Power Conversion Efficiency Of Device Research Articles

Praseodymium doped nickel oxide as hole-transport layer for efficient planar Perovskite Solar Cells

Hybrid organic/inorganic perovskite solar cells (PSCs) have acquired significant consideration due to high power conversion efficiency (PCE). In PSCs, electron and hole extraction layers have a significant influence on their overall performance. In inverted p-i-n structure-based PSCs, NiOx has been frequently employed as a hole transport layer (HTL) due to its simple processing, wide bandgap, high optical transmittance, excellent chemical stability, and low processing temperature for large-scale fabrication. However, NiOx suffers from low electrical conductivity. Doping of NiOx is an effective technique employed for enhancing electrical as well as optical properties. Herein, the praseodymium doped NiOx (Pr-NiOx) was synthesized by sol-gel method, and films were fabricated to investigate the effect of Pr dopant on the optoelectronic properties and photovoltaic performance of PSCs. Results indicated that Pr doping significantly improved the hole mobility by about threefold and conductivity of NiOx films from 4.68 × 10-6 S cm-1 to 8.27 × 10-6 S cm-1. Moreover, it also enhanced the compactness and interfaces of NiOx HTL. PSCs based on 4 % Pr-doped NiOx HTL- yielded PCE of 9.35 % which is 32.43 % more than the PSCs fabricated using undoped NiOx HTL. The enhanced PCE of PSC devices with Pr-doped NiOx could be attributed to efficient extraction of a hole from an active absorbing layer of perovskite thereby, lowering the probability of unsuitable charge carrier recombination. This work exhibits that Pr-doped NiOx thin film could be a promising alternative material for efficient and stable inverted PSCs.

The Development of Carbon/Silicon Heterojunction Solar Cells through Interface Passivation.

Passivating contactsin heterojunction (HJ) solar cells have shown great potential in reducing recombination losses, and thereby achieving high power conversion efficiencies in photovoltaic devices. In this direction, carbon nanomaterials have emerged as a promising option for carbon/silicon (C/Si) HJsolar cells due to their tunable band structure, wide spectral absorption, high carrier mobility, and properties such as multiple exciton generation. However, the current limitations in efficiency and active area have hindered the industrialization of these devices. In this review, they examine the progress made in overcoming these constraints and discuss the prospect of achieving high power conversion efficiency (PCE) C/Si HJ devices. A C/Si HJ solar cell is also designed by introducing an innovative interface passivation strategy to further boost the PCE and accelerate the large area preparationof C/Si devices. The physical principle, device design scheme, and performanceoptimization approaches of this passivated C/Si HJ cells are discussed. Additionally, they outline potential future pathways and directions for C/Si HJ devices, including a reduction in their cost to manufacture and their incorporation intotandem solar cells. As such, this review aims to facilitate a deeperunderstanding of C/Si HJ solar cells and provide guidance for their further development.

Polymer-Doped SnO2 as an Electron Transport Layer for Highly Efficient and Stable Perovskite Solar Cells.

To produce highly efficient and repeatable perovskite solar cells (PSCs), comprehending interfacial loss and developing approaches to ameliorate interfacial features is essential. Nonradiative recombination at the SnO2-perovskite interface in SnO2-based perovskite solar cells (PSCs) leads to significant potential loss and variability in device performance. To improve the quality of the SnO2 electron transport layer, a novel polymer-doped SnO2 matrix, specifically using polyacrylic acid, was developed. This matrix is formed by spin-coating a SnO2 colloidal solution that includes polymers. The polymer aids in dispersing nanoparticles within the substrate and is evenly distributed in the SnO2 solution. As a result of the polymer addition, the density and wetting properties of the SnO2 layer substantially improved. Subsequently, perovskite-based photovoltaic devices comprising SnO2 and Spiro-OMeTAD layers and using (FAPbI3)0.97(MAPbBr3)0.03 perovskite are constructed. These optimized devices exhibited an increased efficiency of 17.2% when compared to the 15.7% power conversion efficiency of the control device. The incorporation of polymers in the electron transport layer potentially enables even better performance in planar perovskite solar cells.

