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Understanding the Impact of Cu-In-Ga-S Nanoparticles Compactness on Holes Transfer of Perovskite Solar Cells
摘要： Although a compact holes-transport-layer (HTL) ?lm has always been deemed mandatory for perovskite solar cells (PSCs), the impact their compactness on the device performance has rarely been studied in detail. In this work, based on a device structure of FTO/CIGS/perovskite/PCBM/ZrAcac/Ag, that effect was systematically investigated with respect to device performance along with photo-physics characterization tools. Depending on spin-coating speed, the grain size and coverage ratio of those CIGS ?lms on FTO substrates can be tuned, and this can result in different hole transfer ef?ciencies at the anode interface. At a speed of 4000 r.p.m., the band level offset between the perovskite and CIGS modi?ed FTO was reduced to a minimum of 0.02 eV, leading to the best device performance, with conversion ef?ciency of 15.16% and open-circuit voltage of 1.04 V, along with the suppression of hysteresis. We believe that the balance of grain size and coverage ratio of CIGS interlayers can be tuned to an optimal point in the competition between carrier transport and recombination at the interface based on the proposed mechanism. This paper de?nitely deepens our understanding of the hole transfer mechanism at the interface of PSC devices, and facilitates future design of high-performance devices.
关键词： perovskite solar cells,compactness,Cu-In-Ga-S,hole transfer,holes transport layer,recombination
更新于2025-11-21 10:59:37
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Hole-Transporting Poly(dendrimer)s as Electron Donors for Low Donor Organic Solar Cells with Efficient Charge Transport
摘要： Recent work on bulk-heterojunction organic solar cells has shown that photoexcitation of the electron acceptor followed by photoinduced hole transfer can play a significant role in photocurrent generation. To establish a clear understanding of the role of the donor in the photoinduced hole transfer process, we have synthesized a series of triphenylamine-based hole-transporting poly(dendrimer)s with mechanically flexible nonconjugated backbones via ring-opening metathesis polymerization and used them in low donor content solar cells. The poly(dendrimer)s were found to retain the hole transporting properties of the parent dendrimer, with hole mobilities of ～10?3 cm2/(V s) for solution processed neat films. However, when blended with [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM), the best performing poly(dendrimer) was found to form films that had balanced and relatively high hole/electron mobilities of ～5 × 10?4 cm2/(V s). In contrast, at the same concentration the parent dendrimer:PC70BM blend was found to have a hole mobility of 4 orders of magnitude less than the electron mobility. The balanced hole and electron mobilities for the 6 wt % poly(dendrimer):PC70BM blend led to an absence of second-order bimolecular recombination losses at the maximum power point and resulted in a fill factor of 0.65 and a PCE 2.1% for the devices, which was almost three times higher than the cells composed of the parent dendrimer:PC70BM blends.
关键词： photoinduced hole transfer,charge transport,organic solar cells,hole-transporting poly(dendrimer)s,low donor content
更新于2025-09-23 15:19:57
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Higha??Performance Ternary Organic Solar Cells with Morphologya??Modulated Hole Transfer and Improved Ultraviolet Photostability
摘要： Ternary bulk-heterojunction (BHJ) strategy synergistically combining the merits of fullerene and non-fullerene acceptors has been regarded as a promising approach to enhance the power conversion efficiencies (PCEs) of organic solar cells (OSCs). Herein, the fullerene derivative ICBA as the morphology regulator is incorporated into non-fullerene based PBDB-T-2F:BTP-4Cl (PM6:BTP-4Cl) system to fabricate the high-performance ternary OSCs. The amorphous ICBA prefers to homogeneously distribute in the BTP-4Cl phase to form the well-mixed acceptor domains due to their better miscibility, which distinctly reduces the exciton decay loss driven by the unfavorable phase separation and enhances BHJ morphology stability of ternary blends. The appropriate addition of ICBA induces the efficient long-range F?rster resonance energy transfer to BTP-4Cl and facilitates the ultrafast hole transfer process from BTP-4Cl to PM6, thereby contributing to charge carrier generation in the actual devices. Ultimately, the optimal ternary OSCs not only yield the average PCE higher than 16.5% but also show the superior ultraviolet photostability relative to binary control devices owing to the increased harvesting of ultraviolet photons, boosted charge transfer, more balanced charge transport and more stable nano-structural morphology. Our results provide the new insights to enable the simultaneously improved device performance and tolerance to UV light in highly efficient ternary OSCs.
