Double Electron Transport Layers Research Articles

The combination of DFT and OghmaNano framework to study the heat stability and minimizing voltage losses in perovskite solar cells

This study employs DFT calculation to inspect the influence of Zirconium (Zr) element on heat stability and minimizing voltage losses in perovskite solar cells (PSCs) electron transport layer (ETL) constructed from TiO2 bulk semiconductor. The band structure (BS), density of states (TDOS and PDOS), optical dielectric properties, refractive index, extinction coefficient, absorption coefficient, and energy loss phenomena for both pristine TiO2 and Zr-doped TiO2 were comprehensively analyzed. To keep the empirical results consistent, organic and hybrid material Nano (OghmaNano) simulation tools were used to simulate the behavior of 6.25 % Zr-doped TiO2 as an ETL within PSCs. Further simulation explored PSCs' electrical and optical behavior utilizing CH3NH3PbI3 with Zr-doped TiO2 as the ETL. Crucial parameters were determined, including charge carrier density, charge carrier recombination, quantum efficiency, I–V characteristics, device performance, and heat stability. The significant results of this study establish the fact that Zr doping into the TiO2 produces good device performance and maintains thermal stability in PSCs. Interestingly, the band gap achieved from BS and the density of states for pure and doped TiO2 were almost the same. A comparative evaluation of the effects of double ETL structure devices, shedding light on their distinctive contributions to device architecture, was presented. This research provides valuable insights into optimizing efficiency and stability in PSCs for sustainable energy applications.

Tri-chalcogenides (Sb2S3/Bi2S3) solar cells with double electron transport layers: design and simulation

To make technology accessible to everyone, it is essential to focus on affordability and durability of the devices. Antimony trisulfide (Sb2S3) and bismuth (III) sulfide (Bi2S3) are low-cost and stable materials that are commonly used in photovoltaic devices due to their non-toxic nature and abundance. These materials are particularly promising for photovoltaic applications as they are effective light-absorbing materials. In this study, we utilized the Solar cell Capacitance Simulator- One-Dimensional (SCAPS-1D) software to investigate the parameters of a double electron transport layer (ETL) solar cell based on Sb2S3/ Bi2S3. The parameters examined included thickness of the absorber layer, overall defect density, density of acceptors, radiative recombination coefficient, series and shunt resistance, and work function of the back contact. The solar cell structure studied was FTO/SnO2/CdS/ Sb2S3 and Bi2S3/Spiro-OMeTAD/Au. By incorporating a SnO2 electron transport layer (ETL) into the double ETL structure of Sb2S3 and Bi2S3 solar cells, we observed a significant enhancement in the power conversion efficiency (PCE). Specifically, the PCE increased to 19.71% for the Sb2S3 solar cell and 24.05% for the Bi2S3 solar cell. In contrast, without SnO2, the single ETL-based CdS solar cell achieved a maximum PCE of 18.27 and 23.05% for Sb2S3 and Bi2S3, respectively.

Perovskite Solar Cells with Extremely High 24.63% Efficiency through Design of Double Electron Transport Layers and Double Luminescent Converter Layers

AbstractIntroduction of fluorescent down‐conversion layer inside perovskite solar cells (PSCs) can highly improve the ultraviolet response of the devices and the light stability. However, such a device is usually confronted with the problem of inter‐diffusion with the perovskite absorber layer, which severely limits its further development. To address this problem, herein, this work employs an interfacial dual electron transport layers (ETLs) strategy, sandwiching Cd‐CsPbCl3:Mn2+ luminescent quantum dots within gap of the ETLs, which not only reduces the interface energy level offset, but also improves the nucleation and crystallization kinetics of perovskite films and prevents their diffusion to the perovskite absorber layer. As a result, the efficient synergy effect effectively elevates both the open‐circuit voltage and fill factor of the PSCs, reaching maximum values of 1.181 V and 81.14%, respectively, finally delivering progressively increased device power conversion efficiency (PCE) of 24.32% with significantly improved light stability. To further improve the ultraviolet response, this work further adopts the strategy of dual fluorescent conversion layers inside and outside the PSCs, and finally obtains PCE of 24.63%, which is the best for various luminescent conversion cells. This work opens a new door for the development of efficient and stable photoluminescence conversion PSCs.

