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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]

The planar perovskite solar cells (PSCs) using TiO2 as the electron transport layer (ETL) are undergoing a stagnated efficiency improvement, which the inferior TiO2 ETL mainly limits. Herein, a flocculating‐regulated TiO2 deposition using SnCl2·2H2O is reported as the flocculate to control the nanoparticle size finely for optimizing TiO2 deposition and to achieve a synergistic Sn doping. The SnCl2·2H2O incorporated into bath precursor can bridge‐link the suspended nanoparticles, which promotes the precipitation of large‐sized nanoparticles and leaves the smaller‐sized nanoparticles for deposition, leading to a compact TiO2 film with marked reduced surface roughness. Meanwhile, along with flocculating‐regulated TiO2 deposition, it can also be achieved the Sn‐doping of TiO2, which increases the conductivity of TiO2 thin films by ≈2.5 times. As a consequence, attributing to the optimized interface contact and accelerated interfacial electron transport, the planar PSCs achieved a certification efficiency of 25.85%, the highest value among the TiO2‐based planar PSCs to date. In addition, the PSCs can maintain 99% of their initial efficiency after more than 4500 h of storage in ambient air, showing excellent stability. [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]

In recent studies, flexible perovskite solar cells (PSCs) have exhibited high power conversion efficiency (PCE) coupled with remarkable mechanical stability. However, the conventional polymer substrates used in flexible PSCs possess high permeability to moisture and oxygen, leading to the rapid degradation of perovskite materials. In this work, we address these issues by employing ultrathin glass (UTG) substrates, which provide moisture impermeability while retaining flexibility. Additionally, we introduce a strategically designed SnO2/TiO2 bilayer as the electron transport layer (ETL). Our results reveal that PSCs incorporating the bilayer ETL achieve higher PCE than those with a monolayer ETL on conventional glass and UTG substrates. Furthermore, moisture permeability tests demonstrate that PSCs based on UTG substrates sustain their PCE over time, compared to their polymer-based counterparts. These results imply that UTG substrates, combined with a SnO2/TiO2 bilayer ETL, offer a promising solution for developing durable, high-performance, flexible PSCs suitable for long-term applications. [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]

Comprehensive Summary: Tin oxide (SnO2) has been widely used as an electron transport layer (ETL) in optoelectronic devices. However, there are numerous surface or bulk defects in SnO2, working as charge recombination centers to degrade device. Here, an electroactive and self‐healing polyurethane (PHNN) was designed by integrating conjugated unit – naphthalene diimide (NDI) into a typical polyurethane backbone. Numerous hydrogen bonds and π interactions in PHNN work as non‐covalent interactions to endow this polymer with superior self‐healing properties. PHNN contains lots of aliphatic amine and carbonyl groups, which effectively passivate the defects in SnO2. The π stacking of NDI units will facilitate electron delocalization, endowing PHNN with electrical activity compared with traditional polyurethane. Doping SnO2 with PHNN can improve the conductivity and reduce the work function of SnO2 layer, which is conducive to efficient charge extraction and transport. Using PHNN doped SnO2 as ETL for PM6: Y6 and PM6: BTP‐eC9 based inverted organic solar cells can achieve a high efficiency of 17.16% and 17.51%, respectively. Devices containing doped SnO2 ETL show significantly improved efficiency and stability. Thus, the electroactive polyurethane doped SnO2 interlayers show high performance interfacial modification to align energy‐levels in solar cell devices, which have promising applications in organic electronics. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Tin oxide (SnO2) has been widely used as an electron transport layer (ETL) in optoelectronic devices. However, there are numerous surface or bulk defects in SnO2, working as charge recombination centers to degrade device. Here, an electroactive and self‐healing polyurethane (PHNN) was designed by integrating conjugated unit – naphthalene diimide (NDI) into a typical polyurethane backbone. Numerous hydrogen bonds and π interactions in PHNN work as non‐covalent interactions to endow this polymer with superior self‐healing properties. PHNN contains lots of aliphatic amine and carbonyl groups, which effectively passivate the defects in SnO2. The π stacking of NDI units will facilitate electron delocalization, endowing PHNN with electrical activity compared with traditional polyurethane. Doping SnO2 with PHNN can improve the conductivity and reduce the work function of SnO2 layer, which is conducive to efficient charge extraction and transport. Using PHNN doped SnO2 as ETL for PM6: Y6 and PM6: BTP‐eC9 based inverted organic solar cells can achieve a high efficiency of 17.16% and 17.51%, respectively. Devices containing doped SnO2 ETL show significantly improved efficiency and stability. Thus, the electroactive polyurethane doped SnO2 interlayers show high performance interfacial modification to align energy‐levels in solar cell devices, which have promising applications in organic electronics. [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]

