Inverted Planar Perovskite Solar Cells Research Articles

Enhancing performance of low-temperature fabricated inverted planar perovskite solar cells through triple-cation perovskite optimization

Perovskite solar cells have garnered significant attention due to the rapidly advancing power conversion efficiency(PCE). Recently, there has been significant interest in enhancing the performance of perovskite solar cells through Cs+ doping. However, the optimal concentration of Cs+ varies between inverted and positive structures, influenced by factors such as cell design, fabrication processes, and performance optimization requirements. In this study, we designed and prepared a novel inverted structure triple cations FA/MA/Cs perovskite solar cell at a low temperature. We observed that the quality of perovskite films can be obviously improved by doping an appropriate amount of Cs+, but excessive Cs+ will destabilize the perovskite structure, leading to rapid film decomposition in ambient air. Our results indicate that employing higher concentrations of Cs+, specifically 10 % and 15 %, leads to superior performance and enhanced stability. Notably, the perovskite solar cell incorporating 10%-Cs exhibits larger grain sizes, uniform particle distribution, and its highest PCE achieves 16.41 %. Our research provides a straightforward and cost-effective strategy for improving the performance of inverted perovskite solar cells utilizing triple cations.

Analysis of Inverted Planar Perovskite Solar Cells with Graphene Oxide as HTL using L9 OA Taguchi Method

In this work, the Taguchi Method approach is used to optimize graphene oxide (GO) as the hole transport layer (HTL) in inverted perovskite solar cells (IPSC). By using this method, the data from the numerical modelling Solar Cell Capacitance Simulator-One Dimensional (SCAPS-1D) was optimized. While it has distinct parameter results and diverse causes, it also takes a long time to complete the analysis process. The Taguchi method is reported to be able to find the most significant factor and reduce the parameter variations in less time. The Taguchi algorithm is used in this experiment because it is based on orthogonal array (OA) experiments, which provide a substantially smaller variance for the experiment with optimal control parameter values. SCAPS-1D software was used to simulate the IPSC with GO as HTL. The results obtained with the software are then analysed and compared with the performance of the solar cell. The final results show that the Taguchi Method optimized IPSC with GO as HTL achieved better Power Conversion Efficiency (PCE) compared to previous researchers, with the efficiency increasing from 18.53%.to 23.408%.

Halogen doping of p-type inorganic hole transport layer: electronic nature-based dopant engineering for modulating hole selectivity in inverted planar perovskite solar cells

The role of metal cation and halide anion dopants in regulating the properties of NiOx hole transport layer (HTL) was explored. This study confirms that halide dopants also increase the Ni3+ defect density and work function of p-type inorganic HTL.

High performance inverted planar perovskite solar cells enhanced by heteroatomic functionalized hole transport materials

Two heteroatomic functionalized hole transport materials with the rhodanine group have been developed, and the PSC devices with a high-quality perovskite layer and excellent interfacial contacts are fabricated, resulting in a champion PCE of 21.5%.

Enhancing electron transport through metal oxide adjustments in perovskite solar cells and their suitability for X-ray detection

Inverted planar perovskite solar cells with PCBM ETL have poor film formation and charge transfer. Adding MgO improves photoluminescence, carrier lifetime, and efficiency to 15.12%, and enhances X-ray detector performance.

Electrosynthesis of buckyballs with fused-ring systems from PCBM and its analogue

[6,6]-Phenyl-C61-butyric acid methyl ester (PCBM), a star molecule in the fullerene field, has found wide applications in materials science. Herein, electrosynthesis of buckyballs with fused-ring systems has been achieved through radical α-C−H functionalization of the side-chain ester for both PCBM and its analogue, [6,6]-phenyl-C61-propionic acid methyl ester (PCPM), in the presence of a trace amount of oxygen. Two classes of buckyballs with fused bi- and tricyclic carbocycles have been electrochemically synthesized. Furthermore, an unknown type of a bisfulleroid with two tethered [6,6]-open orifices can also be efficiently generated from PCPM. All three types of products have been confirmed by single-crystal X-ray crystallography. A representative intramolecularly annulated isomer of PCBM has been applied as an additive to inverted planar perovskite solar cells and boosted a significant enhancement of power conversion efficiency from 15.83% to 17.67%.

