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Molecular engineering of highly efficient dopant-free spiro-type hole transporting materials for perovskite solar cells
摘要： Up to now, the most efficient perovskite solar cells (PSCs) typically utilize Spiro-OMeTAD as hole transporting materials (HTMs). The unique “spiro” structure offers appropriate energy levels for hole transfer and high thermal stability with suppressed aggregation. However, the pristine Spiro-OMeTAD requires additional oxidizing dopants to work efficiently due to its low hole mobility. To retain the advantages of spiral structure and overcome its shortcomings, we demonstrate the design of three dopant-free HTMs with spiral structure by molecular engineering, in which three groups with different conjugated lengths, namely benzene, naphthalene and anthracene, are inserted between spiral core and electron donor. These designed molecules, Y-1~Y-3, are initially identified with quantum chemical calculations based on the mother molecule X59 and then are obtained by easy synthetic routes. Our studies show that the intramolecular charge transfer (ICT) states are formed in the designed molecules due to the introduction of conjugated groups, which produces a self-doping effect without the need to add any external dopant. The best-performing PSCs using the dopant-free Y-1 as HTM achieves a champion power conversion efficiency (PCE) of 16.29% under one sun illumination, which is higher than that of devices with X59 as dopant-free HTMs (14.64%). The present work provides an effective strategy for designing, synthesizing of highly efficient and stable dopant-free HTMs.
关键词： Perovskites solar cells,Dopant-free,Hole-transporting materials,Quantum chemical calculations,Spiral structure
更新于2025-09-23 15:19:57
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Boosting Performance of Nona??Fullerene Organic Solar Cells by 2D ga??C <sub/>3</sub> N <sub/>4</sub> Doped PEDOT:PSS
摘要： The power-conversion efficiency (PCE) of single-junction organic solar cells (OSCs) has exceeded 16% thanks to the development of non-fullerene acceptor materials and morphological optimization of active layer. In addition, interfacial engineering always plays a crucial role in further improving the performance of OSCs based on a well-established active-layer system. Doping of graphitic carbon nitride (g-C3N4) into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a hole transport layer (HTL) for PM6:Y6-based OSCs is reported, boosting the PCE to almost 16.4%. After being added into the PEDOT:PSS, the g-C3N4 as a Bronsted base can be protonated, weakening the shield effect of insulating PSS on conductive PEDOT, which enables exposures of more PEDOT chains on the surface of PEDOT:PSS core-shell structure, and thus increasing the conductivity. Therefore, at the interface between g-C3N4 doped HTL and PM6:Y6 layer, the charge transport is improved and the charge recombination is suppressed, leading to the increases of fill factor and short-circuit current density of devices. This work demonstrates that doping g-C3N4 into PEDOT:PSS is an efficient strategy to increase the conductivity of HTL, resulting in higher OSC performance.
关键词： hole-transport layers,PEDOT:PSS,organic solar cells,g-C3N4,non-fullerene acceptors
更新于2025-09-23 15:19:57
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Arbitrary control of the diffusion potential between a plasmonic metal and a semiconductor by an angstrom-thick interface dipole layer
摘要： Localized surface plasmon resonances (LSPRs) are gaining considerable attention due to the unique far-field and near-field optical properties and applications. Additionally, the Fermi energy, which is the chemical potential, of plasmonic nanoparticles is one of the key properties to control hot-electron and -hole transfer at the interface between plasmonic nanoparticles and a semiconductor. In this article, we tried to control the diffusion potential of the plasmonic system by manipulating the interface dipole. We fabricated solid-state photoelectric conversion devices in which gold nanoparticles (Au-NPs) are located between strontium titanate (SrTiO3) as an electron transfer material and nickel oxide (NiO) as a hole transport material. Lanthanum aluminate as an interface dipole layer was deposited on the atomic layer scale at the three-phase interface of Au-NPs, SrTiO3, and NiO, and the effect was investigated by photoelectric measurements. Importantly, the diffusion potential between the plasmonic metal and a semiconductor can be arbitrarily controlled by the averaged thickness and direction of the interface dipole layer. The insertion of an only one unit cell (uc) interface dipole layer, whose thickness was less than 0.5 nm, dramatically controlled the diffusion potential formed between the plasmonic nanoparticles and surrounding media. This is a new methodology to control the plasmonic potential without applying external stimuli, such as an applied potential or photoirradiation, and without changing the base materials. In particular, it is very beneficial for plasmonic devices in that the interface dipole has the ability not only to decrease but also to increase the open-circuit voltage on the order of several hundreds of millivolts.
