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In this work, a comparative analysis was carried out by using titanium dioxide (TiO2) and tungsten disulfide (WS2) as an electron transport layer (ETL). This numerical analysis was conducted using SCAPS-1D software, which stands for solar cell capacitance simulator-1 Dimensional. The two device structures were: FTO/TiO2/N719/ MoO3 and FTO/WS2/N719/MoO3. For TiO2 ETL-based devices, the PCE was 11.42%, with J sc, V oc, and FF values of 18.50 mA cm−2, 0.872 V, and 70.75%, respectively. By contrast, WS2-based devices achieved a PCE of 14.23% with J sc, V oc, and FF values of 20.86 mA cm−2, 0.880 V, and 77.43%, respectively. Based on the above-mentioned data, WS2 has better PV performance of the solar cell. WS2 exhibits high electron mobility, chemically stable, tunable bandgap, therefore a promising candidate to replace TiO2 as an ETL in future designs. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO2) with high conductivity and excellent photostability has been considered as one of the most promising materials for efficient electron transport layer (ETL) in perovskite solar cells (PSCs). Among them, SnO2 nanoparticles (NPs) dispersions have been extensively utilized due to their facile film formation. However, the inherent defects and agglomeration issues of SnO2 NPs, as well as the limited tunability and instability of the post‐treatment process for surface/interface engineering strategy, still hinder its further applications. Herein, a ligand‐management strategy implemented during the in situ synthesis of NPs that can effectively achieve uniform modification of NPs is proposed. During the synthesis of SnO2 NPs, the grafting reaction between diethyl 2‐chloromalonate (DCMA) and the surface of SnO2 NPs is completed. Compared with the post‐treatment process, this intrinsic DCMA‐passivated SnO2 (DCMA‐SnO2) effectively reduces the trap state density at the interface between perovskite and ETL while enhancing surface chemical stability. Consequently, PSCs based on DCMA‐SnO2 achieve a champion PCE of 25.39% for small cells (active area of 0.0655 cm2) and 20.61% for solar modules (active area of 23.25 cm2), demonstrating excellent shelf‐life/light soaking stability (advanced level of ISOS stability protocols). This ligand‐management strategy exhibits significant application potential in preparing high‐efficiency large‐area PSCs. [ABSTRACT FROM AUTHOR]

This article reviews the latest advancements in perovskite solar cell (PSC) components for innovative photovoltaic applications. Perovskite materials have emerged as promising candidates for next-generation solar cells due to their exceptional light-absorbing capabilities and facile fabrication processes. However, limitations in their stability, scalability, and efficiency have hindered their widespread adoption. This review systematically explores recent breakthroughs in PSC components, focusing on absorbed layer engineering, electron and hole transport layers, and interface materials. In particular, it discusses novel perovskite compositions, crystal structures, and manufacturing techniques that enhance stability and scalability. Additionally, the review evaluates strategies to improve charge carrier mobility, reduce recombination, and address environmental considerations. Emphasis is placed on scalable manufacturing methods suitable for large-scale integration into existing infrastructure. This comprehensive review thus provides researchers, engineers, and policymakers with the key information needed to motivate the further advancements required for the transformative integration of PSCs into global energy production. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have acquired popularity owing to their high efficiency, ease of fabrication, and affordability. In this context, the development of electron transport layers (ETLs) for highly efficient planar photovoltaic devices has received considerable attention. This study investigates the potential of zinc‐tin‐based ternary metal oxide ETLs for application in planar PSCs. Solution‐processed methods are used to fabricate crystalline zinc stannate (Zn2SnO4), amorphous zinc‐tin oxide (ZTO), and Zn2SnO4/ZTO‐based bilayer films, and their structural, morphological, and optoelectronic properties are thoroughly studied. X‐ray diffraction (XRD) analysis and scanning electron microscopy (SEM) images show enhanced crystallite size and better surface morphology of perovskite films deposited on bilayer ETL. Photoluminescence (PL) studies and Hall effect measurements reveal superior charge extraction, improved charge carrier mobility (21.84 cm2 V−1 s−1) and enhanced n‐type conductivity in the bilayer ETL. Moreover, contact angle analysis of perovskite layer deposited on bilayer ETL shows increased resistance to moisture erosion (52.20°), which is particularly significant given the detrimental effects moisture can have on the performance of PSCs. [ABSTRACT FROM AUTHOR]

Indoor organic photovoltaic (OPV) cells offer a compelling solution for powering diverse electronic devices integrated into the Internet of Things (IoT) network. They are prized for their robust power conversion efficiency (PCE), mechanical resilience, and ultra‐thin nature. The recent surge in inverted‐structure OPVs reflects their enhanced stability over conventional designs. Despite the advantage, their adaptation for indoor light utilization remains underexplored. Optimal selection of an electron transport layer (ETL) with precise energy band alignment is critical in this system. Herein, an inverted‐structured OPV is fabricated utilizing PBDB‐T as the wide bandgap donor, with a focus on enhancing its PCE under 1000 lx LED illumination through the doping of the zinc oxide‐ (ZnO‐) based ETL with indium (In). The results indicate that the device utilizing undoped ZnO as the ETL achieves a peak PCE of 9.42% under these specified conditions. Conversely, the OPV utilizing In‐doped ZnO as the ETL achieves a significantly higher PCE of 29.78% with 5 at% In, indicates the usefulness of ETL doping by In. This may be caused by the tuning of energy band alignment, improvement in electron mobility, and reduction in surface roughness of ZnO by In doping. [ABSTRACT FROM AUTHOR]

The interface modification between perovskite and electron transport layer (ETL) plays a crucial role in achieving high performance inverted perovskite photovoltaics (i‐PPVs). Herein, non‐fullerene acceptors (NFAs), known as Y6‐BO and Y7‐BO, were utilized to modify the perovskite/ETL interface in i‐PPVs. Non‐polar solvent‐soluble NFAs can effectively passivate surface defects without structural damage of the underlying perovskite films. Additionally, the improved phenyl‐C61‐butyric acid methyl ester (PCBM) ETL induced by NFAs modification significantly accelerates the electrons extraction. As a result, both Y6‐BO and Y7‐BO exhibit more effective interface modification effects compared to traditional PI molecules. The power conversion efficiency (PCE) of the inverted perovskite solar cell (i‐PSC) modified with Y7‐BO reaches 25.82 %. Moreover, the adoption of non‐polar solvents and the superior semiconductor properties of Y7‐BO molecules also enable perovskite solar modules (i‐PSM) with effective areas of 50 cm2, 400 cm2, and 1160 cm2 to achieve record efficiencies of 23.05 %, 22.32 %, and 21.1 % (certified PCE), respectively, making them the best PCE reported in the literature. Importantly, enhanced interface mechanical strength between the perovskite and PCBM layer results in significantly improved environmental and operational stability of the cells. The cells modified with Y7‐BO maintained 94.4 % of the initial efficiency after 1522 hours of maximum power point aging. [ABSTRACT FROM AUTHOR]

