Hole Transport Layer Thickness Research Articles

Designing PEDOT: PSS/Si hybrid solar cells via numerical simulation: optimum selection of the absorber and hole transport layer thickness and defect density

Numerical investigation of PEDOT: PSS/Si heterostructures was carried out using solar cell capacitance simulation (SCAPS 1D) in which experimentally observed absorbance of PEDOT: PSS was incorporated. The defect density of PEDOT: PSS, the defect density of n-Si, and the donor doping density of n-type silicon wafer were investigated based on the optimized absorption coefficient of n-type silicon wafer. The optimized value of PEDOT: PSS thickness, doping density, and the defect density of both PEDOT: PSS and n-Si were determined. The contour colour mapping tool was used to predict the efficiency region of the heterojunction solar cell. 21.2% efficient PEDOT: PSS/n-Si hybrid solar cells resulted after optimizing the parameters.

Numerical modelling of an effective perovskite solar cell and PV-module for comparison analysis of organic and inorganic electron transport layers

The demand for energy has increased over the past few decades due to both the industrial sector's rapid development and the world's population growth. As we know, the main source of energy consists primarily of fossil fuels, which are expected to be exhausted very soon. Researchers were therefore urged to locate an alternative source of energy that may substitute for fossil fuels in order to meet the world's growing energy needs. Substitute energy sources, like renewable energy, can be used to reduce reliance on conventional energy. As its irradiance may produce electricity when struck by photovoltaic solar (PV) panels, one of the increasingly prevalent types of energy is solar energy. With the help of capacitance simulator software for solar cells (SCAPS-1D), a thorough study of comparison analysis for the design of more efficient, inexpensive, and non-toxic Ni/Cu2O/MASnI3/PCBM/FTO and Ni/Cu2O/MASnI3/WO3/FTO module configurations of solar cells was carried out, and the PVsyst photovoltaic software package investigated the dependence of solar panels on temperature and irradiation. In order to investigate how altering the electron transport layer (ETL) affects conversion efficiency, this work offers a perovskite solar cell simulation with both organic and inorganic ETLs. The absorber layer of perovskite and the HTL (hole transport layer) are maintained uniformly across all ETL configurations. This particular research takes into account the CH3NH3SnI3 absorber layer with Cu2O as HTL. In order to determine which cell combination has the maximum conversion efficiency, we examine the outcomes of both cell combinations. The SCAPS-1D software is used for all simulation work. The power conversion efficiency (PCE) for organic ETL was found to be 28.79%., in addition to a number of electrical parameters like short-circuit current density (Jsc) of 33.42mA/cm2, open-circuit voltage (Voc) of 1.032V, and fill factor (FF) of 83.43%. For inorganic ETL, PCE was 29.54%, Jsc was 34.28mA/cm2, Voc was 1.033, and fill factor was 83.34%. The optimised layer thickness of HTL was 0.2µm, for ETL it was 0.02µm, and the CH3NH3SnI3 absorber layer was 0.8µm. For a solar module with 72 cells with dimensions of 2.2×1.1m, the results obtained from the simulation of electrical parameters derived from SCAPS-1D were configured in the PVsyst software package for panel performance.

Elucidating Interfacial Hole Extraction and Recombination Kinetics in Perovskite Thin Films