关键词： interface dipole,Fermi energy,strontium titanate,nickel oxide,hole transfer,hot-electron,lanthanum aluminate,gold nanoparticles,photoelectric conversion,Localized surface plasmon resonances
更新于2025-09-23 15:19:57
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Effects of Annealing on Characteristics of Cu2ZnSnSe4/CH3NH3PbI3/ZnS/IZO Nanostructures for Enhanced Photovoltaic Solar Cells
摘要： This paper presents new photovoltaic solar cells with Cu2ZnSnSe4/CH3NH3PbI3(MAPbI3)/ZnS/IZO/Ag nanostructures on bi-layer Mo/FTO (fluorine-doped tin oxide) glass-substrates. The hole-transporting layer, active absorber layer, electron-transporting layer, transparent-conductive oxide layer, and top electrode-metal contact layer, were made of Cu2ZnSnSe4, MAPbI3 perovskite, zincsulfide, indium-doped zinc oxide, and silver, respectively. The active absorber MAPbI3 perovskite film was deposited on Cu2ZnSnSe4 hole-transporting layer that has been annealed at different temperatures. TheseCu2ZnSnSe4 filmsexhibitedthe morphology with increased crystal grain sizesand reduced pinholes, following the increased annealing temperature. When the perovskitefilm thickness was designed at 700 nm, the Cu2ZnSnSe4 hole-transporting layer was 160 nm, and the IZO (indium-zinc oxide) at 100 nm, and annealed at 650°C, the experimental results showed significant improvements in the solar cell characteristics. The open-circuit voltage was increased to 1.1 V, the short-circuit current was improved to 20.8 mA/cm2, and the device fill factor was elevated to 76.3%. In addition, the device power-conversion efficiency has been improved to 17.4%. The output power Pmax was as good as 1.74 mW and the device series-resistance was 17.1 ?.
关键词： IZO,hole-transporting material,perovskite,CZTSe,magnetron sputtering
更新于2025-09-23 15:19:57
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High-performance green light-emitting diodes based on MAPbBr <sub/>3</sub> with ??-conjugated ligand
摘要： The morphology, crystal size, and trap density of perovskite films significantly affect the luminescent properties of perovskite light-emitting diodes (PeLEDs). Recently, numerous studies have been conducted on ligands that surround the surface of perovskite crystals and passivate the trap sites to improve the performance of PeLEDs. In this study, a 4-aminobenzonitrile (ABN) ligand improved the performance of methylammonium lead bromide (MAPbBr3)-based PeLEDs by reducing the MAPbBr3 crystal size to the nanoscale and reducing the trap density. Moreover, the properties of PeLEDs with ABN were further improved using a surface-modified hole-transport layer (HTL) with a hydrophilic polymer. Finally, a bright green PeLED was fabricated and exhibited the maximum luminance of 3350 cd/m2 with an external quantum efficiency of 8.85%. Therefore, it is believed that the use of proper ligands for the perovskite layer and the optimization of the charge-transport layer have great potential for the development of high-performance PeLEDs.
关键词： methylammonium lead bromide,hydrophilic polymer,conjugated ligand,surface-modified hole-transport layer,perovskite light-emitting diodes,4-aminobenzonitrile
更新于2025-09-23 15:19:57
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Perovskite Solar Cells: A Porous Graphitic Carbon based Hole Transporter/Counter Electrode Material Extracted from an Invasive Plant Species Eichhornia Crassipes
摘要： perovskite solar cells (pScs) composed of organic polymer-based hole-transporting materials (HtMs) are considered to be an important strategy in improving the device performance, to compete with conventional solar cells. Yet the use of such expensive and unstable HTMs, together with hygroscopic perovskite structure remains a concern – an arguable aspect for the prospect of onsite photovoltaic (PV) application. Herein, we have demonstrated the sustainable fabrication of efficient and air-stable PSCs composed of an invasive plant (Eichhornia crassipes) extracted porous graphitic carbon (ec-Gc) which plays a dual role as HTM/counter electrode. The changes in annealing temperature (~450 °C, ~850 °C and ~1000 °C) while extracting the EC-GC, made a significant impact on the degree of graphitization - a remarkable criterion in determining the device performance. Hence, the fabricated champion device-1c: Glass/fto/c-tio2/mp-tio2/cH3nH3pbi3?xclx/EC-GC10@CH3nH3pbi3?x clx/EC-GC10) exhibited a PCE of 8.52%. Surprisingly, the introduced EC-GC10 encapsulated perovskite interfacial layer at the perovskite/HtM interface helps in overcoming the moisture degradation of the hygroscopic perovskite layer in which the same champion device-1c evinced better air stability retaining its efficiency ~94.40% for 1000 hours. We believe that this present work on invasive plant extracted carbon playing a dual role, together as an interfacial layer may pave the way towards a reliable perovskite photovoltaic device at low-cost.