In organic solar cells (OSCs), the electron transport layer (ETL) is vital for high performance devices. As a widely used ETL, N-oxide-functionalized perylene-diimide (PDINO) is often limited by its low conductivity. Herein, we develop an improved ETL by doping indole carbonized polymer dots (CPDs) into PDINO. The graphitic N and oxoindole groups of CPDs could increase the self-doping of PDINO. Compared with the pristine PDINO ETL, the PDINO + CPDs ETL shows a more suitable work function and higher conductivity due to the graphitic nature of CPDs and the enhanced self-doping of PDINO. PM6:Y6 OSCs with a 10 nm PDINO + CPDs ETL demonstrate a superior average power conversion efficiency (PCE) (17.0%) compared with OSCs with only a PDINO ETL (15.6%). This improvement in PCE is attributed to the enhanced efficiency of exciton dissociation and reduced charge recombination within the devices. Furthermore, OSCs utilizing PDINO + CPDs ETL display a notable resilience to variations in ETL thickness, maintaining a high average PCE of 15.0% even when the ETL thickness is increased to 70 nm. This work provides a simple interfacial modification strategy to optimize ETLs for OSCs. [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]

The assessment of electron transport layer (ETL) for rear-contact engineering of silicon (Si) based optoelectronics has been considered as one of the critical challenges that leverage the performance improvement and device reliability. In this work, the hybrid design of ETL, obtained from the solution-processed nitrogen-doped carbon quantum dots (NCQDs) incorporated with organic polyethylenimine (PEI) demonstrates the feasible contact characteristics for the modification of Si/Al contacts, which greatly facilitates the transport and collection of photoexcited electrons in the Si-based optoelectronics. The aspects of microstructures, functional groups, chemical features, interfacial characteristics and band structures of NCQD/PEI are explicated, visualizing that the evolution of interface dipoles mediated by the overall outcome of physisorption and chemisorption effects, modifies the surface potential difference and results in the explicit reduction of the Al work function from 4.3 eV for pristine Al to 3.23 eV based on the optimized constitutional design (0.10 % NCQD in PEI). These findings are practically employed on the Si-based hybrid solar cells at Si/Al interfaces, fulfilling the conversion-efficiency improvement by 30.9 % compared with reference cells without ETL employment, which are experimentally interpreted by the efficient electron transport across the Si/Al heterojunction and charge collection.

Recently, flexible perovskite solar cells (FPSCs) fabricated using solution-processed printing techniques have garnered significant attention. However, challenges remain in achieving cost-effective, scalable manufacturing under ambient conditions and ensuring stable, efficient devices. This study focuses on fabricating printed FPSCs using the slot-die coating technique and examines the impact of SnO2 quantum dot (QD) and (6,6)-Phenyl C61 butyric acid methyl ester (PCBM) based electron transport layers (ETLs) on device performance and hysteresis. Experimentally results show that SnO2 QD-based devices exhibited favorable photovoltaic properties but significant hysteresis compared to PCBM-based devices. Numerical simulations have shown that the hysteresis effect in devices is influenced not only by the higher concentration of mobile ions in the perovskite layer of PCBM-based devices compared to SnO2 QD-based devices, but also by the more effective redistribution of these ions during forward and reverse J-V scans. The results provide insights into the behavior of printed FPSCs with different ETLs, contributing to the development of high-performance, hysteresis-free printed FPSCs.

Abstract Perovskite solar cells (PSCs) have gained much attention in recent years because of their improved energy conversion efficiency, simple fabrication process, low processing temperature, flexibility, light weight, and low cost of constituent materials when compared with their counterpart silicon based solar cells. Besides, stability and toxicity of PSCs and low power conversion efficiency have been an obstacle towards commercialization of PSCs which has attracted intense research attention. In this research paper, a Glass/Cu2O/CH3NH3SnI3/ZnO/Al inverted device structure which is made of cheap inorganic materials, n-type transparent conducting oxide (TCO)-free, stable, photoexcited toxic-free perovskite have been carefully designed, simulated and optimized using a one-dimensional solar cell capacitance simulator (SCAPS-1D) software. The effects of layers’ thickness, perovskite’s doping concentration and back contact electrodes have been investigated, and the optimized structure produced an open circuit voltage (Voc) of 1.0867 V, short circuit current density (JSC) of 33.4942 mA/cm2, fill factor (FF) of 82.88% and power conversion efficiency (PCE) of 30.17%. This paper presents a model that is first of its kind where the highest PCE performance and eco-friendly n-type TCO-free inverted CH3NH3SnI3 based perovskite solar cell is achieved using all-inorganic transport materials.

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.