Hybrid organic–inorganic perovskite solar cells (PSCs) are receiving huge attention owing to their marvelous advantages, such as low cost, high efficiency, and superior optoelectronics characteristics. Despite their promising potential, charge-carrier dynamics at the interfaces are still ambiguous, causing carrier recombination and hindering carrier transport, thus lowering the open-circuit voltages (Voc) of PSCs. To unveil this ambiguous phenomenon, we intensively performed various optoelectronic measurements to investigate the impact of interfacial charge-carrier dynamics of PSCs under various light intensities. This is because the charge density can exhibit different mobility and charge transport properties depending on the characteristics of the charge transport layers. We explored the influence of the hole transport layer (HTL) by investigating charge transport properties using photoluminescence (PL) and time-resolved (TRPL) to unveil interfacial recombination phenomena and optoelectronic characteristics. We specifically investigated the impact of various thicknesses of HTLs, such as 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD), and poly(triaryl)amine (PTAA), on FA0.83MA0.17Pb(Br0.05I0.95)3 perovskite films. The HTLs are coated on perovskite film by altering the HTL’s concentration and using F4-TCNQ and 4-tert-butylpyridine (tBP) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSi) as dopants both for spiro-OMeTAD and PTAA. These HTLs diversified the charge concentration gradients in the absorption layer, thus leading to different recombination rates based on the employed laser intensities. At the same time, the generated charge carriers are rapidly transferred to the interface of the HTL/absorption layer and accumulate holes at the interface because of inefficient capacitance and mobility differences caused by differently doped HTL thicknesses. Notably, the charge concentration gradient is low at lower light intensities and did not accumulate holes at the HTL/absorption layer interface, even though they have high charge mobility. Therefore, this study highlights the importance of interfacial charge recombination and charge transport phenomena to achieve highly efficient and stable PSCs.

Enhanced Conversion Efficiency in MAPbI3 Perovskite Solar Cells through Parameters Optimization via SCAPS-1D Simulation

In this study, various factors affecting the efficiency of the MAPbI3 perovskite solar cell (PSC) were analyzed using the SCAPS-1D simulation program. The basic device analyzed in this study had a structure of ITO/TiO2/MAPbI3/Cu2O/Au. The thickness of each layer (electron transport layer (ETL), perovskite absorption layer (PAL), and hole transport layer (HTL)), PAL defect density and interface defect density were investigated as parameters. The optimized parameters that yielded the highest light conversion efficiency were an ETL (TiO2) thickness of 100 nm, a PAL (MAPbI3) thickness of 1300 nm, an HTL (Cu2O) thickness of 400 nm, a PAL defect density of 1014 cm−3, and an interface defect density of 1013 cm−3 for both absorber/ETL and absorber/HTL interfaces. The optimized PSC exhibited a maximum efficiency of 19.30%. These results obtained in this study are expected to contribute considerably to the optimization and efficiency improvement of perovskite solar cells using inorganic charge-carrier transport layers.

Performance evaluation of an eco-friendly and highly efficient FASnI3-based perovskite solar cell using Mg-doped CuCrO2 as HTL

Perovskite-based solar cells have emerged as promising photovoltaic devices. However, challenges involving unstable and toxic materials hinder their commercial use. Addressing these issues, the investigation incorporates a non-toxic tin-based absorber layer and specific inorganic charge transporter materials. The focus is on formamidinium tin iodide (FASnI3) based perovskite solar cells (PSCs), known for their efficiency, lead-free composition, and environmental friendliness. Zinc oxy-sulphide (ZnO0.25S0.75) serves as the electron transport layer (ETL) due to its 3.03 eV band gap. Magnesium doped copper delafossite (Mg–CuCrO2) acts as the hole transport layer (HTL) for its 3.3 eV band gap and its ability to maintain device stability. The proposed structure Au/Mg–CuCrO2/FASnI3/ZnO0.25S0.75/TCO was analyzed using numerical simulation conducted with the solar cell capacitance simulator (SCAPS-1D). Performance parameters of the structure were assessed by varying FASnI3 absorber layer thickness, defect density, and doping concentration. Variations in ETL and HTL thickness, defect density, and electron affinity were also explored. Effects of interface defects, series resistance, shunt resistance, and temperature on the device were examined. The optimized device achieved Voc of 1.2462 V, Jsc of 27.98 mA/cm2, FF of 89.33%, and PCE of 31.16%. This level of efficiency holds significant promise as an alternative for a highly effective environmentally friendly solar absorber material in photovoltaic applications.