In this paper, we study the effects of Cu, Ni, and Zn doping in TiO2 layers on the performance of MAPbI3-based perovskite solar cells (PSCs) fabricated under ambient air with relative humidity between 60% and 70%. One of the factors limiting the efficiency of MAPbI3-based PSCs is the TiO2 electron transport layer properties. The efficiency of PSCs is the maximum power that can be produced by a PSC when illuminated by light with a specific energy. This study aims to enhance MAPbI3-based PSC efficiency by doping TiO2 with 2 mol.% Cu, Ni, and Zn. MAPbI3-based PSCs were then fabricated using spin coating with the structure ITO/TiO2/MAPbI3/graphite/ITO. X-ray diffraction and scanning electron microscopy (SEM) analyses revealed that doping reduced TiO2 crystal sizes from 19.34 nm (pure) to 18.96 nm (Cu-doped), 18.04 nm (Ni-doped), and 17.6 nm (Zn-doped), with corresponding average particle sizes of 225 nm, 107 nm, 79 nm, and 50.4 nm. Ultraviolet–visible (UV–Vis) spectroscopy indicated an increase in the bandgap from 3.0 eV (pure) to 3.1 eV (Cu-doped), 3.2 eV (Ni-doped), and 3.25 eV (Zn-doped). Current–voltage (I–V) electrical testing revealed improvement in efficiency from 5.7% (undoped) to 7.6% (Cu-doped), 6.9% (Ni-doped), and 8.01% (Zn-doped). These findings demonstrate that metal-doped TiO2 significantly enhances the efficiency of MAPbI3-based PSCs fabricated in open-air environments without the need for a glove box. [ABSTRACT FROM AUTHOR]

We developed inverted red quantum dot light-emitting diodes (QLEDs) with ZnO nanoparticles synthesized in open and closed systems. Wurtzite-structured ZnO nanoparticles were synthesized using potassium hydroxide and zinc acetate dihydrate at various temperatures in the open and closed systems. The particle size increases with increasing synthesis temperature. The ZnO nanoparticles synthesized at 50, 60, and 70 °C in the closed system have an average particle size of 3.2, 4.0, and 5.4 nm, respectively. The particle size is larger in the open system compared to the closed system as the methanol solvent evaporates during the synthesis process. The surface defect-induced emission in ZnO nanoparticles shifts to a longer wavelength and the emission intensity decreases as the synthesis temperature increases. The inverted red QLEDs were fabricated with a synthesized ZnO nanoparticle electron transport layer. The driving voltage of the inverted QLEDs decreases as the synthesis temperature increases. The current efficiency is higher in the inverted red QLEDs with the ZnO nanoparticles synthesized in the closed system compared to the devices with the nanoparticles synthesized in the open system. The device with the ZnO nanoparticles synthesized at 60 °C in the closed system exhibits the maximum current efficiency of 5.8 cd/A. [ABSTRACT FROM AUTHOR]

Sol–gel processed zinc oxide (ZnO) is one of the most widely used electron transport layers (ETLs) in inverted organic solar cells (OSCs). The high annealing temperature (≈200 °C) required for sintering to ensure a high electron mobility however results in severe damage to flexible substrates. Thus, flexible organic solar cells based on sol–gel processed ZnO exhibit significantly lower efficiency than rigid devices. In this paper, an indium‐doping approach is developed to improve the optoelectronic properties of ZnO layers and reduce the required annealing temperature. Inverted OSCs based on In‐doped ZnO (IZO) exhibit a higher efficiency than those based on ZnO for a range of different active layer systems. For the PM6:L8‐BO system, the efficiency increases from 17.0% for the pristine ZnO‐based device to 17.8% for the IZO‐based device. The IZO‐based device with an active layer of PM6:L8‐BO:BTP‐eC9 exhibits an even higher efficiency of up to 18.1%. In addition, a 1.2‐micrometer‐thick inverted ultrathin flexible organic solar cell is fabricated based on the IZO ETL that achieves an efficiency of 17.0% with a power‐per‐weight ratio of 40.4 W g−1, which is one of the highest efficiency for ultrathin (less than 10 micrometers) flexible organic solar cells. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) material plays a crucial role in determining the device efficiency and stability of organic solar cells (OSCs). Tin oxide (SnO2) semiconductor is commonly used as ETL in organic solar cells and recently has attracted significant attention. In this paper SnO2 particles deposited by pulsed laser deposition (PLD) are used as ETL layer in inverted organic solar cells with structure (FTO/SnO2/PTB7-Th:O-IDTBR/ MoO3/Ag). The characterizations of cell using the Ossila Solar Cell I-V Test System have been investigated as well as the structural properties of SnO2 thin film using a Field emission scanning electron microscope (FESEM), The atomic force microscopy (AFM) and X-ray spectrum have been also investigated. It has been found that the Power conversion efficiency (PCE) of solar cell is 15.08 %. The stability was measured for 30 min with continuous illumination under the ambient air conditions, it was decreasing gradually over the illumination period to about half initial value of efficiency. The FESEM images and XRD spectrum show that the films were crystalline. The XRD spectrum shows the presence of several peaks belonging to SnO2 nanoparticles. The optical properties of SnO2 film indicate the increase in the transmittance and refractive index spectrum, while the absorbance spectrum decreases, the maximum absorbance was observed at 320 nm wavelength and the optical energy gap record about 3.1 eV and the grain size for SnO2 reported around 20–60 nm. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb2Se3) has developed as an eco‐friendly photovoltaic candidate owing to its non‐toxic composition and exceptional optoelectronic properties. However, the toxic and parasitic light‐absorbing CdS are widely used as electron transport layer (ETL) in Sb2Se3 solar cells, which severely limits its development. Herein, an alternative, zinc tin oxide (ZTO) ETL with varying composition‐dependent energy structure is deposited by atomic layer deposition (ALD) technique and used for constructing Cd‐free Sb2Se3 solar cells. It has been found that the ZTO ETL possessing an appropriate Zn/Sn ratio can alter the Sb2Se3/ZTO heterojunction band alignment to an ideal "spike‐like" arrangement. It not only suppresses the accumulation and recombination of charge carriers at the interface, but also effectively enhances carrier transport. In addition, thanks to the formation of passivated Sb2O3 ultra‐thin layer upon ALD process, the non‐radiative recombination within bulk Sb2Se3 can be effectively suppressed, and therefore enhancing carrier lifetime, extraction efficiency, and collection efficiency. Consequently, the as‐fabricated Mo/Sb2Se3/ZTO/ITO/Ag thin‐film solar cell demonstrates an impressive efficiency of 8.63%. This accomplishment establishes it as the most efficient Cd‐free Sb2Se3 solar cell to date, underscoring the significant advantages of incorporating ZTO ETL in the development of Sb2Se3 photovoltaic scenarios. [ABSTRACT FROM AUTHOR]

When implementing optoelectronic devices through the stacking of heterogeneous materials, considering the bandgap offset is crucial for achieving efficient carrier dynamics. In this study, the bandgap offset characteristics are investigated when n‐type gallium nitride nanowires (n‐GaN NWs) are used as electron transport layers in methylammonium lead iodide (MAPbI3)‐based optoelectronic devices. n‐GaN NWs are grown on indium‐tin‐oxide (ITO)‐coated glass via the plasma‐assisted molecular beam epitaxy (PA‐MBE) process to form the "GaN NWs‐on‐glass" platform. A MAPbI3 thin film is then spin‐coated on the GaN NWs‐on‐glass. X‐ray photoelectron spectroscopy (XPS) shows that the valence and conduction band offsets in the MAPbI3/n‐GaN heterostructure are 2.19 and 0.40 eV, respectively, indicating a type‐II band alignment ideal for optoelectronic applications. Prototype photovoltaic devices stacking perovskite on GaN NWs‐on‐glass show excellent interfacial charge‐transfer ability, photon recycling, and carrier extraction efficiency. As a pioneering step in exploiting the diverse potential of the GaN‐on‐glass, it is demonstrated that the junction characteristics of MAPbI3/n‐GaN NW heterostructures can lead to a variety of optoelectronic device applications. [ABSTRACT FROM AUTHOR]