Optimization of ITO/V2O5/Alq3/TPBi/BPhen/LiF/Al Layers Configuration for OLED and Study of Its Optical and Electrical Characteristics

Nowadays, OLEDs have shown aesthetic potential in smart cards, sensor displays, other electronic devices, sensitive medical devices and signal monitoring etc. due to their wide range of applications like low power consumption, high contrast ratio, speed highly electroluminescent, wide viewing angle and fast response time. In this paper, a highly efficient organic LED ITO/V2O5/Alq3/TPBi/BPhen/LiF/Al with low turn-on voltage and high optically efficiency is presented including electrical and optical characteristics. The simulation of electrical characteristics like current versus applied voltage, current density versus applied voltage, recombination prefactor versus excess carrier density characteristics and optical characteristics like light flux versus current density, light flux versus applied voltage and optical efficiency versus applied voltage has been explained. The physical design, working principle and thickness of different layers along with the process of formation of singlet and triplet excitons are discussed in detail. Here double electron transport layer (ETL), cathode layers are used to enhance the electrical and optical efficiency of OLED. The operating voltage is found to be ~ 3.2 V for the ITO/V2O5/Alq3/TPBi/BPhen/LiF/Al heterostructure based OLED. The designed organic LED has achieved the maximum optical efficiency at 3 V.

Design of n-i-p and p-i-n Sb2Se3 solar cells: role of band alignment

Investigations into novel device architectures and interfaces that enhance charge transport and collection are necessary to increase the power conversion efficiency (PCE) of antimony selenide (Sb2Se3) solar cells, which have shown great promise as a low-cost and high-efficiency alternative to conventional silicon-based solar cells. The current work uses device simulations to design p-i-n and n-i-p Sb2Se3-based solar cell structures. The n-i-p configuration is investigated by comparing distinct electron transport layer (ETL) materials to get the best performance. While certain ETL materials may yield higher efficiencies, the J–V curve may exhibit S-shaped behavior if there is a misalignment of the bands at the ETL/absorber interface. To address this issue, a proposed double ETL structure is introduced to achieve proper band alignment and conduction band offset for electron transport. A PCE of 20.15% was achieved utilizing (ZnO/ZnSe) as a double ETL and Spiro-OMeTAD as a hole transport layer (HTL). Further, the p-i-n configuration is designed by proposing a double HTL structure to facilitate hole transport and achieve a proper valence band offset. A double HTL consisting of (CuI/CuSCN) is used in conjunction with ETL-free configuration to achieve a PCE of 21.72%. The simulation study is conducted using the SCAPS-1D device simulator and is validated versus a previously fabricated cell based on the configuration FTO/CdS/Sb2Se3/Spiro-OMeTAD/Au.

Interfacial engineering by applying double CdS structure electron transport layer for high-performance Sb2(S,Se)3 solar cells

Antimony sulfoselenide (Sb2(S,Se)3) has been demonstrated as a promising photoabsorber for stable inorganic thin film photovoltaics with high performance. Optimizing interfacial contact and reduce the defects are essential in restraining the recombination of photo-induced carrier at heterojunction interface. In particular, the electron transport layer (ETL) directly affects the quality of Sb2(S,Se)3 absorber layer as well as the performance of the device. Herein, an available and highly effective double CdS ETL is proposed to modify the heterojunction interface contact which moreover enhance the efficiency of Sb2(S,Se)3 solar cells. The optimal matching of the two CdS ETLs were fully investigated, and by following this process, the ETL with high crystallinity and density is obtained, rendering high-quality Sb2(S,Se)3 thin films as well. Besides, the final devices exhibit lower series resistance and larger Jsc, FF, enabling improvement of the efficiency from 3.09% to 6.94%. This study provides an effective method for the surface engineering of CdS ETLs to achieve high-performance Sb2(S,Se)3 solar cells.

Numerical Analysis of Stable (FAPbI3)0.85(MAPbBr3)0.15-Based Perovskite Solar Cell with TiO2/ZnO Double Electron Layer.

Although perovskite solar cells have achieved excellent photoelectric conversion efficiencies, there are still some shortcomings, such as defects inside and at the interface as well as energy level dislocation, which may lead to non-radiative recombination and reduce stability. Therefore, in this study, a double electron transport layer (ETL) structure of FTO/TiO2/ZnO/(FAPbI3)0.85(MAPbBr3)0.15/Spiro-OMeTAD is investigated and compared with single ETL structures of FTO/TiO2/(FAPbI3)0.85(MAPbBr3)0.15/Spiro-OMeTAD and FTO/ZnO/(FAPbI3)0.85(MAPbBr3)0.15/Spiro-OMeTAD using the SCAPS-1D simulation software, with special attention paid to the defect density in the perovskite active layer, defect density at the interface between the ETL and the perovskite active layer, and temperature. Simulation results reveal that the proposed double ETL structure could effectively reduce the energy level dislocation and inhibit the non-radiative recombination. The increases in the defect density in the perovskite active layer, the defect density at the interface between the ETL and the perovskite active layer, and the temperature all facilitate carrier recombination. Compared with the single ETL structure, the double ETL structure has a higher tolerance for defect density and temperature. The simulation outcomes also confirm the possibility of preparing a stable perovskite solar cell.