Correlation between defect properties and the performance of eco-friendly CsSnI3-based perovskite solar cells

This study investigates the potential use of eco-friendly, all-inorganic cesium tin iodide (CsSnI3) perovskite (PVK) as an absorber layer. Despite having higher temperature stability of CsSnI3, the challenge is to get a uniform and defect-free film that hinders the performance. To accomplish this goal, we investigated several performance-related variables for perovskite solar cells (PSCs), including material defect density (Nt ), transport materials, layer thickness, temperature impacts, and back contact work functions. Negative valence band or conduction band offset values indicate no barrier preventing photogenerated carriers from flowing into the charge transport layers. The simulation result shows that hole transport layer thickness shows a higher impact than electron transport layer thickness. For the PVK thickness of 500 nm and a carrier density of 1018 cm−3, the device offers an optimum power conversion efficiency of 20.1%. The performance is more significantly affected by the defects in the PVK material compared to the defects present at the interface. Higher recombination (Re−h+) occurs at the TiO2–CsSnI3 interface. Defects located within the deep-level trap positioned at the mid-point of the band gap energy (E g) have a negative impact on the performance. The temperature coefficient (C T) is approximately ‒0.367% K‒1, indicating excellent thermal stability in an open environment. The selection of ‘A’ cation, the addition of additives, or carefully controlled fabrication techniques can mitigate the defect. This research shows the strategy for creating defects-free PSC devices, ultimately enhancing performance and the stability.

Effect of hole-transport layer thickness on the performance of organic light-emitting diodes

In this study, we investigated the influence of hole-transport layer thickness (0, 5, 10, 15, 20, 25, 30, 35 and 40 nm), N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine (α-NPD) on the performance of thermally evaporated multilayer organic light-emitting diodes (OLEDs) with tris(8-hydroxy-quinolinato)aluminium (Alq3) as electroluminescent material. A device with 5 nm α-NPD thickness showed a current density ∼30 times higher than without any α-NPD layer. However, the current density decreased as the α-NPD thickness increased beyond 5 nm. In contrast to the current density, the device efficiency improved as α-NPD layer thickness increased to 30 nm, after which a drop in efficiency was observed. The current efficiency of the device with 30 nm α-NPD thickness was 10 times higher than the device with 5 nm α-NPD thickness. The results indicated that hole-injection in OLEDs was more efficient with thin 5 nm α-NPD, while optimal efficiency was at 30 nm of α-NPD thickness.

Modelling of Germanium-Based Perovskite Solar Cell for Different Hole Transport Materials and Defect Density