As an electron transport layer (ETL) widely used in organic solar cells (OSCs), ZnO has problems with energy level mismatch with the active layer and excessive defects on the ZnO surface, which can reduce the efficiency of OSCs. Here, ZnO/ZrSe2 composite is fabricated by modifying ZnO with 2D ZrSe2. The XPS and first‐principles calculation (FPC) show that ZnO obtains electrons from ZrSe2 and forms interfacial dipoles toward the active layer, which decreases the work function of ZnO, thus reducing the interface barrier and favoring the collection of electrons in OSCs. At the same time, after ZrSe2 modification, the oxygen vacancy density on the ZnO surface decreases, thus improving the conductivity of ZnO. More importantly, the femtosecond transient absorption (Fs‐TA) shows that ZrSe2 selectively traps holes from the active layer, which prevents the holes from entering the ZnO, thereby reducing the probability of electron recombination. Finally, ZnO/ZrSe2 composite is used as a novel ETL in OSCs with PBDB‐T: ITIC, PM6:Y6 and PM6: L8‐BO as active layers, and obtaining 12.09%, 16.34%, and 18.24% efficiency, respectively. This study provides a method for the interface modification of ZnO, and further investigates the role of 2D nanosheets in the interface modification. [ABSTRACT FROM AUTHOR]

The buried interface between the electron transport layer (ETL) and the perovskite layer plays a crucial role in enhancing the power conversion efficiency (PCE) and stability of n–i–p type perovskite solar cells (PSCs). In this study, the interface between the chemical bath deposited (CBD) titanium oxide (TiO2) ETL and the perovskite layer using multi‐functional potassium trifluoromethyl sulfonate (SK) is modified. Structural and elemental analyses reveal that the trifluoromethyl sulfonate serves as a crosslinker between the TiO2 and the perovskite layer, thus improving the adhesion of the perovskite to the TiO2 ETL through strong bonding of the ─CF3 and ─SO3− terminal groups. Furthermore, the multi‐functional modifiers reduced interface defects and suppressed carrier recombination in the PSCs. Consequently, devices with a champion PCE of 25.22% and a fill factor (FF) close to 85% is achieved, marking the highest PCE and FF observed for PSCs based on CBD TiO2. The unencapsulated device maintained 81.3% of its initial PCE after operating for 1000 h. [ABSTRACT FROM AUTHOR]

Perovskite solar cells are increasingly acknowledged for their unique characteristics. This study focuses on simulating the impact of methylammonium lead bromide‐based perovskites, as the absorber in perovskite solar cells using the SCAPS‐1D simulator. The research delves into how the performance of these solar cells is affected by the choice of Electron Transport Layers (TiO2, PCBM, SnO2, and ZnO) and Hole Transport Layer (Cu2O) with Ni and Al as the back and front contact. This investigation marks the first comprehensive exploration of CH3NH3PbBr3. The performance of these device architectures is significantly influenced by factors such as defect density, absorber thickness, ETL thickness, and the combination of different ETLs. The power conversion efficiencies of devices optimized with TiO2, PCBM, SnO2, and ZnO are found to be 15.46%, 15.33%, 15.01%, and 14.99%, respectively. Furthermore, this study elucidates the impact of absorber and HTL thickness. Also, they have discussed the VBO, CBO for different ETLs. Additionally, the effects of series resistance, shunt resistance are examined, operating temperature, quantum efficiency (QE), capacitance‐voltage characteristics, generation and recombination rates, current density‐voltage (J‐V), and impedance analysis of the devices. Through this extensive simulation study, researchers are equipped to develop cost‐effective and highly efficient PSCs, thereby advancing solar technology. [ABSTRACT FROM AUTHOR]

A homogenous and well-packed electron transport layer (ETL) is crucial in attaining high-performance perovskite solar cells (PSCs). Two vital tasks are carried out by ETL: excellent electron collection, and proficiently prevents the recombination of charge carriers. Hole transport layer (HTL) free screen-printed carbon-based perovskite solar cells (SP-C-PSCs) are particularly favored within the realm of PSCs due to their exceptional scalability, durability, and affordability. Titanium dioxide (TiO2) has been widely used as the ETL in these SP-C-PSCs due to its suitable band energy structure, ease of production, and low cost; nevertheless, it must be of high quality and uniformly deposited. Here experimental analytical study of PSCs was conducted, employed surface passivation to compact titania (c-TiO2) ETL using TiCl4 passivation agent through two different deposition techniques. This passivation is applied to lower its surface roughness, improve electron transport capability, increase crystallinity, reduce micro pores, exhibit better energy level alignment, and to reduce the recombination sites. Consequently, the device with surface passivation enhances the power conversion efficiency (PCE) and long-term ambient stability of PSCs by maximizing the c-TiO2 ETL electrical characteristics. It is also discovered that the passivated c-TiO2 layer has increased hydrophobicity and reduced the RMS surface roughness from 28.8 to 27.3 nm. The PCE of the fabricated SP-C-PSCs is improved by 32.34% through applying spin-coating TiCl4 passivation, and 21.74% enhancement is recorded by applying dip-coating TiCl4 passivation. Furthermore, after 1344 h of storage under ambient conditions without encapsulation, the device passivated with spin-coating retained 84.27%, the device passivated with dip-coating maintained 85.50%, while the reference device reserved just 75.84% PCE. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) systems are regarded as clean and sustainable energy sources and exhibit minimal pollution during their lifetime. The production of hazardous contaminants contaminating water resources, emissions of air pollutants during the manufacturing process, and the impact of PV installations on land use are important environmental factors to consider. The present study aimed to synthesise the F-doped Titanium dioxide (TiO2) thin films on a glass substrate employing spin coating followed by the sol-gel process ETL application purpose. Fluorine-doped TiO2 thin films were prepared using the sol-gel spin coating technique. The X-ray diffraction (XRD) results confirmed that the most intense peak was observed at 25.37° corresponding to the crystallographic plane (101) for anatase TiO2. The average transparency of TiO2 was increased by adding the doping level of fluorine and increment in the optical bandgap. The thickness of the thin film was kept at about 300 nm. The resistance of nanocrystalline thin films of different F doped TiO2 was decreased from 1.322×1012 O, 9.728×1011 O, as the F doping concentration was increased from pristine to 7 at. %. Based on electrical measurements, it was observed that a suitable electron transport layer (ETL) of F-doped TiO2 can be synthesized for photovoltaic applications. The present study offers a synthesis and analysis of F-doped TiO2 that can be used to improve the sustainability of PV manufacturing processes, improve its economic value, and mitigate its negative impact on the environment. [ABSTRACT FROM AUTHOR]