Design and Device Numerical Analysis of Lead-Free Cs2AgBiBr6 Double Perovskite Solar Cell

The advancement of lead-free double perovskite materials has drawn great interest thanks to their reduced toxicity, and superior stability. In this regard, Cs2AgBiBr6 perovskites have appeared as prospective materials for photovoltaic (PV) applications. In this work, we present design and numerical simulations, using SCAPS-1D device simulator, of Cs2AgBiBr6-based double perovskite solar cell (PSC). The initial calibrated cell is based on an experimental study in which the Cs2AgBiBr6 layer has the lowest bandgap (Eg = 1.64 eV) using hydrogenation treatment reported to date. The initial cell (whose structure is ITO/SnO2/Cs2AgBiBr6/Spiro-OMeTAD/Au) achieved a record efficiency of 6.58%. The various parameters that significantly affect cell performance are determined and thoroughly analyzed. It was found that the conduction band offset between the electron transport layer (ETL) and the Cs2AgBiBr6 layer is the most critical factor that affects the power conversion efficiency (PCE), in addition to the thickness of the absorber film. Upon engineering these important technological parameters, by proposing a double ETL SnO2/ZnO1-xSx structure with tuned absorber thickness, the PCE can be boosted to 14.23%.

Electron transport layer of tin dioxide deposited by reactive plasma and its application in perovskite solar cells

The electron transport layer is very important for the device efficiency and stability of perovskite solar cells. Tin dioxide is a common electron transport layer in high-efficiency solar cells and has good carrier extraction and transport capability. However, using the solution method to prepare tin dioxide, a large number of defects are generated on its surface during high-temperature annealing in air, which can degrade the electrical properties of the film, so the solution method is not conducive to preparing large-area film. In this paper, the reactive plasma deposition method is used to prepare tin dioxide thin film, and the performance of the thin film is optimized by adjusting the glow discharge time and working current. The film is applied to small-area N-I-P type perovskite solar cells, the efficiency reaching to 21.24%. The hysteresis of the device is improved by introducing stannous isooctanoate and tin dioxide as a double electron transport layer, the open circuit voltage of the solar cell increases from 1.11 to 1.15 V, the efficiency rises from 21.27% to 22.15%, and the hysteresis factor decreases from 24.04% to 3.69%. This work presents a new preparation method and effective optimization strategy to prepare tin dioxide electron transport layer, which will promote the development of planar heterojunction perovskite solar cells and provide a new research idea for preparing high-efficiency and stable perovskite solar cells.

52.4: Suppression of Initial Degradation for High‐Efficiency Solution‐Processed Organic Light Emitting Diodes

52.4: Suppression of Initial Degradation for High‐Efficiency Solution‐Processed Organic Light Emitting Diodes

Enhanced device performance of Cs2AgBiBr6 double perovskite photodetector by SnO2/ZnO double electron transport layer

In this study, we report the enhancement of device performance in a lead-free perovskite Cs2AgBiBr6-based deep blue photodetector by using a SnO2/ZnO double electron transport layer (ETL). The SnO2 layer was inserted to minimize the energy loss at the interface between the ZnO ETL and perovskite absorber layer by preparation of a smooth perovskite film. The hydrophilic SnO2 layer coating on the hydrophobic ZnO nanorods provides a uniform and high-quality perovskite layer without pinholes. Reduced contact angle measurement confirmed that the surface property changes towards hydrophilicity after insertion of a SnO2/ZnO double ETL compared with bare ZnO nanorods. Moreover, the introduction of the SnO2 layer leads to better carrier transportation and extraction by matching the energy level between the perovskite and ZnO ETL. The pinhole-free perovskite film and a well-matched energy level are responsible for the Cs2AgBiBr6-based visible photodetector with a SnO2/ZnO double ETL demonstrating simultaneous improvement of responsivity and specific detectivity by 12.7 times and 16.5 times, respectively, compared with those of the ZnO single ETL. From our results, we can suggest a guideline for an interface engineering strategy to improve perovskite optoelectronic device performance.