关键词： hole transfer,non-fullerene,ultraviolet photostability,ternary organic solar cells
更新于2025-09-23 15:19:57
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Hybrid Nanostructures of 2D CdSe Nanoplatelets for High-Performance Photodetector Using Charge Transfer Process
摘要： Two-dimensional (2D) semiconductor colloidal nanoplatelets (NPLs) have shown great potential as light-harvesting materials due to their advanced optical properties. Here, we have designed hybrid nanostructures of 2D CdSe nanoplatelets with phenothiazine (PTZ) for high-performance photodetector with varying thickness of CdSe NPLs by controlling charge transfer process. Significant photoluminescence quenching and the shortening of the average decay time of CdSe NPLs in presence of PTZ reveal the charge transfer process. Transient absorption (TA) spectroscopic analysis reveals the hot carrier cooling dynamics varies with changing the thickness of monolayers (ML) of CdSe NPLs. Furthermore, the slow exciton recombination of CdSe NPLs in presence of PTZ indicates the efficient charge separation. The optimized CdSe NPLs-PTZ hybrid exhibits a significant enhancement of photocurrent (~4.7×103 fold photo-to-dark current ratio) as compared to pure 3 ML CdSe NPLs (~10 fold) at the applied voltage of 1.5V. The measured external quantum efficiency, maximum detectivity and response time for the optimized hybrid are found to be ~40%, 4×1011 Jones and 107 milliseconds, with the responsivity value of 160 mA/W. These highly efficient measured parameters clearly suggest that CdSe NPLs-PTZ hybrid systems are promising alternate for ultrasensitive photodetector.
关键词： 2D colloidal nanoplatelets,photodetectors,hole transfer,hybrids,photocurrent
更新于2025-09-23 15:19:57
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Role of Regeneration of Nanoclusters in Dictating the Power Conversion Efficiency of Metal-Nanocluster-Sensitized Solar Cells
摘要： Metal nanoclusters (NCs) have emerged as feasible alternatives to dyes and quantum dots in light energy conversion applications. Despite the remarkable enhancement in power conversion efficiency (PCE) in recent years and the increase in the number of NCs available as sensitizers, a comprehensive understanding of the various interfacial charge-transfer, transport, and recombination events in NCs is still lacking. This understanding is vital to the establishment of design principles for an efficient photoelectrode that uses NCs. In this work, we carefully design a comparison study of two representative NCs, Au and Ag, based on transient absorption spectroscopy and electrochemical impedance spectroscopy, methods that shed light on the true benefits and limitations of NC sensitizers. Low NC regeneration efficiency is the most critical factor that limits the performance of metal-nanocluster-sensitized solar cells (MCSSCs). The slow regeneration that results from sluggish hole transfer kinetics not only limits photocurrent generation efficiency but also has a profound effect on the stability of MCSSCs. This finding calls for urgent attention to the development of an efficient redox couple that has a great hole extraction ability and no corrosive nature. This work also reveals different interfacial behaviors of Au and Ag NCs in photoelectrodes, suggesting that utilizing the benefits of both types of NCs simultaneously by co-sensitization or using AuAg alloy NCs may be one avenue to further PCE improvement in MCSSCs.
关键词： metal nanoclusters,regeneration,light energy conversion,solar cells,hole transfer
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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Selfa??Crystallized Multifunctional 2D Perovskite for Efficient and Stable Perovskite Solar Cells
摘要： Recently, perovskite solar cells (PSC) with high power-conversion efficiency (PCE) and long-term stability have been achieved by employing 2D perovskite layers on 3D perovskite light absorbers. However, in-depth studies on the material and the interface between the two perovskite layers are still required to understand the role of the 2D perovskite in PSCs. Self-crystallization of 2D perovskite is successfully induced by deposition of benzyl ammonium iodide (BnAI) on top of a 3D perovskite light absorber. The self-crystallized 2D perovskite can perform a multifunctional role in facilitating hole transfer, owing to its random crystalline orientation and passivating traps in the 3D perovskite. The use of the multifunctional 2D perovskite (M2P) leads to improvement in PCE and long-term stability of PSCs both with and without organic hole transporting material (HTM), 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (spiro-OMeTAD) compared to the devices without the M2P.