Realization of High-Efficiency Inverted Planar Perovskite Solar Cells Based on PEDOT: PSS Doped with Lithium Fluoride

The photovoltaic performance of perovskite solar cells with inverted structure depends on the conductivity of the hole transport layer and the charge transport rate to some extent. To further enhance the effect of the hole transport layer, lithium fluoride (LiF) was doped into poly (3,4-ethylene dioxythiophene)-polystyrene sulfonic acid (PEDOT: PSS) to improve its rate of conductivity and interfacial charge transport. The optimal photoelectric conversion efficiency of LiF-based perovskite solar cells that dope hole transport layer is 20.32% with negligible hysteresis, which is much higher than that of the control group (16.70%). Among all photovoltaic parameters, the improvement of open circuit voltage and fill factor is significant. LiF can not only promote the electrical characteristics of PEDOT: PSS and its hole mobility, but also optimize the quality of the upper perovskite film. Perovskite film shows a crystal orientation more conducive to hole transport on the modified hole transport layer, which obtains a dense and smooth absorption layer film. In this study, PEDOT: PSS-based perovskite solar cells with inverted structure doped with LiF are prepared, which provides a simple and effective method to commercialize perovskite solar cells.

Optimizing the Performance of Sputtered‐NiOx‐Based Perovskite Solar Cells via Regulating the PbI2 Concentration

Nickel oxide (NiOx) prepared by sputtering is a promising hole transport material for inverted planar perovskite solar cells (PSCs) because of its wide bandgap, deep valance band edge, excellent optical transmittance, and low cost. However, the interface reaction between sputtered‐NiOx and perovskite layer leads to the formation of lead iodine on perovskite surface, which limits the efficiency and stability of the device. Herein, we report a facile approach to improve the performance of the sputtered‐NiOx‐based PSCs via precise control the concentration of PbI2 in precursor solution. It is demonstrated that the concentration of PbI2 has a significant effect on the microstructure and photoelectric properties of the perovskite layer deposited on sputtered‐NiOx. When the PbI2 concentration is 2% less than the stoichiometric perovskite, the efficiency of the optimized device is improved to 15.64%, and the device stability under unencapsulated atmospheric conditions is also significantly improved. In the optimized sample, a small amount of residual PbI2 still exists in perovskite films, which is proved beneficial for passivating grain boundary defects and enhancing the performance of the PSCs. This work provides a feasible way for enhancing the performance of sputtered‐NiOx‐based PSCs as well suggest a probability for reducing the consumption of PbI2.

Novel Spiro-Core Dopant-Free Hole Transporting Material for Planar Inverted Perovskite Solar Cells.

Hole-transporting materials (HTMs) have demonstrated their crucial role in promoting charge extraction, interface recombination, and device stability in perovskite solar cells (PSCs). Herein, we present the synthesis of a novel dopant-free spiro-type fluorine core-based HTM with four ethoxytriisopropylsilane groups (Syl-SC) for inverted planar perovskite solar cells (iPSCs). The thickness of the Syl-SC influences the performance of iPSCs. The best-performing iPSC is achieved with a 0.8 mg/mL Syl-SC solution (ca. 15 nm thick) and exhibits a power conversion efficiency (PCE) of 15.77%, with Jsc = 20.00 mA/cm2, Voc = 1.006 V, and FF = 80.10%. As compared to devices based on PEDOT:PSS, the iPSCs based on Syl-SC exhibit a higher Voc, leading to a higher PCE. Additionally, it has been found that Syl-SC can more effectively suppress charge interfacial recombination in comparison to PEDOT:PSS, which results in an improvement in fill factor. Therefore, Syl-SC, a facilely processed and efficient hole-transporting material, presents a promising cost-effective alternative for inverted perovskite solar cells.