High Open‐Circuit Voltage (1.197 V) in Large‐Area (1 cm2) Inverted Perovskite Solar Cell via Interface Planarization and Highly Polar Self‐Assembled Monolayer

AbstractThe efficiency loss caused by area scaling is one of the key factors hindering the industrial development of perovskite solar cells. The energy loss and contact issues in the buried interface are the main reasons. Here, a new self‐assembled monolayer (SAM), Ph‐4PACz, with a large dipole moment (2.32 D) is obtained . It is found that Ph‐4PACz with high polarity can improve the band alignment and minimize the energy loss , resulting in an open‐circuit voltage (Voc) as high as 1.2 V for 1.55 eV perovskite. However, when applied to large‐area devices, the fill factor (FF) still suffered from significant attenuation. Therefore, alumina nanoparticles (Al2O3‐NPs) are introduced to the interface between Ph‐4PACz and rough FTO substrate to further improve the flatness , resulting in a conformal perovskite film with almost no voids in the buried interface, thus promoting low exciton binding energy, fast hot‐carrier extraction and low non‐radiative recombination. The final devices achieved a small‐area power conversion efficiency (PCE) of 25.60% and a large‐area (1 cm2) PCE of 24.61% (certified at 24.48%), which represents one of the highest PCE for single device ≥ 1 cm2 area. Additionally, mini‐modules and stability testing are also carried out to demonstrate the feasibility of commercialization.

ZnO/SnO2 bilayer electron transport layer strategy to improve the performance of FAPbI3 solar cell

In recent years, organic–inorganic hybrid perovskite (PVK) devices have attracted widespread attention with their high absorption coefficient and low-cost fabrication process. Formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs) have been reported to obtain high power conversion efficiencies (PCEs) due to the narrow bandgap. Zinc oxide (ZnO) has better electrical conductivity and high transmittance than tin (IV) dioxide (SnO2). However, the deprotonation behavior of ZnO limits its use in formamidinium (FA) or methylammonium (MA) devices, so it is mostly used in all-inorganic PSCs. In this work, to avoid the deprotonation behavior of ZnO, we prepared FAPbI3 PSCs using ZnO/SnO2 as bilayer electron transporting layers (ETLs), which improved the conductivity of the ETLs and promoted electron extraction and transfer. In addition, the decrease in the oxygen vacancy (Ov) on the bilayer ETLs contributed to the suppression of the non-radiative recombination of the device, thus enabling the achievement of a higher fill factor. As a result, the modified ETLs increased the PCE of FAPbI3 PSCs from 20.24% to 21.42% and improved the stability of the devices. The PCE of unpackaged devices increased steadily to 21.91% when stored in an N2 atmosphere for 183 days.

Design of Star‐Shaped Trimer Acceptors for High‐Performance (Efficiency > 19%), Photostable, and Mechanically Robust Organic Solar Cells

AbstractHigh power conversion efficiency (PCE), long‐term stability, and mechanical robustness are prerequisites for the commercial applications of organic solar cells (OSCs). In this study, a new star‐shaped trimer acceptor (TYT‐S) is developed and high‐performance OSCs with a PCE of 19.0%, high photo‐stability (t80% lifetime = 2600 h under 1‐sun illumination), and mechanical robustness with a crack‐onset strain (COS) of 21.6% are achieved. The isotropic molecular structure of TYT‐S affords efficient multi‐directional charge transport and high electron mobility. Furthermore, its amorphous structure prevents the formation of brittle crystal‐to‐crystal interfaces, significantly enhancing the mechanical properties of the OSC. As a result, the TYT‐S‐based OSCs demonstrate a significantly higher PCE (19.0%) and stretchability (COS = 21.6%) than the linear‐shaped trimer acceptor (TYT‐L)‐based OSCs (PCE = 17.5% and COS = 6.4%) and the small‐molecule acceptor (MYT)‐based OSCs (PCE = 16.5% and COS = 1.3%). In addition, the increased molecular size of TYT‐S, relative to that of MYT and dimer (DYT), suppresses the diffusion kinetics of the acceptor molecules, substantially improving the photostability of the OSCs. Finally, to effectively demonstrate the potential of TYT‐S, intrinsically stretchable (IS)‐OSCs are constructed. The TYT‐S‐based IS‐OSCs exhibit high device stretchability (strain at PCE80% = 31%) and PCE of 14.4%.

Effect of fluorine on the photovoltaic properties of 2,1,3-benzothiadiazole-based alternating conjugated polymers by changing the position and number of fluorine atoms.