The performance of four distinct materials (organic and inorganic) was simulated and analyzed as hole transport layer (HTL) in the design of germanium (Ge)-based Perovskite Solar Cell (PSC). A 1-dimensional numerical software (SCAPS 1-D) has been applied to simulate the HTL candidates: spiro-OMeTAD, PTAA, nickel oxide (NiO), and copper (I) thiocyanate (CuSCN), with tin (IV) dioxide (SnO2) as the electron transport layer (ETL). The thickness of the methylammonium germanium iodide (CH3NH3GeI3) absorber was varied from 300 nm to 1100 nm, and the highest simulated power conversion efficiency was achieved at a thickness of 800 nm for all HTL candidates. It was observed that the inorganic CuSCN outperformed its counterparts with a power conversion efficiency (PCE) of 25.38%. The effect of the perovskite absorber’s defect density was investigated, and ultimately, it was demonstrated that this value is disproportionately related to the PCE. A reduction of nearly 98% in PCE was recorded when the defect density increased from 1x1014 cm-3 to 1x1020 cm-3. Additionally, for a constant ETL thickness of 80 nm, it was revealed that the PCE would decrease slightly, ranging from 0.1% to 0.3%, with an increase in HTL thickness from 50 nm to 300 nm. Comparing the PCE of our current work with published reports further justifies its competitiveness. Full Text: PDF References W.R. Becquerel, "Becquerel Photovoltaic Effect in Binary Compounds", J. Chem. Phys. 32, 1505 (1960). CrossRef A. Kojima, K. Teshima, Y. Shirai, T. Miyasaka, "Organometal Halide Perovskites as Visible-Light Sensitizers for Photovoltaic Cells", J. Am. Chem. Soc. 131, 6050 (2009). CrossRef M.M. Salah, K.M. Hassan, M. Abouelatta, A. Shaker, "A comparative study of different ETMs in perovskite solar cell with inorganic copper iodide as HTM", Optik 178, 958 (2019). CrossRef S. Rai, B. Pandey, A. Garg, D. Dwivedi, "Hole transporting layer optimization for an efficient lead-free double perovskite solar cell by numerical simulation", Opt. Mater, 121, 111645 (2021). CrossRef H. Liangsheng, Z. Min, S. Yubao, M. Xinxia, W. Jiang, Z. Qunzhi, F, Zaiguo, L. Yihao, H. Guoyu, L. Tong, "Tin-based perovskite solar cells: Further improve the performance of the electron transport layer-free structure by device simulation", Sol. Energy, 230, 345 (2021). CrossRef K. Fatema, M. Arefin, "Enhancing the efficiency of Pb-based and Sn-based perovskite solar cell by applying different ETL and HTL using SCAPS-ID", Opt. Mater. 125, 112036 (2022). CrossRef P. Patel, "Device simulation of highly efficient eco-friendly CH3NH3SnI3 perovskite solar cell", Sci. Rep., 11, 3082 (2021). CrossRef P. Roy, Y. Raoui, A. Khare, "Design and simulation of efficient tin based perovskite solar cells through optimization of selective layers: Theoretical insights", Opt. Mater., 125, 112057 (2022). CrossRef A.I. Azmi, M.Y. Mohd Noor, M.H.I. Ibrahim, F. Ahmad, M.H. Ibrahim, "A Numerical Simulation of Transport Layer Thickness Effect in Tin-Based Perovskite Solar Cell", JJEE, 8, 355 (2022). CrossRef A.A. Kanoun, M.B. Kanoun, A.E. Merad, S. Goumri-Said, "Toward development of high-performance perovskite solar cells based on CH3NH3GeI3 using computational approach", Sol. Energy, 182, 237 (2019). CrossRef A. Hima, N. Lakhdar, "Enhancement of efficiency and stability of CH3NH3GeI3 solar cells with CuSbS2", Opt. Mater., 99, 109607 (2020). CrossRef S.T. Jan, M. Noman, "Influence of layer thickness, defect density, doping concentration, interface defects, work function, working temperature and reflecting coating on lead-free perovskite solar cell", Sol. Energy, 237, 29 (2022). CrossRef

Exploring and optimizing the performance of inorganic Cs2TiBr6 halide perovskite solar cell with Cu2ZnSnS4 as hole transport layer by device simulation

To seek appropriate substitutes for lead-based perovskite, a perovskite solar cell (PSC) model using Cu2ZnSnS4 as the hole transport layer (HTL) and Cs2TiBr6 as the absorber layer is proposed in this study. The focus of this study is to discuss the drift and diffusion ability of charge carriers in the n-i-p structure formed by ZnO/Cs2TiBr6/Cu2ZnSnS4 under the action of the built-in electric field and concentration gradient. And based on the data simulated by SCAPS-1D, the effects of bandgap structure and device structure on carrier mobility, carrier lifetime, carrier diffusion length, improvement of device performance of the device were further explored. In addition, the effects of HTL types, thickness of HTL, absorber, and ETL, and defect density of absorber on device structure and behavior were analyzed through simulation by SCAPS-1D. The theoretical calculation results obtained by optimizing the structural parameters include 29.24% power conversion efficiency (PCE), 1.22 V open circuit voltage (V oc ), 26.79 mA cm−2 short circuit current (J sc ) and 89.78% fill factor (FF). The conclusion that the n-i-p structure formed by ZnO/Cs2TiBr6/Cu2ZnSnS4 is conducive to carrier migration is vindicated in this study, which enables devices to possess better performance. This study provides a theoretical basis for the application of Cu2ZnSnS4 in inorganic halide-based PSCs.

Optimization and Efficiency Enhancement of Modified Polymer Solar Cells.