关键词： Eichhornia crassipes,hole-transporting materials,porous graphitic carbon,perovskite solar cells,device stability
更新于2025-09-23 15:19:57
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Effects of non-halogenated solvent on the main properties of a solution-processed polymeric thin film for photovoltaic applications: a computational study
摘要： Organic photovoltaic (OPV) devices reached high solar conversion efficiencies but they are usually processed using halogenated toxic solvents. Hence, before OPV devices can be mass-produced by industrial processing, it would be desirable to replace those solvents with eco-friendly ones. Theoretical tools may be then a powerful ally in the search for those new solvents. In order to better understand the mechanisms behind the interaction between solvent and polymer, classical molecular dynamics (MD) calculations was used to produce a thin film of poly(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl (PTB7-Th), processed using two different solvents. The PTB7-Th is widely applied as a donor material in OPVs. The first solvent is the ortho-dichlorobenzene (o-DCB), which is a highly toxic solvent widely used in lab-scale studies. The second solvent is the ortho-methylanisole (o-MA), which is an eco-friendly solvent for organic photovoltaic (OPV) manufacturing. Here we use a solvent evaporation protocol to simulate the formation of the PTB7-Th film. We demonstrate that our theoretical MD calculations were able to capture some differences in macroscopic properties of thin films formed by o-DCB or o-MA evaporation. We found that the interaction of the halogenated solvent with the polymer tends to break the bonds between the lateral thiophenediyl groups and the main chain. We show that those defects may create traps that can affect the charge transport and also can be responsible for a blue shift in the absorption spectrum. Using the Monte Carlo method, we also verified the influence of the resulting MD morphology on the mobility of holes. Our theoretical results showed a good agreement with the experimental measurements and both demonstrate that o-MA can be used to make polymer thin films without any loss of key properties for the device performance. The findings here highlights the importance of theoretical results as a guide to the morphological optimization of green processed polymeric films.
关键词： Solvent evaporation,PTB7-Th,Molecular dynamics,Organic photovoltaic,Halogenated solvents,Eco-friendly solvents,Hole mobility
更新于2025-09-23 15:19:57
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A Chemically Orthogonal Hole Transport Layer for Efficient Colloidal Quantum Dot Solar Cells
摘要： Colloidal quantum dots (CQDs) are of interest in light of their solution-processing and bandgap tuning. Advances in the performance of CQD optoelectronic devices require fine control over the properties of each layer in the device materials stack. This is particularly challenging in the present best CQD solar cells, since these employ a p-type hole-transport layer (HTL) implemented using 1,2-ethanedithiol (EDT) ligand exchange on top of the CQD active layer. It is established that the high reactivity of EDT causes a severe chemical modification to the active layer that deteriorates charge extraction. By combining elemental mapping with the spatial charge collection efficiency in CQD solar cells, the key materials interface dominating the subpar performance of prior CQD PV devices is demonstrated. This motivates to develop a chemically orthogonal HTL that consists of malonic-acid-crosslinked CQDs. The new crosslinking strategy preserves the surface chemistry of the active layer beneath, and at the same time provides the needed efficient charge extraction. The new HTL enables a 1.4× increase in charge carrier diffusion length in the active layer; and as a result leads to an improvement in power conversion efficiency to 13.0% compared to EDT standard cells (12.2%).
关键词： hole transport layers,colloidal quantum dots,solar cells,chemical orthogonality,surface ligands
更新于2025-09-23 15:19:57
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[Institution of Engineering and Technology 8th Renewable Power Generation Conference (RPG 2019) - Shanghai, China (24-25 Oct. 2019)] 8th Renewable Power Generation Conference (RPG 2019) - Power grid frequency regulation participated by photovoltaic generation to adapt to different control modes of grid-side AGC
摘要： Labeling connected components and calculating the Euler number in a binary image are two fundamental processes for computer vision and pattern recognition. This paper presents an ingenious method for identifying a hole in a binary image in the first scan of connected-component labeling. Our algorithm can perform connected component labeling and Euler number computing simultaneously, and it can also calculate the connected component (object) number and the hole number efficiently. The additional cost for calculating the hole number is only O(H), where H is the hole number in the image. Our algorithm can be implemented almost in the same way as a conventional equivalent-label-set-based connected-component labeling algorithm. We prove the correctness of our algorithm and use experimental results for various kinds of images to demonstrate the power of our algorithm.
关键词： image feature,the Euler number,image analysis,the hole number,pattern recognition,Computer vision
更新于2025-09-23 15:19:57
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Novel hole transporting material based on tetrathiafulvalene derivative: A step towards dopant free, ambient stable and efficient perovskite solar cells
摘要： Performance of hole transporting material (HTM) plays a fundamental role in estimating overall efficiency of perovskite solar cell (PSC). Dopant free HTMs with high intrinsic hole mobility and stability have been emerged as a fascinating choice for production of highly efficient and stable PSCs. Here, we report facile synthesis and implementation of a novel tetrathiafulvalene (TTF) derivative as a dopant free HTM for efficient and ambient stable PSC. The PSC based on dopant free TTF HTM shows remarkable photovoltaic efficiency of 15.66% which is one of highest value for any TTF based HTM. Beside efficiency, PSC based on TTF HTM shows only about 16% decline in initial efficiency even after 45 days storage in ambient conditions without any encapsulation which verifies its excellent ambient stability and hydrophobicity. Furthermore, various physical, electrochemical, photovoltaic and optical parameters of TTF HTM are investigated by highly specialized characterization tools. We affirm these results will be helpful for developing novel HTMs for highly efficient and stable PSCs in future.
关键词： Stability,Hole transporting material,Tetrathiafulvalene,Perovskite solar cell,Efficiency
更新于2025-09-23 15:19:57