A homogenous and well-packed electron transport layer (ETL) is crucial in attaining high-performance perovskite solar cells (PSCs). Two vital tasks are carried out by ETL: excellent electron collection, and proficiently prevents the recombination of charge carriers. Hole transport layer (HTL) free screen-printed carbon-based perovskite solar cells (SP-C-PSCs) are particularly favored within the realm of PSCs due to their exceptional scalability, durability, and affordability. Titanium dioxide (TiO2) has been widely used as the ETL in these SP-C-PSCs due to its suitable band energy structure, ease of production, and low cost; nevertheless, it must be of high quality and uniformly deposited. Here experimental analytical study of PSCs was conducted, employed surface passivation to compact titania (c-TiO2) ETL using TiCl4 passivation agent through two different deposition techniques. This passivation is applied to lower its surface roughness, improve electron transport capability, increase crystallinity, reduce micro pores, exhibit better energy level alignment, and to reduce the recombination sites. Consequently, the device with surface passivation enhances the power conversion efficiency (PCE) and long-term ambient stability of PSCs by maximizing the c-TiO2 ETL electrical characteristics. It is also discovered that the passivated c-TiO2 layer has increased hydrophobicity and reduced the RMS surface roughness from 28.8 to 27.3 nm. The PCE of the fabricated SP-C-PSCs is improved by 32.34% through applying spin-coating TiCl4 passivation, and 21.74% enhancement is recorded by applying dip-coating TiCl4 passivation. Furthermore, after 1344 h of storage under ambient conditions without encapsulation, the device passivated with spin-coating retained 84.27%, the device passivated with dip-coating maintained 85.50%, while the reference device reserved just 75.84% PCE. [ABSTRACT FROM AUTHOR]

The materials for electron transport layers (ETLs) play a significant role in the performance of polymer solar cells (PSCs) but face challenges, such as low electron transport mobility and conductivity, low solution processibility, and extreme thickness sensitivity, which will undermine the photovoltaic performance and hinder compatibility of large‐scale fabrication technique. To address these challenges, a new n‐type perylene diimide‐based molecule (PDINB) with two special amine‐anchored long‐side chains is designed and synthesized feasibly. PDINB shows very high solubility in common organic solvents, such as dichloromethane (>75 mg ml−1) and methanol with acetic acid as an additive (>37 mg ml−1), which leads to excellent film formability when deposited on active layers. With PDINB as ETLs, the photovoltaic performance of the PSCs is boosted comprehensively, leading to power conversion efficiency (PCE) up to 18.81%. Thanks to the strong self‐doping effect and high conductivity of PDINB, it displays an appreciable thickness‐tolerant property as ETLs, where the devices remain consistently high PCE values with the thickness varying from 5 to 30 nm. Interestingly, PDINB can be used as a generic ETL in different types of PSCs including non‐fullerene PSCs and all‐polymer PSCs. Therefore, PDINB can be a potentially competitive candidate as an efficient ETL for PSCs. [ABSTRACT FROM AUTHOR]

Maintaining the power conversion efficiency (PCE) of perovskite solar cells (PSCs) while enlarging the active area is necessary for their industrialization, where the key part is the uniform carrier extraction. Here, a conformal electron transport layer (ETL) is reported with eliminated low‐conductive contacts through a tailored deposition that combines chemical bath deposition and modified spin‐coating on a light‐managing textured substrate. The KPFM and C‐AFM are utilized to prove the uniform and optimized electrical properties. This study further employs the 2D measurements of PL and TRPL mapping to focus on revealing the enhanced uniformity of electron extraction. The uniform ETL conductivity and electron extraction contribute to a substantial decrease in device up‐scaling losses, making the δPCE (PCE0.08−PCE1PCE0.08)$\frac{{{\mathrm{PC}}{{{\mathrm{E}}}_{0.08}} - {\mathrm{PC}}{{{\mathrm{E}}}_1}}}{{{\mathrm{PC}}{{{\mathrm{E}}}_{0.08}}}})\ $ between 0.08 cm2‐device and 1 cm2‐device decrease from 5.02% to 2.97%, while the perovskite film is deposited using two‐step method. When using one‐step method to deposit perovskite film, PCEs of 25.13% and 23.93% for the active area of 0.08 cm2 and 1 cm2 are achieved, and the δPCE decreases from 7.89% to 4.77%, validating the significant effects on reducing up‐scaling losses. This work provides a new perspective to maintain high efficiency while device up‐scaling, providing more opportunities to push forward the PSCs industrialization. [ABSTRACT FROM AUTHOR]

Planar perovskite solar cells (PSCs), as a promising photovoltaic technology, have been extensively studied, with strong expectations for commercialization. Improving the power conversion efficiency (PCE) of PSCs is necessary to accelerate their practical application, in which the electron transport layer (ETL) plays a key part. Herein, a single-anchored ligand of phenylphosphonic acid (PPA) is utilized to regulate the chemical bath deposition of a TiO2 ETL, further improving the PCE of planar PSCs. The PPA possesses a steric benzene ring and a phosphoric acid group, which can inhibit the particle aggregation of the TiO2 film through steric hindrance, leading to optimized interface (ETL/perovskite) contact. In addition, the incorporated PPA can induce the upshift of the Fermi-level of the TiO2 film, which is beneficial for interfacial electron transport. As a consequence, the PSCs with PPA-TiO2 achieve a PCE of 24.83%, which is higher than that (24.21%) of PSCs with TiO2. In addition, the unencapsulated PSCs with PPA-TiO2 also exhibit enhanced stability when stored in ambient conditions. [ABSTRACT FROM AUTHOR]

This paper reports five novel PDI dimer type electron transport materials (ETMs) employing o‐indoloquinoxaline (o‐Iq), m‐indoloquinoxaline (m‐Iq), and cibalackrot (Ci) groups as the core building blocks and presents the twisted structures of PDI dimers coded as PDI‐NHR‐o‐Iq, PDI‐o‐Iq, PDI‐NHR‐m‐Iq, PDI‐m‐Iq and PDI‐NHR‐Ci dyes (see Scheme 1 and 2). We have systematically compared their photophysical, electrochemical, and optoelectronic properties with respect to the reference dye (2PDI‐NHR), which is directly connected of two PDI planes. Their calculated HOMO‐LUMO energy levels are sufficient for charge transfer to the perovskite material so that structure‐photovoltaic performance relationship of synthesized ETM dyes can be evaluated. When the binding position of indoloquinoxaline group between PDI rings are changed from o‐ to m‐ positions, most of the photophysical and electrochemical properties of PDI dimer are dramatically changed, finally improving the photovoltaic performances. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs), which are constructed using organic–inorganic combination resources, represent an upcoming technology that offers a competitor to silicon-based solar cells. Electron transport materials (ETMs), which are essential to PSCs, are attracting a lot of interest. In this section, we begin by discussing the development of the PSC framework, which would form the foundation for the requirements of the ETM. Because of their exceptional electronic characteristics and low manufacturing costs, perovskite solar cells (PSCs) have emerged as a promising proposal for future generations of thin-film solar energy. However, PSCs with a compact layer (CL) exhibit subpar long-term reliability and efficacy. The quality of the substrate beneath a layer of perovskite has a major impact on how quickly it grows. Therefore, there has been interest in substrate modification using electron transfer layers to create very stable and efficient PSCs. This paper examines the systemic alteration of electron transport layers (ETLs) based on electron transfer layers that are employed in PSCs. Also covered are the functions of ETLs in the creation of reliable and efficient PSCs. Achieving larger-sized particles, greater crystallization, and a more homogenous morphology within perovskite films, all of which are correlated with a more stable PSC performance, will be guided by this review when they are developed further. To increase PSCs' sustainability and enable them to produce clean energy at levels previously unheard of, the difficulties and potential paths for future research with compact ETLs are also discussed. [ABSTRACT FROM AUTHOR]