TiO2/SnO2 electron transport double layers with ultrathin SnO2 for efficient planar perovskite solar cells

The electron transport layer (ETL) plays an important role on the performance and stability of perovskite solar cells (PSCs). Developing double ETL is a promising strategy to take the advantages of different ETL materials and avoid their drawbacks. Here, an ultrathin SnO2 layer of ∼ 5 nm deposited by atomic layer deposit (ALD) was used to construct a TiO2/SnO2 double ETL, improving the power conversion efficiency (PCE) from 18.02% to 21.13%. The ultrathin SnO2 layer enhances the electrical conductivity of the double layer ETLs and improves band alignment at the ETL/perovskite interface, promoting charge extraction and transfer. The ultrathin SnO2 layer also passivates the ETL/perovskite interface, suppressing nonradiative recombination. The double ETL achieves outstanding stability compared with PSCs with TiO2 only ETL. The PSCs with double ETL retains 85% of its initial PCE after 900 hours illumination. Our work demonstrates the prospects of using ultrathin metal oxide to construct double ETL for high-performance PSCs.

Numerical investigation of the Cu2O solar cell with double electron transport layers and a hole transport layer

In this paper, a model of the Cu2O solar cell with double electron transport layers (ETLs) and a hole transport layer (HTL) has been investigated by SCAPS. Compared to the single ETL of ZnO, the problem of low open circuit voltage of the Cu2O solar cells can be improved by introducing the double ETLs of Zn(O,S)/ZnS. Our simulation results show that the sulfur concentration of Zn(O,S) and the donor density in double ETLs have a significant effect on device performance. The optimum S/S + O ratio and the best donor density are 0.82 and 8 × 1017cm−3, respectively. Due to the formation of an electron reflector and back surface field (BSF), an enhancement in both short circuit current density and open circuit voltage can be realized by introducing an appropriate HTL, and the best HTL is CuI, showing an efficiency of 12.15%. Then, the work function of metal electrode, the Cu2O thickness, the defect density and the acceptor density of Cu2O absorber layer, and the defect density at the Cu2O interfaces have been systematically investigated. After optimization, the best device efficiency of 16.49% can be achieved. Our results have demonstrated a new high-efficiency structure for cuprous oxide solar cells.

Enhanced Luminance of CdSe/ZnS Quantum Dots Light-Emitting Diodes Using ZnO-Oleic Acid/ZnO Quantum Dots Double Electron Transport Layer.

The widely used ZnO quantum dots (QDs) as an electron transport layer (ETL) in quantum dot light-emitting diodes (QLEDs) have one drawback. That the balancing of electrons and holes has not been effectively exploited due to the low hole blocking potential difference between the valence band (VB) (6.38 eV) of ZnO ETL and (6.3 eV) of CdSe/ZnS QDs. In this study, ZnO QDs chemically reacted with capping ligands of oleic acid (OA) to decrease the work function of 3.15 eV for ZnO QDs to 2.72~3.08 eV for the ZnO-OA QDs due to the charge transfer from ZnO to OA ligands and improve the efficiency for hole blocking as the VB was increased up to 7.22~7.23 eV. Compared to the QLEDs with a single ZnO QDs ETL, the ZnO-OA/ZnO QDs double ETLs optimize the energy level alignment between ZnO QDs and CdSe/ZnS QDs but also make the surface roughness of ZnO QDs smoother. The optimized glass/ITO/PEDOT:PSS/PVK//CdSe/ZnS//ZnO-OA/ZnO/Ag QLEDs enhances the maximum luminance by 5~9% and current efficiency by 16~35% over the QLEDs with a single ZnO QDs ETL, which can be explained in terms of trap-charge limited current (TCLC) and the Fowler-Nordheim (F-N) tunneling conduction mechanism.

Enhanced Device Performance of Cs2agbibr­6 Double Perovskite Photodetector by Sno2/Zno Double Electron Transport Layer

Enhanced Device Performance of Cs2agbibr­6 Double Perovskite Photodetector by Sno2/Zno Double Electron Transport Layer

Ionic-compound based high performance perovskite light emitting diodes

Metal halide perovskite has attracted much attention due to its adjustable color, high color purity, and excellent photoelectric properties. The quality of the perovskite film is one of the key factors that affect the performance of device. Here, PEA<sub>2</sub>Cs<sub><i>n</i>–1</sub>Pb<sub><i>n</i></sub>Br<sub>3<i>n</i>+1</sub> thin films are prepared by directly doping the ionic compound additive tetraphenylphosphine chloride (TPPCl) into the perovskite precursor of the light-emitting layer based on additive assisted technology. High-quality perovskite films with uniform, less pinholes and smaller grains are obtained. Not only is the photoluminescence (PL) performance of PeLEDs improved but the electroluminescence (EL) performance of PeLEDs with a double electron transport layer also turns better. The maximum brightness is 25285 cd/m<sup>2</sup>. The maximum current efficiency is 65.9 cd/A. And the maximum EQE is 17.3%. The method of adding ionic compounds to the perovskite precursor can not only improve the carrier transport behavior, but also make the formed small n crystal phases and large n crystal phase more balance, leading to the energy funnel effect to be enhanced. Further investigation by FTIR proves that the TPPCl can passivate the perovskite film, and thus greatly improving the EQE value of the PeLED. This researchpresents a simple and efficient method of developing high-performance quasi-two-dimensional green PeLEDs.