Fluorination is one of the most effective ways to manipulate molecular packing, optical bandgap and molecular energy levels in organic semiconductor materials. In this work, different number of fluorine atoms was introduced into the acceptor moiety 2,2'-dithiophene linked 2,1,3-benzothiadiazole, utilizing the alkylthiophene modified dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b] (DTBDT) as the donor unit, three polymers: PDTBDT-0F-BTs, PDTBDT-2F-BTs and PDTBDT-6F-FBTs were synthesized. With the number of fluorine atoms in each repeat unit of polymers varying from 0 to 2 and then up to 6, PDTBDT-0F-BTs, PDTBDT-2F-BTs and PDTBDT-6F-FBTs exhibited gradually downshifted energy levels and improved dielectric constants (εr) from 3.4 to 4.3 to 5.8, further successively increased charge transport mobilities. As a result, the power conversion efficiency (PCE) of the bulk heterojunction organic photovoltaic devices (BHJ-OPV) from the blend films of aforementioned polymers paired with PC71BM were gradually increased from 1.69 for PDTBDT-0F-BTs to 1.89 for PDTBDT-2F-BTs and then to 5.28 for PDTBDT-6F-FBTs. The results show that the continuous insertion of fluorine atoms into the repeating units of the benzothiadiazole conjugated polymer leads to the deepening of HOMO energy level, the increase of εr and the increase of charge mobility, which improve the efficiency of charge transfer and electron collection, thus improving the photovoltaic performance of BHJ-OPV.

Benzoic acid inhibits intrinsic ion migration for efficient and stable perovskite solar cells.

An efficient perovskite solar cell (PSC) has the following characteristics: (1) large perovskite grain size; (2) small ion migration; (3) low defect density states. Here, benzoic acid was employed as an additive to a perovskite solution to improve the thin film quality. Surprisingly, 1.0%-BA can implement all of these features. Therefore, the power conversion efficiency (PCE) of the champion PSC is 18.05%, which is superior to that of the control device (15.42%). In addition, BA-doped PSC kept 86% of its primary PCE after 30 days (RH: 35%), but the control device only retained 75% under the same conditions. The improvement of its stability is because of the inhibition of the cation migration of perovskite by the addition of BA and the passivation of perovskite defects. The results can acquire a better understanding of the potential applications of small organic molecules in improving the PCE and stability of PSC devices.

Mimicking Natural Antioxidant Systems for Improved Photostability in Wide-Band-Gap Perovskite Solar Cells.

Fostered by the top power conversion efficiencies (PCEs) of lab-scale devices, industrialization of perovskite solar cells is underway. Nevertheless, the intrinsically poor stability of these materials still represents a major concern. Herein, inspired by Nature, the use of β-carotene in perovskite solar cells is proposed to mimic its role as a protective pigment, as occurs in natural photosynthesis. Laser-mediated photostability (LMPS) assessment, Fourier-transform infrared spectra analysis acquired in attenuate total reflectance (ATR-FTIR), spectroscopy ellipsometry (SE), and time-resolved photoluminescence (TRPL) measurements under stress conditions prove that the inclusion of a thin β-carotene interlayer promotes a high improvement in the photostability of the perovskite films against photooxidation. Importantly, this is accompanied by an improvement of the solar cell PCE that approaches 20% efficiency with no hysteresis, which is among the highest values reported for a mixed halide (I-Br) perovskite with a band gap of 1.74 eV, relevant for coupling with silicon in tandem cells.

Facile Posttreatment of Self‐Assembled Monolayers for Efficient Inverted Perovskite Solar Cells

The application of self‐assembled molecules (SAM) allows inverted‐structural perovskite solar cells to accomplish high efficiencies, by virtue of their high hole conductivity and negligible parasitic absorption. However, amphiphilic SAM tend to form spherical micelles in commonly used alcoholic solvents, leading to aggregation in the resulting film. In addition, hydrophobic groups of SAM are exposed to the surroundings after being deposited on transparent substrates, responsible for the poor crystallinity of perovskite and interface quality. Therefore, it is important to study the treatment of SAM layers or SAM/perovskite interfaces for better device performance. Herein, dual regulation of SAM and perovskite is achieved via a facile posttreatment by formamidinium chloride (FACl) solution in N,N‐Dimethylformamide. First, by taking advantage of solvent rinsing, aggregations at the surface of SAM layer are alleviated. Second, FACl on the top of the SAM layer assists the crystallization of perovskite through interaction with PbI2 and reduces the defect concentration via passivating the halide vacancies at the buried interface of the device. With a more uniform SAM layer, better‐crystallized perovskite, and suppressed nonradiative recombination between them, the power conversion efficiency of the target device is improved by 20%.

Rotaxane-Functionalized Dyes for Charge-Rectification in p-Type Photoelectrochemical Devices.