In this study, an organic bulk heterojunction (BHJ) solar cell with a spiro OMeTAD as a hole transport layer (HTL) and a PDINO as an electron transport layer (ETL) was simulated through the one-dimensional solar capacitance simulator (SCAPS-1D) software to examine the performance of this type of organic polymer thin-film solar cell. As an active layer, a blend of polymer donor PBDB-T and non-fullerene acceptor ITIC-OE was used. Numerical simulation was performed by varying the thickness of the HTL and the active layer. Firstly, the HTL layer thickness was optimized to 50 nm; after that, the active-layer thickness was varied up to 80 nm. The results of these simulations demonstrated that the HTL thickness has rather little impact on efficiency while the active-layer thickness improves efficiency significantly. The temperature effect on the performance of the solar cells was considered by simulations performed for temperatures from 300 to 400 K; the efficiency of the solar cell decreased with increasing temperature. Generally, polymer films are usually full of traps and defects; the density of the defect (Nt) value was also introduced to the simulation, and it was confirmed that with the increase in defect density (Nt), the efficiency of the solar cell decreases. After thickness, temperature and defect density optimization, a reflective coating was also applied to the cell. It turned out that by introducing the reflective coating to the back side of the solar cell, the efficiency increased by 2.5%. Additionally, the positive effects of HTL and ETL doping on the efficiency of this type of solar cells were demonstrated.

Simulation of Lead-Free Heterojunction CsGeI2Br/CsGeI3-Based Perovskite Solar Cell Using SCAPS-1D

This paper presents the simulation of the novel prototype of a heterojunction perovskite solar cell (PSC) based on CSGeI2Br/CSGeI3. The device consists of two absorber layers (CSGeI2Br, CSGeI3), an electron transport layer (ETL) chosen as TiO2 and a hole transport layer (HTL) given as poly(3-hexylthiophene) (P3HT). Within the simulation, the effects of thickness, doping and defect density in each absorber layer and different back contact metal electrodes on electrical parameters (efficiency, short circuit current, open circuit voltage, and fill factor) are evaluated. In addition, the contribution of the HTL (doping density and thickness), temperature, shunt and series resistance were also checked on the same electrical parameters. The simulations are conducted in standard test conditions with the irradiation normalized as 0.1 W/cm2 using the SCAPS-1D platform. The maximum efficiency obtained within the simulation of this device was about 31.86%. For this device, the thickness of the CSGeI3 layer should be around 900 nm, while that of the CsGeI2Br should be around 100 nm to facilitate optimal absorption of the incident photons. The doping density in the absorber layer is such that in CsGeI3 should be around 1018 cm−3 and around 1016 cm−3 in the CsGeI2Brlayer. The defects densities in both layers of the perovskite materials should be around 1014 cm−3. Concerning the HTL, the thickness and the doping density of the P3HT should be around 50 nm and 1018 cm−3, respectively. In terms of the back contact electrode, the work function of the metal should be at least equal to 5 eV, corresponding to gold (Au) metal. The series resistance due to the connection of the cell to the external load should be very small, while the shunt resistance due to the leakage current in the solar cell should be high. Furthermore, the operating temperature of the new PSC should be maintained at an ambient level of around 25 °C in order to deliver high efficiency.

Impact of tin-based perovskite as a hole transport layer on the device performance of stable and 27.10% efficient CdTe-based solar cell by numerical simulation

In this work, a numerical simulation study on cadmium telluride (CdTe)-based thin film solar cell structure utilizing CdTe as absorber layer, Cadmium sulphide (CdS) as window layer, and lead-free perovskite (CH3NH3SnBr3) as a hole transport layer (HTL) is presented for the first time. The effect of different material parameters such as shallow uniform acceptor density (NA) of absorber and HTL, thicknesses of absorber and HTL, Electron affinity of HTL, defect density of absorber layer, series and shunt resistance, back contact metal work function, and operating temperature on photovoltaic (PV) parameters such as open-circuit voltage (Voc), short circuit current (Jsc), fill factor (FF), and photo conversion efficiency (PCE) has been studied. With the introduction of perovskite as HTL, it is observed that Voc increased from 0.66 V to 1.17 V by creating a suitable band alignment with the CdTe absorber layer, causing an improvement in efficiency by preventing carrier recombination at the back contact surface. The designed solar cell has shown an enhanced PCE of 27.10% with Voc ∼1.17 V, Jsc ∼27.76 mA/cm2, and FF ∼83.40%. Thus, from the study, it is possible to achieve high-performance CdTe-based solar cells using perovskite as HTL for photovoltaic applications.