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]

Lead-free potassium titanium halide (K2TiI6) perovskite is considered a substantial alternative for highly efficient perovskite solar cells. This research consists of a computational study of Pb-free K2TiI6-based perovskite solar cell using SCAPS 1D. Primarily, the TiO2 and PEDOT:PSS are considered as ETL and HTL exhibit a device efficiency of 5.70%. Further, the impact of various ETL and HTL is explored. The optimization is mainly focused on considering its built-in potential relation with the open circuit voltage and its device efficiency. It is obtained from the numerical simulation, that to circumvent the VOC loss, the CB minimum of the PVSK(CBmin_PVSK) layer should be higher than the CB minimum of the ETL (CBmin_ETL), and the CB minimum of the ETL (CBmin_ETL) should either align or lie above than the FTO contact. In order to have proper hole transport from the perovskite, the VB maximum of the perovskite (PVSK) layer should be lower than the VB maximum of HTL and should either align or lie below the back contact. It is obtained from the simulation that the optimized ETL and HTLs are found as PCBM and Sr2Cu2O2 improve the device efficiency. Further, the impact of perovskite thickness is also investigated, which enhances the device efficiency up to 23.75%. The proposed structure shows remarkable PV parameters VOC = 1.32 V, JSC = 22.30 mA/cm2, FF = 81.07%, and ƞ = 24.01% which indicates that the K2TiI6-based perovskite solar cell is considered a remarkable candidate for Pb-free perovskite solar cell development. [ABSTRACT FROM AUTHOR]

This study investigated the fabrication and characterization of CH3NH3PbI3 based perovskite solar cells (PSCs) using the one-step spin coating technique under ambient conditions, eliminating the need for expensive glovebox and thermal evaporation equipment. The perovskite layer was annealed at 65 °C for 30 seconds and 100 °C for 30 seconds, 1 and 2 minutes. The scanning electron microscope (SEM) images show a smooth and uniform surface coverage for the ETL and CH3NH3PbI3 layers. SEM results also show an average grain size of 397 nm for CH3NH3PbI3 and an average particle size of ~17 nm for TiO2 was confirmed by transmission electron microscopy (TEM). X-ray diffraction (XRD) results confirmed the formation of tetragonal perovskite (CH3NH3PbI3) phase with high crystallinity with a crystallite size of 19.99 nm for the samples annealed for 30 seconds at 65 °C and 1 min at 100 °C. FTIR results also confirmed the presence of anatase TiO2 at wavenumber 438 cm-1 and the formation of the adduct of Pb2 with dimethyl sulfoxide (DMSO) and MAI is confirmed at 1,015 cm-1. From the Tauc plot the bandgap energy of TiO2 and Perovskite layers was determined to be 3.52 eV and 2.06 eV respectively. An open-circuit voltage was 0.9057 V and short circuit current density was 12.2185 mA/cm² with a fill factor of 48.05 and power conversion efficiency (PCE) of 5.199%. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have gained much attention in recent years because of their improved energy conversion efficiency, simple fabrication process, low processing temperature, flexibility, light weight, and low cost of constituent materials when compared with their counterpart silicon based solar cells. Besides, stability and toxicity of PSCs and low power conversion efficiency have been an obstacle towards commercialization of PSCs which has attracted intense research attention. In this research paper, a Glass/Cu2O/CH3NH3SnI3/ZnO/Al inverted device structure which is made of cheap inorganic materials, n-type transparent conducting oxide (TCO)-free, stable, photoexcited toxic-free perovskite have been carefully designed, simulated and optimized using a one-dimensional solar cell capacitance simulator (SCAPS-1D) software. The effects of layers' thickness, perovskite's doping concentration and back contact electrodes have been investigated, and the optimized structure produced an open circuit voltage (Voc) of 1.0867 V, short circuit current density (JSC) of 33.4942 mA/cm2, fill factor (FF) of 82.88% and power conversion efficiency (PCE) of 30.17%. This paper presents a model that is first of its kind where the highest PCE performance and eco-friendly n-type TCO-free inverted CH3NH3SnI3 based perovskite solar cell is achieved using all-inorganic transport materials. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO), a material with excellent electron mobility and a low-temperature requirement for production, is a promising option for use as an electron transport layer in perovskite solar cells (PSCs). However, it does have the drawback of having a low open-circuit voltage (VOC). Herein, to increase the VOC parameter of ZnO-based PSCs, graphene quantum dots (GQDs) are incorporated into the ZnO precursor and used as desirable ETL for PSCs. The presence of GQDs in ZnO ETL facilitated photo-electrons at the ETL/perovskite interface by reducing charge transfer resistance in this interface. Compared to the net ZnO-based PSCs, solar cells using GQD-doped ZnO as ETL have better stability, comparable JSC, higher VOC, and FF. The best GQD-doped-ZnO ETL-based PSCs recorded the highest power conversion efficiency of 20.23% with VOC of 1.130V. Meanwhile, the boosted PCE of FAPbI3-based PSCs is achieved due to the improved perovskite crystal quality, the effective defect passivation effect of GQDs at ZnO/FAPbI3 interface, and the increased electrical conductivity of ZnO ETL. In addition, the GQD-doped ETL devices showed higher ambient air stability than the devices with net ZnO ETLs. [ABSTRACT FROM AUTHOR]