A supramolecular photovoltaic strategy is applied to enhance power conversion efficiencies (PCE) of photoelectrochemical devices by suppressing electron-hole recombination after photoinduced electron transfer (PET). Here, the author exploit supramolecular localization of the redox mediator-in close proximity to the dye-through a rotaxane topology, reducing electron-hole recombination in p-type dye-sensitized solar cells (p-DSSCs). Dye PRotaxane features 1,5-dioxynaphthalene recognition sites (DNP-arms) with a mechanically-interlocked macrocyclic redox mediator naphthalene diimide macrocycle (3-NDI-ring), stoppering synthetically via click chemistry. The control molecule PStopper has stoppered DNP-arms, preventing rotaxane formation with the 3-NDI-ring. Transient absorption and time-resolved fluorescence spectroscopy studies show ultrafast (211 ± 7 fs and 2.92 ± 0.05ps) PET from the dye-moiety of PRotaxane to its mechanically interlocked 3-NDI-ring-acceptor, slowing down the electron-hole recombination on NiO surfaces compared to the analogue . p-DSSCs employing PRotaxane (PCE = 0.07%) demonstrate a 30% PCE increase compared to PStopper (PCE = 0.05%) devices, combining enhancements in both open-circuit voltages (VOC = 0.43 vs 0.36V) and short-circuit photocurrent density (JSC = -0.39vs -0.34mA cm-2 ). Electrochemical impedance spectroscopy shows that PRotaxane devices exhibit hole lifetimes (τh ) approaching 1 s, a 16-fold improvement compared to traditional I- /I3 - -based systems (τh = 50ms), demonstrating the benefits obtained upon nanoengineering of interfacial dye-regeneration at the photocathode.

Recent Developments in Atomic Layer Deposition of Functional Overlayers in Perovskite Solar Cells.

Over the last decade, research in organic-inorganic lead halide perovskite solar cells (PSCs) has gathered unprecedented momentum, putting the technology on the brink of full-scale commercialization. A wide range of strategies have been implemented for enhancing the power conversion efficiency of devices and modules, as well as improving stability toward high levels of irradiation, temperature, and humidity. Another key element in the path to commercialization is the scalability of device manufacturing, which requires large-scale deposition of conformal layers without compromising the delicate structure of the perovskite film. In this context, atomic layer deposition (ALD) tools excel in depositing high-quality conformal films with precise control of film composition and thickness over large areas at relatively low processing temperatures. In this commentary, we will briefly outline recent progress in PSC technology enabled by ALD tools, focusing on layers deposited above the absorber layer. These interlayers include charge transport layers, passivation layers, buffer layers, and encapsulation techniques. Additionally, we will discuss some of the challenges and potential avenues for research in PSC technology underpinned by ALD tools.

Efficiency of Emerging Photovoltaic Devices under Indoor Conditions

Emerging photovoltaic (PV) technologies are considered to be excellent candidates to be used as power sources for indoor and low‐light applications. The already demonstrated high power conversion efficiencies (PCEs) and the potential to manufacture perovskite, organic, or dye‐sensitized solar cells at low cost make them particularly interesting. In this work, the maximum PCE of PV devices under low‐light conditions is explored. The role of spectral mismatch, non‐radiative recombination, and parasitic Ohmic losses is investigated. The performed calculation provides guidelines to improve the low‐light performance of PV devices for ambient light. In addition, a simple measurement procedure for the indoor PCE is discussed.

Understanding the Dominant Physics Mechanisms on the p‐i‐n Perovskite Solar Cells Fabricated by Scalable Slot‐Die Coating Process in Ambient Air

Perovskite solar cells (PSC) are emerging technologies that have shown continuous improvement in power conversion efficiency (PCE) and stability. However, a very important aspect that has been seldom considered is the reproducibility of PCE of PSC devices. It is possible to achieve PCE from 10.21% to 17.05% using scalable slot‐die‐coating technique. However, a spatial distribution of performance is clearly observed for device samples on a 4 × 4 cm substrate. The relatively low PCE is mainly coming from the losses of electrical mechanism. To have in‐depth understanding of the losses, the dominant loss analysis techniques including numerical simulations are used to explore the mechanism. In the results, it is indicated that a part of efficiency decrease is due to the increase of bulk defect density which linearly changes with the quality of the perovskite layer and related to recombination process. However, extremely high‐charge‐carrier transportation losses are found at the HTL/perovskite interface that are related to the Fermi‐level pinning mechanism for low‐efficiency device. The result of physics insight of perovskite solar cells leads to a strategy, where chemical passivation technique is used to achieve the PCE from 13.81% to 18.07% for the batch of devices with good reproducibility.