Deep Insights into the Coupled Optoelectronic and Photovoltaic Analysis of Lead-Free CsSnI3 Perovskite-Based Solar Cell Using DFT Calculations and SCAPS-1D Simulations.

CsSnI3 is considered to be a viable alternative to lead (Pb)-based perovskite solar cells (PSCs) due to its suitable optoelectronic properties. The photovoltaic (PV) potential of CsSnI3 has not yet been fully explored due to its inherent difficulties in realizing defect-free device construction owing to the nonoptimized alignment of the electron transport layer (ETL), hole transport layer (HTL), efficient device architecture, and stability issues. In this work, initially, the structural, optical, and electronic properties of the CsSnI3 perovskite absorber layer were evaluated using the CASTEP program within the framework of the density functional theory (DFT) approach. The band structure analysis revealed that CsSnI3 is a direct band gap semiconductor with a band gap of 0.95 eV, whose band edges are dominated by Sn 5s/5p electrons After performing the DFT analysis, we investigated the PV performance of a variety of CsSnI3-based solar cell configurations utilizing a one-dimensional solar cell capacitance simulator (SCAPS-1D) with different competent ETLs such as IGZO, WS2, CeO2, TiO2, ZnO, PCBM, and C60. Simulation results revealed that the device architecture comprising ITO/ETL/CsSnI3/CuI/Au exhibited better photoconversion efficiency among more than 70 different configurations. The effect of the variation in the absorber, ETL, and HTL thickness on PV performance was analyzed for the above-mentioned configuration thoroughly. Additionally, the impact of series and shunt resistance, operating temperature, capacitance, Mott-Schottky, generation, and recombination rate on the six superior configurations were evaluated. The J-V characteristics and the quantum efficiency plots for these devices are systematically investigated for in-depth analysis. Consequently, this extensive simulation with validation results established the true potential of CsSnI3 absorber with suitable ETLs including ZnO, IGZO, WS2, PCBM, CeO2, and C60 ETLs and CuI as HTL, paving a constructive research path for the photovoltaic industry to fabricate cost-effective, high-efficiency, and nontoxic CsSnI3 PSCs.

A comprehensive study on RbGeI3 based inorganic perovskite solar cell using green synthesized CuCrO2 as hole conductor

Though perovskite solar cell (PSC) is achieving an immense 25.7 % efficiency within a few years of extensive research, a shorter life span with organic part and charge transporting layers hinders their commercialization. So, inorganic perovskite aligned with the hole transporting layer (HTL) could be an alternative to achieve long-term device stability. The delafossite, CuCrO2 was prepared by the green synthesized method and then characterized. According to the X-ray diffraction (XRD) pattern, the crystallites are polycrystalline phases, and the average crystallite size is 159.3 nm. Spectrophotometric measurement was used to determine the bandgap (Eg), which is 3.0 eV. These results are applied for simulation study in Pb-free RbGeI3-based inorganic perovskite device using CuCrO2 as HTL. HTL thickness, diffusion length, interface defect, carrier concentration, activation energy, and temperature effects on the device performance have been explored by SCAPS-1D simulation software. In the optimized condition, the simulated result shows the maximum device efficiency is 23.8 %, corresponding open circuit voltage (Voc), short circuit current density (Jsc) and fill-factor (FF) of 0.89 V, 33.7 mA cm−2, and 79.2 %, respectively. A study of activation energy for the device elucidates that the significant recombination is Shockley Read Hall (SRH) type at the (RbGeI3/CuCrO2) interface layer. The result of temperature impact has supported better thermal stability. Indium tin oxide (ITO) is suitable front contact for the proposed p-i-n structure. The study reveals that the delafossite, CuCrO2 can be a potential HTL for Pb-free inorganic perovskite solar cells.