Enhanced Device Performance of Cs2agbibr­6 Double Perovskite Photodetector by Sno2/Zno Double Electron Transport Layer

Enhanced Device Performance of Cs2agbibr­6 Double Perovskite Photodetector by Sno2/Zno Double Electron Transport Layer

Physical mechanism of perovskite solar cell based on double electron transport layer

With their excellent photoelectric properties, perovskite solar cells have become the most promising photovoltaic devices in recent years. However, owing to defects and energy level misalignment, the non-radiative recombination loss of the perovskite solar cell will increase, which hinders the its efficiency and operational stability from being improved further. Therefore, it is very important to reduce the loss caused by energy level misalignment for realizing high-efficiency perovskite solar cells. In order to solve the above-mentioned problems, perovskite solar cell with dual electron transport layer (ETL) is studied in this work. The dual-layer structure forms a stepped conduction band structure to reduce the conduction band offset between the active layer and the transport layer, which reduces the interface recombination between the two structures and improves device performance. In addition, the influences of the defect density on the cell performance for the two ETL structures are also discussed. With the continuous increase of the defect density, the performance of the single-layer structure decreases more obviously. While the dual ETL structure can alleviate the performance dependence on the defect density in comparison with the single ETL structure. Therefore, the use of dual ETL can improve the performance of perovskite solar cells and defect tolerance, which provides guidance for designing high-performance solar cells.

Optimization of interfacial characteristics of antimony sulfide selenide solar cells with double electron transport layer structure

Antimony sulfide selenide thin film solar cells have drawn great interest in the field of photovoltaic due to their advantages of simple preparation method, abundant raw materials, non-toxic and stable photoelectric properties. After the development in recent years, the photoelectric conversion efficiency of antimony sulfide selenide solar cells has exceeded 10%, which has great development potential. In this work, the carrier recombination near n/i interface in antimony sulfide selenide solar cells is studied. It is found that the characteristics of the n/i interface are affected by the interfacial electron mobility and energy band structure. The improvement of the interface electron mobility can make the electrons more effectively transferred to the electron transport layer, and realize the effective improvement of the short circuit current density and fill factor of the device. Moreover, the introduction of ZnO/Zn<sub>1–<i>x</i></sub>Mg<sub><i>x</i></sub>O double electron transport layer structure can further optimize the performance of antimony sulfide selenide solar cells. The change of Zn<sub>1–<i>x</i></sub>Mg<sub><i>x</i></sub>O energy level position can adjust the energy level distribution of the interface and light absorption layer simultaneously. When the conduction band energy level of Zn<sub>1–<i>x</i></sub>Mg<sub><i>x</i></sub>O is –4.2 eV and the corresponding Mg content is 20%, the effect of restraining the carrier recombination is the most obvious, and the antimony sulfide selenide solar cell also obtains the best device performance. Finally, under the ideal condition of removing the defect state, the antimony sulfide selenide solar cells with 600 nm in thickness can achieve 20.77% theoretical photoelectric conversion efficiency. The research results provide theoretical and technical support for further optimizing and developing the antimony sulfide selenide solar cells.

Effective Double Electron Transport Layer Inducing Crystallization of Active Layer for Improving the Performance of Organic Solar Cells.

Interface modification plays an important role in enhancing the photoelectric conversion efficiency and stability of organic solar cells. In this work, alkali metal lithium chloride (LiCl) was introduced between indium tin oxide and polyethyleneimine ethoxylate (PEIE) to prepare a double-layer electron transport layer. Results show that the introduction of LiCl has dual functions. The first function is that LiCl can enhance conductivity, thereby facilitating charge collection. The second function is that the double-layer electron transport layer based on LiCl can induce the crystallization of active layer, thereby enhancing charge transport. Devices with LiCl/PEIE double layer achieve a high power conversion efficiency (PCE) of 3.84%, which is 21.5% higher than that of pristine devices (the PCE of pristine devices with pure PEIE interface layer is 3.16%).