Data-driven design for enhanced efficiency of Sn-based perovskite solar cells using machine learning

In this study, a novel three-step learning-based machine learning (ML) methodology is developed utilizing 26 000 experimental records from The Perovskite Database Project. A comprehensive set of 29 features encompassing both categorical and numerical data was utilized to train various ML models for various solar cell performance metrics, including open-circuit voltage (VOC), short-circuit current (JSC), fill factor (FF), and power conversion efficiency (PCE). The model accuracy was assessed using four key metrics: mean absolute error, mean square error, root mean square error, and R2 score. Among the constructed models, random forest (RF) emerged as the standout performer, boasting an R2 score of 0.70 for PCE. This RF model was then used for prediction on the large, optimized design pool of Sn-based perovskite data with intent to probe a viable non-toxic substitute to the standard Pb-based absorber. A three-step algorithm was tailored, which led to the discovery of a new set of feature combinations, showcasing a PCE improvement over the existing peak performance of Sn-based devices. The key aspects identified were device architecture, dimensionality, and deposition procedures for essential layers, including the electron transport layer, the hole transport layer, the perovskite absorber layer, and the back-contact. Through consideration of these features, an impressive increase in PCE was achieved. There was a 28.35% increase in PCE from 12.24% to 15.71% for architecture optimization and a 24.6% increase in PCE from 12.24% to 15.25% for deposition method optimization. This study additionally addresses the effective implementation of target encoding applied to a diverse set of categorical feature labels. The data-driven methodology proposed in this study allows scientists to efficiently identify an optimal architecture and deposition parameters for non-toxic Sn-based perovskite materials with a much higher anticipated device PCE compared to traditional trial-and-error analyses. Further exploration and exploitation of the current investigation is expected to lead to successful and sustainable development of highly efficient Sn-based perovskite solar cells.

Ultrasonic Spray Deposition of a Passivating Agent for Spray‐Coated, Methylammonium‐Free Perovskite Solar Cells

Defect management in perovskite solar cells (PSCs) via surface passivation has become a cornerstone in maximizing both stability and solar‐to‐electrical power conversion efficiency (PCE) of devices by reducing defect densities and/or improving energetic alignment between the perovskite and charge‐transporting layers. Despite this, few reports explore the use of roll‐to‐roll compatible technologies to deposit such interfacial treatments, limiting the applicability of passivation in real‐world contexts. In this work, iso‐butylammonium bromide (i‐BABr) is spray‐coated onto a Cs0.15FA0.85PbI2.85Cl0.15 perovskite surface which is deposited using gas‐assisted ultrasonic spray coating. It is found that i‐BABr treatments result in the formation of a quasi‐2D perovskite layer. The spray‐coated surface treatment results in an impressive 80 mV improvement in the median open‐circuit voltage with respect to untreated devices. Importantly, the spray‐coated passivation results in very similar positive benefits to the application of spin‐coated treatments demonstrating the promise of the spray‐passivation methodology. It is shown that devices created in this manner demonstrate PCEs of up to 21.0% (19.4% stabilized), representing the highest reported efficiency for one‐step, spray‐coated methylammonium‐free PSCs. This work represents the first demonstration of a spray‐coated surface passivation treatment that is compatible with high‐throughput, roll‐to‐roll processing.

Role of interface engineering in amorphous InGaZnO ETL for non-fullerene organic solar cells

Amorphous metal-oxide semiconductors have been developed as prospective substitutes for organic and silicon compounds, and their applications have been expanded due to their superior mobility in amorphous phase. As a result, this study demonstrated a facile approach to amend the interface quality by oxygen vacancy engineering. Here, we compared the performance of optimized oxygen-deficient (Od) and oxygen-rich (Or) amorphous indium–gallium–zinc oxide (a-IGZO) electron transport layers (ETL) for non-fullerene organic solar cells (OSCs). The ETL was fabricated using rf magnetron sputtering by changing oxygen contents. The power conversion efficiency (PCE) of Or device is 5.1 %, which was boosted to 6.6 % for Od device. The device with Od a-IGZO ETL outperforms the Or device, as the oxygen vacancies in Od device aid as electron donors, which deliver free electron carriers to IGZO film. These free electron carriers promote electron concentration, device mobility and deteriorate the resistivity, which facilitate charge transport and collection towards the electrode. Furthermore, devices improved their stability, as device with Od a-IGZO ETL retained almost 80 % of its initial PCE in ambient conditions. Consequently, interfacial engineering has played a crucial role in bringing OSC towards commercialization as it has substantial influence on charge collection and transport properties in devices.