Metal‐halide perovskite solar cells (PSCs) have emerged as a promising photovoltaic technology. Fabricating PSCs in ambient air can accelerate their low‐cost commercialization, since it can remove the reliance on atmosphere‐controlled equipment. However, the power conversion efficiency (PCE) of air‐fabricated PSCs still lags behind those fabricated in glovebox. Here, based on a technology to fabricate high‐quality perovskite film in ambient air, a compatible optimization is performed on electron transport layer (ETL) to further enhance the photovoltaic performance of PSCs. A soft‐templated deposition strategy is proposed that utilizes tetrasodium glutamate diacetate (GLDA) to finely regulate the chemical bath deposition process, leading to an ideal SnO2 ETL with no additive residual. Adopting this feature of no residual, a molecular bridge using β‐guanidinopropionic acid (βA) is constructed at the buried interface (SnO2/perovskite), which effectively enhances the electron extraction and decreases electron losses. The resulting PSCs (0.08 cm2) achieve an impressive PCE of 25.74% (certificated 25.43%), which is the highest among the air‐fabricated PSCs reported to date. A PCE of 24.61% in 1 cm2‐PSCs is also obtained, exhibiting the scalable potential of the technology. In addition, the excellent operational stability of these PSCs is also demonstrated. [ABSTRACT FROM AUTHOR]

PbS quantum dot (QD) infrared (IR) solar cells that can absorb low‐energy photons are promising photovoltaic devices to improve utilization of sunlight energy by broadening absorption range of the sunlight spectrum to short‐wave infrared region. For PbS QD photovoltaics, depleted heterojunction established between photoactive layer and ZnO electron transport layer (ETL) is critical to determine the performance of devices. However, undesired defects in ZnO films and mismatched energy levels have limited the improvement of device properties. Herein, a novel and simple gradient ZnO ETL is developed for achieving high‐performance QD IR solar cells by depositing a Cs‐doped ZnO thin layer on the pristine ZnO film. The resulting gradient ETL exhibits significantly suppressive trap states and a much smoother surface, efficiently reducing the trap‐assisted nonradiative recombination at the interfaces. Meanwhile, realigned energy levels of the gradient ZnO ETL facilitate the transport and extraction of photogenerated carriers. As a result, the champion device shows a high IR open circuit voltage (VOC) of 0.446 V and IR power conversion efficiency (PCE) of 1.27% under 1100 nm filtered illumination. The VOC and PCE are 0.507 V and 11.04% under AM1.5 illumination, respectively. These results demonstrate a promising strategy for exploiting high‐performance infrared optoelectronic devices. [ABSTRACT FROM AUTHOR]

This investigation initiated by modelling the crystal structure of perovskite to explore the impact of different temperatures. Researchers modified the perovskite crystal structure and observed its response to temperature variations. The study involved assessing the efficiency and fill factor of perovskite solar cells, incorporating photovoltaic structures without specifying the electron transport layer material. The primary goal of this initiative is to provide power to buildings using environmentally acceptable components in perovskite solar cells. The promising efficiency and cost-effectiveness of manufacturing make perovskite solar cells an intriguing option for generating clean and sustainable energy. [ABSTRACT FROM AUTHOR]

At present, heavy-metal-free quantum dot light-emitting diodes (QLEDs) have shown great potential as a research hotspot in the field of optoelectronic devices. This article reviews the research on heavy-metal-free quantum dot (QD) materials and light-emitting diode (LED) devices. In the first section, we discussed the hazards of heavy-metal-containing quantum dots (QDs), such as environmental pollution and human health risks. Next, the main representatives of heavy-metal-free QDs were introduced, such as InP, ZnE (E=S, Se and Te), CuInS2, Ag2S, and so on. In the next section, we discussed the synthesis methods of heavy-metal-free QDs, including the hot injection (HI) method, the heat up (HU) method, the cation exchange (CE) method, the successful ionic layer adsorption and reaction (SILAR) method, and so on. Finally, important progress in the development of heavy-metal-free QLEDs was summarized in three aspects (QD emitter layer, hole transport layer, and electron transport layer). [ABSTRACT FROM AUTHOR]

Highlights: Developing a universal strategy of the p–n homojunction engineering that could significantly boost electron mobility of electron transport layer (ETL) by two orders of magnitude. Proposing a new mechanism based on p–n homojunction to explain inhibited carrier loss at buried interface. Setting a new performance benchmark as high as 25.50% for planar perovskite solar cells employing TiO2 as ETLs. Low-temperature processed electron transport layer (ETL) of TiO2 that is widely used in planar perovskite solar cells (PSCs) has inherent low carrier mobility, resulting in insufficient photogenerated electron transport and thus recombination loss at buried interface. Herein, we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO2 ETL to accelerate electron transport in PSCs, through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude. Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO2 ETL, but the fabrication of perovskite films with larger-grain and the less-trap-states. The embedded p–n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs, favoring for the reduced voltage deficit of PSCs. Benefiting from these merits, the formamidinium lead iodide (FAPbI3) PSCs employing such ETLs deliver a champion efficiency of 25.50%, along with much-improved device stability under harsh conditions, i.e., maintain over 95% of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h, as well as mixed-cation PSCs with a champion efficiency of 22.02% and over 3000 h of ambient storage under humidity stability of 40%. Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics. [ABSTRACT FROM AUTHOR]

Titanium dioxide ( TiO 2 ) is a commonly employed electron transport layer in perovskite solar cells (PSCs) due to its exceptional attributes such as high mobility, a wide bandgap and remarkable stability against moisture and high temperatures. This holds particularly true for inorganic PSCs. Nevertheless, the substantial hysteresis and elevated trap defect levels following annealing present challenges to enhance the efficiency of the PSCs. Herein, we proposed a chemical bath deposition (CBD) method to fabricate the TiO 2 layer, serving as the electron transport layer in CsPbBr 3 solar cells. This method is coupled with KCl, which supplies an ample quantity of K ions capable of diffusing into the CsPbBr 3 perovskite film during the annealing process. The inclusion of K ions significantly diminishes the solar cell hysteresis and enhances the crystalline quality of the perovskite material, thereby enhancing the performance of CsPbBr 3 solar cells. By implementing the TiO 2 and KCl treatments, we achieved an impressive efficiency of 9.49%. Furthermore, the device also exhibited excellent stability in air for 30 days. We introduced KCl as a buffer layer to improve the quality of the TiO 2 films, which was used as the electron transport layer in CsPbBr 3 perovskite solar cells. This strategic addition of K ions serves not only to alleviate hysteresis in the perovskite solar cells, but also to enhance the crystallinity of the perovskite material. These cells have achieved an impressive champion efficiency of 9.49%, while maintaining their performance for over 30 days in ambient conditions. [ABSTRACT FROM AUTHOR]

