer and the hole transport layer (HTL) in PSCs. The functional groups of FPI play a pivotal role in passivating interface defects within the device. Due to its high work function, FPI demonstrates field‐effect passivation (FEP) capabilities as an interface layer, effectively mitigating non‐radiative recombination at the interface. Notably, the FPI insulating interface layer does not impede carrier transmission at the interface, which is attributed to the presence of hole tunneling effects. The optimized PSCs achieve an outstanding power conversion efficiency (PCE) of 24.61 % and demonstrate excellent stability, showcasing the efficacy of FPI in enhancing device performance and reliability.

Fluorinated Polyimide Tunneling Layer for Efficient and Stable Perovskite Photovoltaics.

Despite the remarkable progress of perovskite solar cells (PSCs), challenges remain in terms of finding effective and viable strategies to enhance their long-term stability while maintaining high efficiency. In this study, a new insulating and hydrophobic fluorinated polyimide (FPI: 6FDA-6FAPB) was used as the interface layer between the perovskite layer and the hole transport layer (HTL) in PSCs. The functional groups of FPI play a pivotal role in passivating interface defects within the device. Due to its high work function, FPI demonstrates field-effect passivation (FEP) capabilities as an interface layer, effectively mitigating non-radiative recombination at the interface. Notably, the FPI insulating interface layer does not impede carrier transmission at the interface, which is attributed to the presence of hole tunneling effects. The optimized PSCs achieve an outstanding power conversion efficiency (PCE) of 24.61 % and demonstrate excellent stability, showcasing the efficacy of FPI in enhancing device performance and reliability.

Structural, Mechanical, and Optoelectronic Properties of CH3NH3PbI3 as a Photoactive Layer in Perovskite Solar Cell

The structural, electronic, mechanical, and optical properties of pseudo-cubic CH3NH3PbI3 perovskite have been studied within the framework of density functional theory, in line with solar cell applications. The computed values of lattice and elastic constants concurred with the available theoretical and experimental data. This compound has a semi-conducting behavior, with a direct band gap of about 1.49 eV. Note that the solar radiation spectrum has a maximum energy intensity value of approximately 1.50 eV. Thus, semiconductors with such gaps are preferred for photovoltaic applications. Its elastic parameters reveal that it is a ductile material that is mechanically stable. Optical descriptors such as refractive index, reflectivity, extinction, energy loss, and absorption have been explored with the aim of establishing the optical features of the material. Our findings demonstrate that this perovskite is suitable for solar cell applications based on the size and nature of the band gap, as also supported by the obtained upper limit value of simulated power conversion efficiency via the spectroscopic limited maximum efficiency mathematical model.

Wide-bandgap donor polymers from organic photovoltaics as dopant-free hole transport layers for perovskite solar cells

Dopant-free polymer hole transport materials (HTMs) exhibit high thermal stability, hydrophobicity and film-processing capabilities, demonstrating excellent device efficiency and stability in perovskite solar cells (PSCs). Continued innovation of wide-bandgap polymers in organic photovoltaics (OPV) provides a valuable toolbox for developing polymeric HTMs. Here, we propose an effective molecule design for selecting structurally relevant polymers (D18, D18-Cl, PBQx-TCl) available for commercialization. We discover that the highly planar conjugated backbones play a crucial role in regulating the packing orientation of the film relative to the perovskite. The moderate aggregation with face-on packing orientation is conducive to the high-quality film, which is responsible for better contact with perovskite and superior charge extraction and transport. Simultaneously, these polymers with robust passivation enhanced the open circuit voltage (VOC) without additional passivation layers, streamlining the device process. Consequently, a PSC using dopant-free PBQx-TCl HTL demonstrated an efficiency of 24.12 % with a high VOC of 1.20 V and good operational stability (T90 > 600 h). This work reveals transparent structure–function-performance relationships between molecules and devices, paving the way for the subsequent development of high-performance HTMs.

Surface modification of halide perovskite using EDTA-complexed SnO2 as electron transport layer in high performance solar cells.

The long-term performance of metal halide perovskite solar cells (PSCs) can be significantly improved by tuning the surface characteristics of the perovskite layers. Herein, low-temperature-processed ethylenediaminetetraacetic acid (EDTA)-complexed SnO2 (E-SnO2) is successfully employed as an electron transport layer (ETL) in PSCs, enhancing the efficiency and stability of the devices. The effects of EDTA treatment on SnO2 are investigated for different concentrations: comparing the solar cells' response with 15%-2.5% SnO2 and E-SnO2 based ETLs, and it was found that 7.5% E-SnO2 provided the best results. The improved surface properties of the perovskite layer on E-SnO2 are attributed to the presence of small amount of PbI2 which contributes to passivate the defects at the grain boundaries and films' surface. However, for the excess PbI2 based devices, photocurrent dropped, which could be attributed to the generation of shallow traps due to excess PbI2. The better alignment between the Fermi level of E-SnO2 and the conduction band of perovskite is another favorable aspect that enables increased open-circuit potential (VOC), from 0.82 V to 1.015 V, yielding a stabilized power conversion efficiency of 15.51%. This complex ETL strategy presented here demonstrates the enormous potential of E-SnO2 as selective contact to enhance the perovskite layer properties and thereby allow stable and high-efficiency PSCs.