Theoretical Performance Analysis of Inverted P3HT: PCBM Based Bulk Hetero-Junction Organic Solar Cells through Simulation

In this study, the role of active layer thickness, hole transport layer thickness, and electron mobility on the performance of P3HT: PCBM-based inverted organic solar cells has been investigated. The simulation has been done for device structure ITO/ZnO/P3HT: PCBM/MoO3/Ag using the general-purpose photovoltaic device model (GPVDM) program tool. The short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE) of the cell were determined by varying the thickness of the active layer from 140 nm to 260 nm, the hole transparent layer from 10 nm to 40 nm, and electron mobility from 0.5 × 10−3 cm2V−1s−1 to 6.5 × 10−3 cm2V−1s−1. The PCE improvement was observed at 220 nm and 20 nm active layer and hole transporting layer thickness, respectively, for 4.5 × 10−3 cm2V−1s−1 electron mobility. The results confirmed that the thickness of the active layer, hole transport layer, and charge carrier mobility plays an important role in the performance improvement of organic solar cells.

Decorated pyridine as hole transporting material (HTM) for solution-processed OLEDs

While organic light emitting diodes (OLEDs) technology is evolving at a fast pace, the development of flexible and full-color display panels with low power consumption provides superiority to these devices as eco-friendly lighting sources. Several strategies and methods have been attempted to improve the OLED device performance, especially in light-emitting materials. Even though, with significant advancements in efficiency, OLED technology demonstrates the feasibility to enhance further without saturation, thus attracting researchers to develop new materials with an effective device strategy. In this work, we report an integrated hole transporting material, 3,6-bis(4,6-diphenylpyridin-2-yl)-9-ethyl-9H-carbazole (CDP) with functionalization of carbazole unit with pyridine substituents. CDP adopted a moderately high triplet energy (2.61 eV), high thermal stability, and high hole transportability. Solution-processed CDP-based OLEDs were fabricated containing phosphorescent green emitter (Ir(PPy)3) and compared with conventional N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) based OLEDs. The CDP-based device exhibited a high performance with decreased layer thickness from ∼25 nm to ∼5 nm, with maximum external quantum efficiency, power efficiency, current efficiency, and brightness of 17.2 %, 66.8 lm/W, 64.0 cd/A, and 18,740 cd/m2, respectively which was superior to the NPB-based control device. Enhancement in device performance with reduced thickness of hole transport layer in CDP-based OLEDs distinctly demonstrates the effective potential of the designed material.

Optimization of tin based perovskite solar cell employing CuSbS2 as HTL: A numerical simulation approach

The expeditious progresses in the domain of organo-metallic halide perovskite solar cells has resulted in PCE of more than 25.5%. However, their extensive utilization and fully fledged commercialization is currently restricted owing to the existence of expensive hole transport layer (HTL) viz Spiro-OmeTAD in the novel devices. In this paper, a low cost and easily available materials i.e. CuSbS2 and fullerene (C60) are endeavored as HTL and ETL respectively, by utilizing SCAPS 1D simulator, which can also yield high solar cell performance. In this context, the analysis of Spiro-OmeTAD, CuSbS2 as HTLs and TiO2, C60 as ETLs has been validated. In addition, effect of thickness of HTLs on perovskite solar cells using CH3NH3SnI3 as light harvester & C60 as hole inhibiting layer/electron transport layer (ETL) has been also examined. The recommended simulation reveals that using 20 nm of CuSbS2 layer can outperform Spiro-OmeTAD as HTL for cell fabrication. It has been observed that by employing proposed perovskite solar cell configuration FTO/C60/CH3NH3SnI3/CuSbS2/Au, an efficiency (PCE) of 26.05% associated with fill factor (FF) of 82.98%, short circuit current (Jsc) of 31.646 mA/cm2 & open circuit voltage (Voc) of 0.9918 V can be yielded which assures exhibition of better solar cell performance than the existing solar cell.