Context: Density functional theory (DFT) calculations are carried out on pure and doped rutile TiO 2 . The bandgap (E g ) for pristine, S-doped, Fe-doped, and Fe/S co-doped materials is direct, with values of 2.98 eV, 2.18 eV, 1.58 eV, and 1.40 eV. The effective mass of charge carriers (m*) and ratio of effective masses of holes to effective masses of electrons (R) are also investigated, and it is discovered that Fe/S co-doped materials have the lowest charge carrier recombination rate. The Fe/S co-doped material has the highest ε (ω) . α (ω) of doped materials shifted into the visible range. Due to the high dopant concentration in Fe and Fe/S-doped cases, the E g is lowered to a relatively small value; hence, only pristine and S-doped materials are verified as electron transport layer (ETL). A solar cell device analysis employing pure and S-doped rutile TiO 2 as ETL is completed using DFT-derived parameters in SCAPS-1D modeling software for the first time. For the optimized solar cells, current–voltage (IV) characteristics, quantum efficiency (QE), capacitance-voltage (CV) characteristics, and capacitance-frequency (Cf) characteristics are provided. The aim of the present study is to improve efficiency of perovskite solar cell by doping as well as to improve accuracy of simulation by applying DFT extracted parameters as input. From the analysis, improvement is found in efficiency of doped TiO 2 compared to un-doped TiO 2 . The efficiency of the PSC with S-doped ETL is 1.418% higher than the PSC with un-doped ETL. Method: Quantumwise Automistic Tool Kit (ATK) is used to extract DFT parameters. Using these DFT parameters as input in SCAPS-1D (Solar Cell Capacitance Simulator), solar cells for doped and un-doped material are simulated. The density functional theory (DFT)-based orthogonalized linear combination of atomic orbital (OLCAO) technique is used. Structural optimization is done using the LBFGS (Limited-memory Broyden-Fletcher-Goldfarb-Shanno). PBESol-GGA (Perdew-Burke-Ernzerhof solid-generalized gradient approximation) is applied as exchange correlation for calculating structural parameters, while MGGA-TB09 (meta-generalized gradient approximation-Tran and Blaha) is applied as exchange correlation for calculating optical and electronic properties. [ABSTRACT FROM AUTHOR]

Compared to organic–inorganic hybrid perovskites, the cesium‐based all‐inorganic lead halide perovskite (CsPbI3) is a promising light absorber for perovskite solar cells owing to its higher resistance to thermal stress. Nonetheless, additional research is required to reduce the nonradiative recombination to realize the full potential of CsPbI3. Here, the diffusion of Cs ions participating in ion exchange is proposed to be an important factor responsible for the bulk defects in γ‐CsPbI3 perovskite. Calculations based on first‐principles density functional theory reveal that the [PbI6]4− octahedral tilt modifies the perovskite crystallographic properties in γ‐CsPbI3, leading to alterations in its bandgap and crystal strain. In addition, by substituting amorphous barium titanium oxide (a‐BaTiO3) for TiO2 as the electron transport layer, interfacial defects caused by imperfect energy levels between the electron transport layer and perovskite are reduced. High‐resolution transmission electron microscopy and electron energy loss spectroscopy demonstrate that a‐BaTiO3 forms entirely as a single phase, as opposed to Ba‐doped TiO2 hybrid nanoclusters or separate domains of TiO2 and BaTiO3 phases. Accordingly, inorganic perovskite solar cells based on the a‐BaTiO3 electron transport layer achieved a power conversion efficiency of 19.96%. [ABSTRACT FROM AUTHOR]

Electron transport layer (ETL) is a crucial part for perovskite solar cells (PSCs). However, leakage current and oxygen vacancies result from little pores grown from sol‐gel method would inevitably deteriorate the performance of ETL. In contrast, thin films prepared by chemical bath deposition (CBD) could significantly restrain the little cracks. Here, SnO2 ETL are prepared by optimized CBD process, sodium citrate (SC) is explored as an auxiliary reagent to disperse ETL, thus enhances the smoothness and conductivity of the ETL, resulting in a pore‐free flat surface morphology and decreased oxygen vacancy, which is favorable for electron transport and deposition of perovskite (PVK). The PVK film fabricated on the oxygen vacancy free substrate demonstrates high quality and decreased defect density, thus effectively prevents the non‐radiative recombination of carriers. As a result, the short‐circuit current (JSC) and open circuit voltage (Voc) of the PSC devices have been obviously improved, leading to increased photoelectric conversion efficiency from 21.03% to 22.04%. Meanwhile, the long‐term and moisture stability have been promoted simultaneously. [ABSTRACT FROM AUTHOR]

Operational stability is the main obstacle to the industrial applications of organic solar cells (OSCs). In this study, different degradation mechanisms under continuous simulated solar radiation are demonstrated for high‐performance non‐fullerene OSCs based on commonly used electron transport materials, i.e., ZnO and SnO2. The ZnO‐induced decomposition pathways of A‐DA'D‐A type non‐fullerene acceptors (NFAs) under UV illumination are unraveled for the first time and related to N‐dealkylation of pyrrole from the core moiety. In the case of SnO2, poor photo‐stability is primarily ascribed to a high density of trap states, which can be diminished by surface modification to achieve better device stability that is comparable with the stability under LED illumination without UV components. With a thorough understanding of the degradation pathways, this study provides valuable guidelines for designing high‐performance and stable non‐fullerene OSCs. [ABSTRACT FROM AUTHOR]

Quantum dot light‐emitting diodes (QLEDs) is one of the most important components in the display field, and different structures have a certain impact on the final performance of the device. Previous QLEDs mainly use ZnO nanocrystals as the electron transport layer (ETL), but the chemical activity of ZnO nanocrystals under electric fields and moisture is not stable enough. To solve this problem, this paper studies the effects of TiO2 films with different thicknesses on the luminescence, current density and external quantum efficiency of QLED devices by using magnetron sputtered TiO2 as a new ETL. The experimental results show that the 50nm TiO2 film achieves the highest external quantum efficiency while maintaining favorable current density and brightness. [ABSTRACT FROM AUTHOR]

Substandard printing quality of electron transport layers (ETLs) always leads to non‐ideal nucleation crystallization and bottom interface contact of the perovskite, followed by the formation of poor‐quality perovskite films with severe heterogeneity, which is the major source of non‐radiative recombination loss and environmental sensitivity of perovskite solar cells (PVSCs). These often result in serious photovoltaic performance loss, significant instability, and negative fabrication reproducibility. Herein, sodium phytate is proposed as a chelating agent for passivating the tin oxide (SnO2) ETLs to enable the stabilization of SnO2 nanoparticles and facilitate the printing of pinhole‐free films, thereby realizing the controlled nucleation crystallization in perovskite precursor. Thus, the printed PVSCs exhibit a champion power conversion efficiency up to 23.77% with negligible hysteresis effect. The unencapsulated devices demonstrate outstanding long‐term stability, which maintains over 80% of their initial efficiency under exposure to atmospheric environment (50% relative humidity) for 1500 hours, and a consistent and centralized distribution of efficiencies across all seasons, indicating their good reproducibility in diverse climatic atmospheres. [ABSTRACT FROM AUTHOR]

Not only can perovskite solar cells be exposed to high temperatures, up to 80 °C, depending on the operating environment, but absorbed energy is lost as heat, so it is important to have thermal stability for commercialization. However, in the case of the recently reported p-i-n structure solar cell, most of the electron and hole transport layers are composed of organic materials vulnerable to heat transfer, so the light absorption layer may be continuously exposed to high temperatures when the solar cell is operated. In this study, we attempted to improve the thermal conductivity of the electron transport layer using phenyl-C61-butyric acid methyl ester (PCBM) containing zinc oxide (ZnO). As a result, the thermal conductivity was improved by more than 7.4% and 23.5% by adding 6.57vol% and 22.38vol% of ZnO to PCBM, respectively. In addition, the insertion of ZnO resulted in changes in the electron transport behavior and energy level of the electron transport layer. As a result, it was confirmed that not only could the temperature stability of the perovskite thin film be improved, but the efficiency of the solar cell could also be improved from 14.12% to 17.97%. [ABSTRACT FROM AUTHOR]