Enhancing Planar Inverted Perovskite Solar Cells with Innovative Dumbbell‐Shaped HTMs: A Study of Hexabenzocoronene and Pyrene‐BODIPY‐Triarylamine Derivatives

AbstractDumbbell‐shaped systems based on PAHs‐BODIPY‐triarylamine hybrids TM‐(01‐04) are designed as novel and highly efficient hole‐transporting materials for usage in planar inverted perovskite solar cells. BODIPY is employed as a bridge between the PAH units, and the effects of the conjugated π‐system's covalent attachment and size are investigated. Fluorescence quenching, 3D fluorescence heat maps, and theoretical studies support energy transfer within the moieties. The systems are extremely resistant to UVC 254 nm germicidal light sources and present remarkable thermal stability at degradation temperatures exceeding 350 °C. Integrating these systems into perovskite solar cells results in outstanding power conversion efficiency (PCE), with TM‐02‐based devices exhibiting a PCE of 20.26%. The devices base on TM‐01, TM‐03, and TM‐04 achieve PCE values of 16.98%, 17.58%, and 18.80%, respectively. The long‐term stability of these devices is measured for 600 h, with initial efficiency retention between 94% and 86%. The TM‐04‐based device presents noticeable stability of 94%, better than the reference polymer PTAA with 91%. These findings highlight the exciting potential of dumbbell‐shaped systems based on PAHs‐BODIPY‐triarylamine derivatives for next‐generation photovoltaics.

Low-Temperature Aqueous Ammonia-Processed Copper (I) Selenocyanate Hole-Transporting Material for Efficient Inverted Perovskite Solar Cells

Significant efforts have been reported on copper(I) thiocyanate (CuSCN) as an efficient hole-transporting layer (HTL) for perovskite solar cells. Surprisingly, its higher chalcogen analogue copper (I) selenocyanate (CuSeCN) is unexplored yet, even though CuSeCN has been shown to have different properties compared to CuSCN because of its different electronegativity, polarizability, and size (Se vs S atoms). In this work, we report the synthesis of CuSeCN as an HTL in perovskite solar cells via low-temperature solution-processable deposition from an aqueous ammonia solution. The transparency and thermal stability of CuSeCN films were examined by the deposition of thin films from an aqueous ammonia solution under ambient conditions. The structural, electrical, optical, and morphological properties of the CuSeCN films were characterized by X-ray diffraction, XPS, FTIR, cyclic voltammetry, UV–vis–NIR spectroscopy, and field emission scanning electron microscopy. A single-step fast deposition–crystallization method was used to fabricate low-temperature CuSeCN-based inverted planar perovskite solar cells, with device architecture indium tin oxide (ITO)/CuSeCN/CH3NH3PbI3/PC61BM/BCP/Ag. Furthermore, to examine the effect of the thickness of the HTL on device performance, three different concentrations of CuSeCN solution were used for thin-film deposition in perovskite solar cells. The annealing temperature of the HTL films was optimized to obtain the highest possible device performance. A maximum power conversion efficiency (PCE) of 13.59% (Voc = 0.99 V, Jsc = 18.8 mA/cm2, and FF = 0.73) was achieved with 7.5 mg mL–1 of CuSeCN solution, along with negligible J–V hysteresis and reproducibility of device performance.

Fabrication of inverted planar perovskite solar cells using the iodine/ethanol solution method for copper iodide as a hole transport layer

Copper iodide (CuI) is under extensive research due to its low cost, easy fabrication process, and wide bandgap. This research includes the fabrication of perovskite solar cells using the p–i–n structure (inverted structure) with a focus on the hole transport layer (HTL) layer. In this paper, we demonstrate the applicability of using CuI as a HTL in perovskite solar cells using the iodine/ethanol solution method. Using the iodine/ethanol solution for preparing the CuI, a power conversion efficiency of 0.76%, a short-circuit current density of 4.56 mA cm−2, an open-circuit voltage of 0.494 V as well as a fill factor of 0.34 were obtained. The overall performance of the solar cell still requires much improvement. We have successfully deposited the CuI using RF magnetron sputtering and the iodine/ethanol solution method and understand that the low performance of the device is mainly due to the voids and gaps present within the CuI layer.

60]Fullerene-Fused Cyclopentanes: Mechanosynthesis and Photovoltaic Application

The mechanochemical cascade reaction of [60]fullerene with 3-benzylidene succinimides, diethyl 2-benzylidene succinate, or 2-benzylidene succinonitrile in the presence of an inorganic base has been investigated under solvent-free and ball-milling conditions. This protocol provides an expedient method to afford various [60]fullerene-fused cyclopentanes, showing advantages of good substrate scope, short reaction time, and solvent-free and ambient reaction conditions. Furthermore, representative fullerene products have been applied in inverted planar perovskite solar cells as efficient cathode interlayers.