关键词： trap passivation,hole-transporting layers,hole-transfer facilitators,2D perovskites,perovskite solar cells
更新于2025-09-19 17:13:59
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Hole Transfer Promoted by a Viscosity Additive in an All-Polymer Photovoltaic Blend
摘要： Viscosity modi?ers are widely applied to improve the mechanical compliance of organic optoelectronic devices. However, the e?ect of the viscosity additives on the charge dynamics remains poorly understood. Here, we report the observation of markedly di?erent e?ects of a high-viscosity polymeric additive on the electron- and hole-transfer dynamics in all-polymer organic photovoltaic blends. By using ultrafast transient absorption spectroscopy, we determine that hole transfer from charge-transfer excitations in the acceptor is markedly promoted while the electron transfer from local excitations in the donor remains nearly unchanged upon introduction of viscosity additives into the blends. We argue that the modi?cation of dielectric screening is the mechanism underlying the e?ect of the additive on the charge dynamics. This ?nding suggests a new strategy for designing high-performance ?exible organic photovoltaic devices by manipulating the dielectric environment.
关键词： electron transfer,hole transfer,viscosity additives,dielectric screening,all-polymer photovoltaic blends
更新于2025-09-19 17:13:59
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Ultrafast Hole Transfer and Carrier Transport Controlled by Nanoscale-Phase Morphology in Nonfullerene Organic Solar Cells
摘要： Nonfullerene acceptors (NFAs) have attracted great attention in high-efficiency organic solar cells (OSCs). While the effect of molecular properties including structures and energetics on charge transfer have been extensively investigated, the effect of macroscopic phase properties is yet to be revealed. Here we have performed a correlation study of the nanoscale phase morphology on photoexcited hole transfer (HT) process and photovoltaic performance, by combing ultrafast spectroscopy with high temporal resolution and photo-induced force microscopy (PiFM) with high spatial and chemical resolution. In PM6/IT-4F, we observe a biphasic HT behavior with a minor ultrafast (< 100 fs) interfacial process and a major diffusion mediated HT process till ~ 100 ps, which depends on phase segregation strongly. Because of the interplay between charge transfer and transport, a compromised domain size of 20 ~ 30 nm for NFAs shows best performance. This study highlights the critical role of phase morphology in high-efficiency OSCs.
关键词： photo-induced force microscopy,phase morphology,ultrafast spectroscopy,organic solar cells,hole transfer,Nonfullerene acceptors
更新于2025-09-19 17:13:59
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Hole-transporting materials for low donor content organic solar cells: Charge transport and device performance
摘要： Low donor content solar cells are an intriguing class of photovoltaic device about which there is still considerable discussion with respect to their mode of operation. We have synthesized a series of triphenylamine-based materials for use in low donor content devices with the electron accepting [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). The triphenylamine-based materials absorb light in the near UV enabling the PC71BM to be essentially the light absorbing organic semiconducting material in the solar cell. It was found that the devices did not operate as classical Schottky junctions but rather photocurrent was generated by hole transfer from the photoexcited PC71BM to the triphenylamine-based donors. We found that replacing the methoxy surface groups with methyl groups on the donor material led to a decrease in hole mobility for the neat films, which was due to the methyl substituted materials having the propensity to aggregate. The thermodynamic drive to aggregate was advantageous for the performance of the low donor content (6 wt%) films. It was found that the 6 wt% donor devices generally gave higher performance than devices containing 50 wt% of the donor.
关键词： hole mobility,low donor content,photoexcited hole transfer,Schottky junction,synthesis,photocurrent generation
更新于2025-09-16 10:30:52