Perovskite solar cell (pero‐SC) has attracted extensive studies as a promising photovoltaic technology, wherein the electron extraction and transfer exhibit pivotal effect to the device performance. The planar SnO2 electron transport layer (ETL) has contributed the recent record power conversion efficiency (PCE) of the pero‐SCs, yet still suffers from surface defects of SnO2 nanoparticles which brings energy loss and phase instability. Herein, we report a localized oxidation embellishing (LOE) strategy by applying (NH4)2CrO4 on the SnO2 ETL. The LOE strategy builds up plentiful nano‐heterojunctions of p‐Cr2O3/n‐SnO2 and the nano‐heterojunctions compensate the surface defects and realize benign energy alignment, which reduces surface non‐radiative recombination and voltage loss of the pero‐SCs. Meanwhile, the decrease of lattice mismatch released the lattice distortion and eliminated tensile stress, contributing to better stability of the devices. The pero‐SCs based on α‐FAPbI3 with the SnO2 ETL treated by the LOE strategy realized a PCE of 25.72 % (certified as 25.41 %), along with eminent stability performance of T90>700 h. This work provides a brand‐new view for defect modification of SnO2 electron transport layer. [ABSTRACT FROM AUTHOR]

The presence of TiO2 used as an efficient electron transport layer is crucial to achieving high-performance solar cells, especially for a hole transport material (HTM)-free carbon-based perovskite solar cell (PSC). The hydrolysis of TiCl4 is one of the most widely used routes for forming TiO2 layer in solar cells, which includes the stock solution preparation from TiCl4 initial precursor and the thermal hydrolysis of the stock solution. The second thermal hydrolysis step has been extensively studied, while the initial hydrolysis reaction in the first step is not receiving sufficient attention, especially for its influence on the photovoltaic performance of HTM-free carbon-based devices. In this study, the role of TiCl4 stock solution in the growth process of TiO2 layer is examined. Based on the analysis of the Ti(IV) intermediate states for different TiCl4 concentrations from Raman spectra, 2 M TiCl4 precursor exhibits moderate nucleation and growth kinetics without generating too many intermediates which occurs in 3 M TiCl4 precursor, yielding ∼300 nm size spherical TiO2 agglomerates with a rutile phase. In the aspect of devices, the HTM-free carbon-based PSCs fabricated using 2 M TiCl4 precursor deliver a conversion efficiency beyond 17%, which may be attributed to the reduced defect in compact TiO2 layer. [ABSTRACT FROM AUTHOR]

In organic solar cells, the interfaces between the photoactive layer and the transport layers are critical in determining not only the efficiency but also their stability. When solution‐processed metal oxides are employed as the electron transport layer, the presence of surface defects can downgrade the charge extraction, lowering the photovoltaic parameters. Thus, understanding the origin of these defects is essential to prevent their detrimental effects. Herein, it is shown that a widely reported and commercially available colloidal SnO2 dispersion leads to suboptimal interfaces with the organic layer, as evidenced by the s‐shaped J–V curves and poor stability. By investigating the SnO2 surface chemistry, the presence of potassium ions as stabilizing ligands is identified. By removing them with a simple washing with deionized water, the s‐shape is removed and the short‐circuit current is improved. It is tested for two prototypical blends, TPD‐3F:IT‐4F and PM6:L8:BO, and for both the power conversion efficiency is improved up to 12.82% and 16.26%, from 11.06% and 15.17% obtained with the pristine SnO2, respectively. More strikingly, the stability is strongly correlated with the surface ions concentration, and these improved devices maintain ≈87% and ≈85% of their initial efficiency after 100 h of illumination for TPD‐3F:IT‐4F and PM6:L8:BO, respectively. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have garnered significant attention in the photovoltaic field owing to their exceptional photoelectric properties, including high light absorption, extensive carrier diffusion distance, and an adjustable band gap. Temperature is a crucial factor influencing both the preparation and performance of perovskite solar cells. The annealing temperature exerts a pronounced impact on the device structure, while the operational temperature influences carrier transport, perovskite band gap, and interface properties. This paper provides a comprehensive review of the influence of varied annealing temperatures on the hole transport layer, electron transport layer, and perovskite layer. Additionally, we present an overview of innovative annealing methods applied to perovskite materials. The effects of diverse working temperatures on the overall performance of perovskite cells are thoroughly examined and discussed in this review. In the end, different temperature conditions under ISOS testing conditions are summarized. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO2) and aluminum-doped zinc oxide (AZO) have been recognized as promising materials for the electron transport layer (ETL) in perovskite solar cells (PSCs) due to their favorable optoelectronic properties and low-temperature deposition processes. However, high surface trap density at the ETL/perovskite interface limits the further improvement of the power conversion efficiency (PCE) of planar PSCs. Herein, we have demonstrated a simple surface treatment of low-temperature deposited SnO2/AZO–ETL through mono-ethanolamine (MEA) to passivate the defects at the AZO/perovskite interface and reduce carrier recombination. Meanwhile, after MEA modification, the defect states at the AZO/perovskite interface were reduced, and the carrier transport capability was improved. PSC based on MEA modification showed an enhanced PCE of 15.73%, compared to 12.66% without MEA treatment, and a fill factor (FF) of 68.30% on a 0.25 cm2 active area. Furthermore, the MEA-passivated device exhibits excellent stability and retains ~ 77% of its initial PCE after 1000 h under ambient storage without encapsulation. Thus, interface engineering based on the mono-ethanolamine passivation provides a feasible and novel strategy to improve the quality of ETL to fabricate high-efficiency planar PSCs. [ABSTRACT FROM AUTHOR]

A small molecular phenanthroline derivative Phen‐NaDPO (3‐[6‐(diphenylphosphinyl)‐2‐naphthalenyl]‐1,10‐Phenanthroline) to modify tin oxide (SnO2) electron‐transport layer (ETL) in organic solar cells is employed. Quantum chemistry calculations and experimental results show that Phen‐NaDPO can interact with SnO2, thereby effectively passivating the surface defects, reducing the work function and improving the electrical conductivity of SnO2, leading to more efficient electron extraction and transport in the organic solar cells (OSCs). Moreover, upon the Phen‐NaDPO modification, the decreased surface energy of SnO2 ETL accounts for enhanced exciton dissociation and charge transport, due to the more ordered molecular organizations of the active layers. Consequently, the inverted OSCs involving Phen‐NaDPO/SnO2 ETLs exhibit an enhanced power conversion efficiency of 17.06% (PM6:Y6) and 18.31% (PM6:L8‐BO), which is the highest efficiency for SnO2 ETL‐based binary solar cells to date. Furthermore, the devices based on Phen‐NaDPO/SnO2 ETL show better device stability (storage stability, photostability and humid stability), with T80 exceeding 200 h encapsulated under light irradiation and 400 h without encapsulation in high‐humidity ambient condition. These results demonstrate that the modification of SnO2 using wide‐band highly stable conjugated small molecules is very promising for simultaneously improve the efficiencies and device stability of OSCs. [ABSTRACT FROM AUTHOR]