Thermally Evaporated ZnSe for Efficient and Stable Regular/Inverted Perovskite Solar Cells by Enhanced Electron Extraction

Electron transport layers (ETLs) are crucial for achieving efficient and stable planar perovskite solar cells (PSCs). Reports on versatile inorganic ETLs using a simple film fabrication method and applicability for both low‐cost planar regular and inverted PSCs with excellent efficiencies (>22%) and high stability are very limited. Herein, we employ a novel inorganic ZnSe as ETL for both regular and inverted PSCs to improve the efficiency and stability using a simple thermal evaporation method. The TiO2‐ZnSe‐FAPbI3 heterojunction could be formed, resulting in an improved charge collection and a decreased carrier recombination further proved through theoretical calculations. The optimized regular PSCs based on TiO2/ZnSe have achieved 23.25% efficiency with negligible hysteresis. In addition, the ZnSe ETL can also effectively replace the unstable bathocuproine (BCP) in inverted PSCs. Consequently, the ZnSe‐based inverted device realizes a champion efficiency of 22.54%. Moreover, the regular device comprising the TiO2/ZnSe layers retains 92% of its initial PCE after 10:00 h under 1 Sun continuous illumination and the inverted device comprising the C60/ZnSe layers maintains over 85% of its initial PCE at 85 °C for 10:00 h. This highlights one of the best results among universal ETLs in both regular and inverted perovskite photovoltaics.

Simulation and Investigation of 26% Efficient and Robust Inverted Planar Perovskite Solar Cells Based on GA0.2FA0.78SnI3-1%EDAI2 Films.

A hybrid tin-based perovskite solar cell with p-i-n inverted structure is modeled and simulated using SCAPS. The inverted structure is composed of PEDOT:PSS (as hole transport layer-HTL)/GA0.2FA0.78SnI3-1% EDAI2 (as perovskite absorber layer)/C60-fullerene (as electron transport layer-ETL). Previous experimental studies showed that unlike conventional tin-based perovskite solar cells (PSC), the present hybrid tin-based PSC passes all harsh standard tests and generates a power conversion efficiency of only 8.3%. Despite the high stability that this material exhibits, emphasis on enhancing its power conversion efficiency (PCE) is crucial. To that end, various ETL and HTL materials have been rigorously investigated. The impact of energy level alignment between HTL/absorber and absorber/ETL interfaces have been elucidated. Moreover, the thickness and the doping concentration of all the previously mentioned layers have been varied to inspect their effect on the photovoltaic performance of the PSC. The optimized structure with CuI (copper iodide) as HTL and ZnOS (zinc oxysulphide) as ETL scored a PCE of 26%, which is more than three times greater than the efficiency of the initial structure. The current numerical simulation on GA0.2FA0.78SnI3-1% EDAI2 could greatly increase its chance for commercial development.

Na2S decorated NiOx as effective hole transport layer for inverted planar perovskite solar cells

NiOx have been considered as an excellent material for hole transport layer (HTL) of perovskite solar cells because of its wide band gap, excellent optical transmittance, proper chemical stability and energy level matching with perovskite materials. However, the power conversion efficiency (PCE) of inverted perovskite solar cells (PSCs) is hindered by the low conductivity of unmodified NiOx. Here, we reported an operative Na2S treated NiOx HTL, which could optimize the conductivity of the NiOx layers and the crystallinity of perovskite. The synergistic effect of Na cations and S anions could strengthen the conductivity of the NiOx HTL, improve the interface contact between NiOx and perovskite, and enhance the quality of the perovskite film, so as to boost photoelectricity performance of the device. The carrier dynamics have shown that doping of Na2S could not only diminish the interface defects of the HTL/perovskite layer, but also improve the hole extraction at the NiOx/perovskite interface. All these factors led to the improvements in short-circuit density (Jsc), fill factor (FF) and PCE of inverted planar perovskite solar cells. Consequently, Na2S-decorated NiOx HTL contributes to a stable device which attains a champion efficiency of 16.9%.