Efficiency enhancement of triple absorber layer perovskite solar cells with the best materials for electron and hole transport layers: numerical study

In this paper, a novel perovskite solar cell (PSC) with a triple absorber layer is numerically simulated using Solar Cell Capacitance One-Dimensional software. The initial simulation of the structure (FTO/TiO2/CsSnI3/CsSnGeI3/Cs3Sb2Br9/spiro-OMeTAD/Au) reveals that by combining cesium tin triiodide (CsSnI3), cesium tin-germanium triiodide (CsSnGeI3) and cesium antimony bromide (Cs3Sb2Br9) as triple absorber layer, we obtain a higher efficiency (31.81%) than the single (CsSnI3), and double (CsSnI3/CsSnGeI3) layer structures, whose efficiencies are 12.87% and 29.41%, respectively. Then, to optimize the proposed structure, different parameters like; thicknesses of the triple absorber layer, different materials of electron transport layer (ETL) and hole transport layer (HTL), thicknesses of ETL and HTL, as well as the operating temperature have been investigated. The optimized structure (0.4/0.1/0.1 µm of CsSnI3/CsSnGeI3/Cs3Sb2Br9 as triple absorber layer; 0.1 µm of tungsten trioxide WO3 as ETL and 0.35 µm of copper(I) oxide Cu2O as HTL, as well as an optimum temperature of 300 K) shows a remarkable photovoltaic parameters i.e. J SC = 32.640 774 mA cm−2, V OC= 1.2442 V, FF = 89.17% and η = 36.21% (which corresponds to an improvement of 4.4% compared to the initial proposed structure (31.81%)). This study’s simulation results open a better route toward fabricating highly efficient PSCs.

Numerical Evaluation of Novel Bio‐Photovoltaic Devices Inspired by Photosynthetic Process and High Poly (3,4‐Ethylenedioxythiophene): Poly (styrenesulfonate) Efficacy as Hole Transport Layer

Organic‐based photosystem I (PSI) protein complex bio‐solar cells have appeared as strong candidates for very low‐cost and environmentally friendly photovoltaic devices. The main challenge is their low power conversion efficiency (PCE). Such bottleneck stage in efficiency could be improved from the aspects of the absorber layer and carrier transporting layers. The proposed efficient, eco‐friendly, and simple procedure by applying a uniform pulsed electric field to align PSI dipoles leads to improved significant efficiency. Herein, the experimentally found functional data to benchmark cells have been employed to validate the first PSI numerical model using solar cell capacitance simulator‐1D for the first time. Simulation results show a reasonable agreement with those of experimental. The performance response of the second indium tin oxide/PEDOT: PSS/PSI/Au model is evaluated by varying the physical parameters of the hole transport layer (HTL). PCE characteristic achieved a fourfold increment in the crucial conduction band offset region owing to the reasonable barrier formation of electrons in the HTL/absorber interface. The optimum doping concentration is authorized at a certain μp > 10−2 cm2 V−1 S−1 with an HTL thickness in the order of 102 nm estimating an efficient numerical model compared to the HTL‐free cell.

Oxidized Nickel to Prepare an Inorganic Hole Transport Layer for High-Efficiency and Stability of CH3NH3PbI3 Perovskite Solar Cells

In this study, we report a perovskite solar cell (PSC) can be benefited from the high quality of inorganic nickel oxide (NiOx) as a hole transport layer (HTL) film fabricated from the physical vapor deposition (PVD) process. The power conversion efficiency (PCE) of PSC is found to depend on the thickness of NiOx HTL. The NiOx thickness is optimized via quantitative investigation of the structure, optical and electrical properties. With an active area of 11.25 cm2, a PSC module (25 cm2) with a PCE of 15.1% is demonstrated, while statistically averaged PCE = 18.30% with an open voltage (Voc) 1.05 V, short-circuit current density (Jsc) 23.89 mA/cm2, and fill factor (FF) 72.87% can be achieved from 36 devices with smaller active areas of 0.16 cm2. After the stability test at 40% relative humidity (RH) and 25 °C for 1200 h, the highest performance NiOx-based PSC is shown to be about 1.2–1.8 times superior to PEDOT:PSS organic HTL based PSC at the same environment.