Interface optimization and defects suppression via NaF introduction enable efficient flexible Sb2Se3 thin-film solar cells

Sb2Se3 with unique one-dimensional (1D) crystal structure exhibits exceptional deformation tolerance, demonstrating great application potential in flexible devices. However, the power conversion efficiency (PCE) of flexible Sb2Se3 photovoltaic devices is temporarily limited by the complicated intrinsic defects and the undesirable contact interfaces. Herein, a high-quality Sb2Se3 absorber layer with large crystal grains and benign [hk1] growth orientation can be first prepared on a Mo foil substrate. Then NaF intermediate layer is introduced between Mo and Sb2Se3, which can further optimize the growth of Sb2Se3 thin film. Moreover, positive Na ion diffusion enables it to dramatically lower barrier height at the back contact interface and passivate harmful defects at both bulk and heterojunction. As a result, the champion substrate structured Mo-foil/Mo/NaF/Sb2Se3/CdS/ITO/Ag flexible thin-film solar cell delivers an obviously higher efficiency of 8.03% and a record open-circuit voltage (VOC) of 0.492 V. This flexible Sb2Se3 device also exhibits excellent stability and flexibility to stand large bending radius and multiple bending times, as well as superior weak light photo-response with derived efficiency of 12.60%. This work presents an effective strategy to enhance the flexible Sb2Se3 device performance and expand its potential photovoltaic applications.

Observation on structural and optical features of new nanostructured lead-free methylammonium zinc or cobalt iodide perovskites for solar cells applications

The toxicity of lead-based halide perovskites has become a significant drawback to be employed in optoelectronic devices. Therefore, developing other environmentally friendly candidates with tunable optoelectronic properties for highly efficient solar cells is indispensable. Lead-free perovskite solar cells (PSCs) are promising to have a crucial role in large-scale commercial non-toxic photovoltaic devices. Here, the microstructure and optoelectronic properties of 2D halide perovskites without pb (CH3NH3)2BI4 (where B = Zn or Co) have been investigated for use in solar cells. The synthesized samples are characterized by X-ray diffraction (XRD), Raman spectroscopy, FT-IR, FESEM, and TEM. The variation in the optical and photoluminescence (PL) is recognized. The results indicate that (CH3NH3)2ZnI4 and (CH3NH3)2CoI4 crystals demonstrate a wide band gap of about 2.42 and 1.87 eV, respectively. A comparative study is presented for the optical properties of Zn- versus Co-based perovskites. It is noticed that Co is a better candidate than Zn to be a good replacement choice for Pb as Co-containing compounds have lower optical bandgap than Zn-containing compounds. PCBM is employed as a hole transport material, and PEDOT:PSS as an electron transport layer. The p-i-n PSCs are fabricated, and the electrical parameters are measured, obtaining power conversion efficiencies (PCE) of 0.73 and 2.45% for (CH3NH3)2ZnI4 and (CH3NH3)2CoI4, respectively. This work opens the door for further investigations to increase the PCE of both devices.

Morphological investigation and 3D simulation of plasmonic nanostructures to improve the efficiency of perovskite solar cells

The light absorption process is a key factor in improving the performance of perovskite solar cells (PSCs). Using arrays of metal nanostructures on semiconductors such as perovskite (CH3NH3PbI3), the amount of light absorption in these layers is significantly increased. Metal nanostructures have been considered for their ability to excite plasmons (collective oscillations of free electrons). Noble metal nanoparticles placed inside solar cells, by increasing the scattering of the incident light, effectively increase the optical absorption inside PSCs; this in turn increases the electric current generated in the photovoltaic device. In this work, by calculating the cross-sectional area of dispersion and absorption on gold (Au) nanoparticles, the effects of the position of nanoparticles in the active layer (AL) and their morphology on the increase of absorption within the PSC are investigated. The optimal position of the plasmonic nanoparticle was obtained in the middle of the AL using a three-dimensional simulation method. Then, three different morphologies of nano-sphere, nano-star and nano-cubes were investigated, where the short-circuit currents (Jsc) for these three nanostructures were obtained equal to 19.01, 18.66 and 20.03 mA/cm2, respectively. In our study, the best morphology of the nanostructure according to the Jsc value was related to the nano-cube, in which the device power conversion efficiency was equal to 16.20%, which is about 15% better than the PSC with the planar architecture.