Infrared (IR) solar cells are potential optoelectronic devices for boosting the power conversion efficiency (PCE) of conventional photovoltaics (such as pervoskite and silicon solar cells) by broadening the utilization range of the sunlight spectrum to short‐wavelength infrared region. PbSe colloidal quantum dots (QDs) are one of the optimal candidates for IR solar cells because of their tunable bandgap in the IR region and flexible solution processibility. At present, the best PbSe QD IR photovoltaics generally adopt ZnO as an electron transport layer (ETL). However, the intrinsic drawbacks and surface defects of ZnO can potentially deteriorate the PCE of devices. Herein, Ti3C2Tx, a representative 2D transition carbide, is combined with sol‐gel ZnO to develop a new hybrid ETL for fabricating high‐performance IR solar cells. This combination effectively suppresses the defects within ZnO by forming new bondings and simultaneously enhances the crystalline of ZnO film. Meanwhile, the introduction of Ti3C2Tx into ZnO film accelerates the transport and collection of photo‐generated carriers by constructing a new electron transport pathway. Consequently, compared to the bare devices, the infrared PCE of PbSe QD solar cells increases by 19.5% to 1.04%. These results demonstrate that this hybrid ETL can offer a bright approach for developing high‐performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

The toxicity and stability concerns of lead based perovskite solar cells have limited the commercialization. The lead-free Cesium based double perovskite could be a viable answer to these issues. In this present work a theoretical analysis of Cesium based double perovskite solar cell using Spiro-OMeTAD as hole transport layer and effect of different ETLs such as SnO2, ZnO-NR, TiO2 and CdS has been studied. The optimized active layer thickness of 0.3 μm has been used and a device structure of FTO/ETLs/Cs2AgBiBr6/Spiro-OMeTAD/Cu was simulated. The Solar Cell Capacitance Simulator (SCAPS-1D) was used for one dimensional simulation and analysis. The maximum PCE of 5.62 % was found using SnO2 as ETL. The device performance has been optimized by employing various ETLs and the most suitable ETL for this structure was found to be SnO2. The maximum quantum efficiency of 86.09 % has been found for SnO2 electron transport layer. The simulation results obtained in this study are encouraging and will provide insightful guidance in replacing toxic Pb-based perovskite with eco-friendly inorganic perovskite solar cell. [ABSTRACT FROM AUTHOR]

Significant progress has been made in the advancement of perovskite solar cells, but their commercialization remains hindered by their lead-based toxicity. Many non-toxic perovskite-based solar cells have demonstrated potential, such as Cs2AgBi0.75Sb0.25Br6, but their power conversion efficiency is inadequate. To address this issue, some researchers are focusing on emerging acceptor–donor–acceptor'–donor–acceptor (A-DA'D-A)-type non-fullerene acceptors (NFAs) for Cs2AgBi0.75Sb0.25Br6 to find effective electron transport layers for high-performance photovoltaic responses with low voltage drops. In this comparative study, four novel A-DA'D-A-type NFAs, BT-LIC, BT-BIC, BT-L4F, and BT-BO-L4F, were used as electron transport layers (ETLs) for the proposed devices, FTO/PEDOT:PSS/Cs2AgBi0.75Sb0.25Br6/ETL/Au. Comprehensive simulations were conducted to optimize the devices. The simulations showed that all optimized devices exhibit photovoltaic responses, with the BT-BIC device having the highest power conversion efficiency (13.2%) and the BT-LIC device having the lowest (6.8%). The BT-BIC as an ETL provides fewer interfacial traps and better band alignment, enabling greater open-circuit voltage for efficient photovoltaic responses. [ABSTRACT FROM AUTHOR]

The Copper (Cu)-based perovskite materials, (CH3NH3)2CuX4 or (MA)2CuX4 with [X = Cl4, Cl2I2, and Cl2Br2] are explored for use in perovskite solar cells (PSCs). The foremost objectives of this investigation are the optimization and finding the combination of Electron Transport Layer [ETL], Perovskite Absorber Layer (PAL) and the different organic and inorganic Hole Transport Layers [HTLs] for better device performance. The impact of other important functional parameters on the performance of PSCs are also studied. These parameters are, thicknesses of PAL, operating temperature (T), series resistance (RS), and radiative recombination rate under the illuminance of AM1.5. This SCAPS-1D simulation study deduced the optimized value of the thickness for (MA)2CuCl4, (MA)2CuCl2I2 and (MA)2CuCl2Br2 based absorber layer to be 400 nm, 500 nm and 600 nm, respectively at defect density (Nt) of 1 × 1013 cm−3 and 300 K operating temperature. The optimum value of operating temperature is 300 K for all PSCs but for C60/(MA)2CuCl4/Cu2O PSC, optimum value is 320 K at 400 nm of absorber layer. With considerations of all these optimum values, the highest power conversion efficiency of 28.31% has been obtained for the PCBM/(MA)2CuCl2Br2/CuI configuration at operating temperature of 300 K. Thus, the study reveals that PCBM as ETL, while CuI and Cu2O as HTLs are most suitable for the Cu-based PSC. Based upon the comparison with experimental results, our findings are indicative of the fact that traditional charge transport materials like TiO2 and spiro-OMeTAD may not be the best choices for new lead-free Cu-based PSCs. [ABSTRACT FROM AUTHOR]

Perovskite solar cells are an attractive technology for renewable energy production. However, stability issues with the electron transport layer (ETL), particularly the colloidal tin oxide (SnO2) solution, can impact cell efficiency. In this study, a novel acidization treatment is introduced to reactivate long‐time stored SnO2 solutions, which previously led to low‐efficiency perovskite solar cells. The acidization treatment results in enhanced conductivity of the SnO2 layer, improved perovskite film quality, and ultimately increased efficiency. These findings show that a 1‐month stored SnO2 solution treated with acetic acid produces a device with a photoelectric conversion efficiency (PCE) of 20.9%, compared to 13.5% efficiency without treatment. With the addition of PEAI, the champion efficiency of the acetic acid‐treated device is 22.3%. This study provides a simple and effective engineering approach to fabricating high‐performance and stable ETLs for perovskite solar cells. [ABSTRACT FROM AUTHOR]

Environment friendly third-generation solar cells sensitized by dyes, quantum dots, and perovskites are seen as promising energy alternatives. Among the various strategies, employing one-dimensional nanostructures that exemplify the smallest dimension for efficient carrier transport rate from the active layer to electron transport layer (ETL) in photovoltaic devices is attempted in this work. We herein report the synthesis of well-aligned 1-D TiO2 nanocones as ETL for photovoltaic thin films by varying the precursor concentration (0.03 M, 0.04 M, 0.05 M) to track the evolution of growth. The hydrothermal approach is exploited to grow oriented rutile TiO2 nanocones on fluorine doped tin oxide (FTO) under neutral conditions. The examination of phase, crystallinity, morphology, and opto-electronic properties of the well-structured nanocone arrays is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), ultra violet diffuse reflectance spectroscopy (UV-DRS), Brunnauer–Emmett–Teller (BET) surface area analysis, and field-dependent dark and photoconductivity analysis. The XRD pattern confirms the formation of the tetragonal rutile phase. SEM micrographs and UV-DRS spectroscopy reveals that the length of the nanocones and the energy gap is found to be maximum for 0.04 M concentration with a well-defined excitation band at 316 nm. Significantly, a strong light-trapping effect that decreases the incident light reflections and correspondingly increases the light absorption is unveiled through photoconductive studies for the TiO2 nanocones at 0.04 M having a surface area of 81.767 m2/g. The investigation essentially suggests that the as-prepared one-dimensional nanostructures would serve as efficient photoanodes in environment safe third-generation solar cells. [ABSTRACT FROM AUTHOR]