Development and analysis of rGO-MoS2 nanocomposite as top electrode for the application of inverted planar perovskite solar cells via SCAPS-1D device simulation

Development and analysis of rGO-MoS2 nanocomposite as top electrode for the application of inverted planar perovskite solar cells via SCAPS-1D device simulation

Crack‐Free Monolayer Graphene Interlayer for Improving Perovskite Crystallinity and Energy Level Alignment in Efficient Inverted Perovskite Solar Cells

Inverted planar perovskite solar cells (PSCs) have intrigued great promise in negative hysteresis, simple fabrication process, and flexible substrate implementation, in which the shared hole transport materiel is NiOx. However, the low‐temperature solution processing of the NiOx film is usually accompanied by defect formation, which deteriorates the perovskite quality and device performance. Meanwhile, the energy‐level offset between the NiOx and perovskite films is relatively large, limiting the interfacial charge transport. To suppress those setbacks, a defect‐free monolayer graphene sheet is transferred onto the NiOx film surface as a template for van der Waals epitaxial growth of perovskite films for the first time, leading to enhancing crystallinity with a large grain size of perovskite layer, 0.20 eV energy level offset drop, and accelerating charge transfer for the devices. Finally, the power conversion efficiency of 19.21% without hysteresis is achieved, exceeding 18.35% of the control device.

Coevaporation of Doped Inorganic Carrier‐Selective Layers for High‐Performance Inverted Planar Perovskite Solar Cells

Inorganic carrier‐selective layers (CSLs), whose conductivity can be effectively tuned by doping, offer low‐cost and stable alternatives for their organic counterparts in perovskite solar cells (PSCs). Herein, a dual‐source electron‐beam co‐evaporation method for the controlled deposition of copper‐doped nickel oxide (Cu:NiO) and tungsten‐doped niobium oxide (W:Nb2O5) as hole and electron transport layers, respectively, is used. The mechanisms for the improved conductivity using dopants are investigated. Owing to the improved conductivity and optimized band alignment of the doped CSLs, the all‐inorganic‐CSLs‐based PSCs achieve a maximum power conversion efficiency (PCE) of 20.47%. Furthermore, a thin titanium buffer layer is inserted between W:Nb2O5 and the silver electrode to prevent halide ingression and improve band alignment. This leads to a further improvement of PCE to 21.32% and long‐term stability (1200 h) after encapsulation. Finally, the large‐scale applicability of the doped CSLs by coevaporation is demonstrated for the device with 1 cm2 area showing a PCE of over 19%. The results demonstrate the potential application of the coevaporated CSLs with controlled doping in PSCs for commercialization.

Optimization of inverted planar perovskite solar cells with environment-friendly MAPb0.25Ge0.75I3 absorber approaching Shockley Queisser limit for efficiency

The search for an environmentally benign substitution of toxic lead (Pb) in MAPbI3 –based perovskite solar cells has so far resulted in a compromised performance like poorer efficiency, which is more pronounced in inverted planar (p-i-n) structure. A few theoretical studies have revealed that mixed cation perovskites with low Pb-content, MAGe0.75Pb0.25I3, can have an optical bandgap between 1.33 and 1.41 eV, a bandgap range that can attain maximum efficiency indicated by Shockley Quiesser (SQ) limit. With the motivation of finding an environmental friendly as well as high performing perovskite solar cells, an inverted planar cell configuration is simulated utilizing MAGe0.75Pb0.25I3 as the absorber with commonly used transport layers. The simulation model is optimized based on MAGe0.75Pb0.25I3 material parameters (bandgap, Eg and electron affinity, χ) and film properties (thickness, bulk, and interface defect densities). It is observed that landmark efficiency over 30% is obtainable with Eg = 1.4eV at typical film thicknesses of 500–600 nm with absorber bulk defect density 1014 cm−3 and interface recombination velocity 100 cms−1. Moreover, the cell displays significant efficiency of 20–24% even at higher defect densities, emulating degraded absorber film quality. Thus from the comprehensive study presented here, it is quite evident that MAGe0.75Pb0.25I3 indicates a pathway to approach the SQ limit in terms of efficiency for perovskite solar cells.