Publications by authors named "Yuliar Firdaus"

In response to escalating global concerns over environmental pollution, the development of green dye-sensitized solar cells (DSSCs) has emerged as a promising technology for solar energy conversion. This study harnesses the potential of rice husk, an abundant agricultural waste in Indonesia, by extracting lignin through a simple recycling method. Lignin acts as a natural, non-toxic dopant and template for TiO₂ composites, enhancing the stability of the photoanode in DSSCs.

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The significant contact resistance at the metal-semiconductor interface is a well-documented issue for organic thin-film transistors (OTFTs) that hinders device and circuit performance. Here, this issue is tackled by developing three new thiol carbazole-based self-assembled monolayer (SAM) molecules, namely tBu-2SCz, 2SCz, and Br-2SCz, and utilizing them as carrier-selective injection interlayers. The SAMs alter the work function of gold electrodes by more than 1 eV, making them suitable for use in hole and electron-transporting OTFTs.

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Bisthienoazepinedione (BTA) has been reported for constructing high-performing p-type conjugated polymers in organic electronics, but the ring extended version of BTA is not well explored. In this work, we report a new synthesis of a key building block to the ring expanded electron-deficient pentacyclic azepinedione (BTTA). Three copolymers of BTAA with benzodithiophene substituted by different side chains are prepared.

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Copper thiocyanate (CuSCN) is a p-type semiconductor that exhibits hole-transport and wide-band gap (∼3.9 eV) characteristics. However, the conductivity of CuSCN is not sufficiently high, which limits its potential application in optoelectronic devices.

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Electronic doping in organic materials has remained an elusive concept for several decades. It drew considerable attention in the early days in the quest for organic materials with high electrical conductivity, paving the way for the pioneering work on pristine organic semiconductors (OSCs) and their eventual use in a plethora of applications. Despite this early trend, however, recent strides in the field of organic electronics have been made hand in hand with the development and use of dopants to the point that are now ubiquitous.

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Hybrid devices based on a heterojunction between inorganic and organic semiconductors have offered a means to combine the advantages of both classes of materials in optoelectronic devices, but, in practice, the performance of such devices has often been disappointing. Here, it is demonstrated that charge generation in hybrid inorganic-organic heterojunctions consisting of copper thiocyanate (CuSCN) and a variety of molecular acceptors (ITIC, IT-4F, Y6, PC BM, C , C ) proceeds via emissive charge-transfer (CT) states analogous to those found at all-organic heterojunctions. Importantly, contrary to what has been observed at previous organic-inorganic heterojunctions, the dissociation of the CT-exciton and subsequent charge separation is efficient, allowing the fabrication of planar photovoltaic devices with very low non-radiative voltage losses (0.

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Self-assembled monolayers (SAMs) based on Br-2PACz ([2-(3,6-dibromo-9H-carbazol-9-yl)ethyl]phosphonic acid) 2PACz ([2-(9H-Carbazol-9-yl)ethyl]phosphonic acid) and MeO-2PACz ([2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid) molecules were investigated as hole-extracting interlayers in organic photovoltaics (OPVs). The highest occupied molecular orbital (HOMO) energies of these SAMs were measured at -6.01 and -5.

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In bulk heterojunction (BHJ) organic solar cells (OSCs) both the electron affinity (EA) and ionization energy (IE) offsets at the donor-acceptor interface should equally control exciton dissociation. Here, we demonstrate that in low-bandgap non-fullerene acceptor (NFA) BHJs ultrafast donor-to-acceptor energy transfer precedes hole transfer from the acceptor to the donor and thus renders the EA offset virtually unimportant. Moreover, sizeable bulk IE offsets of about 0.

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The short exciton diffusion length associated with most classical organic semiconductors used in organic photovoltaics (5-20 nm) imposes severe limits on the maximum size of the donor and acceptor domains within the photoactive layer of the cell. Identifying materials that are able to transport excitons over longer distances can help advancing our understanding and lead to solar cells with higher efficiency. Here, we measure the exciton diffusion length in a wide range of nonfullerene acceptor molecules using two different experimental techniques based on photocurrent and ultrafast spectroscopy measurements.

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Polydopamine has been widely used as an additive to enhance membrane fouling resistance. This study reports the effects of two-step dopamine-to-polydopamine modification on the permeation, antifouling, and potential anti-UV properties of polyethersulfone (PES)-based ultrafiltration membranes. The modification was performed through a two-step mechanism: adding the dopamine additive followed by immersion into Tris-HCl solution to allow polymerization of dopamine into polydopamine (PDA).

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Recent advances in solution-processable semiconducting colloidal quantum dots (CQDs) have enabled their use in a range of (opto)electronic devices. In most of these studies, device fabrication relied almost exclusively on thermal annealing to remove organic residues and enhance inter-CQD electronic coupling. Despite its widespread use, however, thermal annealing is a lengthy process, while its effectiveness to eliminate organic residues remains limited.

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Molecular doping is often used in organic semiconductors to tune their (opto)electronic properties. Despite its versatility, however, its application in organic photovoltaics (OPVs) remains limited and restricted to p-type dopants. In an effort to control the charge transport within the bulk-heterojunction (BHJ) of OPVs, the n-type dopant benzyl viologen (BV) is incorporated in a BHJ composed of the donor polymer PM6 and the small-molecule acceptor IT-4F.

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Benefiting from their extraordinary physical properties, methylammonium lead halide perovskites (PVKs) have attracted significant attention in optoelectronics. However, the PVK-based devices suffer from low carrier mobility and high operation voltage. Here, we utilize sorted semiconducting single-walled carbon nanotubes (95% s-SWCNTs) to enhance the performance of thin-film transistors (TFTs) based on the mixed-cation perovskite (MAFA)Pb(IBr), enabling mixed-dimensional solution-processed electronics with high mobility (32.

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The application of liquid-exfoliated 2D transition metal disulfides (TMDs) as the hole transport layers (HTLs) in nonfullerene-based organic solar cells is reported. It is shown that solution processing of few-layer WS or MoS suspensions directly onto transparent indium tin oxide (ITO) electrodes changes their work function without the need for any further treatment. HTLs comprising WS are found to exhibit higher uniformity on ITO than those of MoS and consistently yield solar cells with superior power conversion efficiency (PCE), improved fill factor (FF), enhanced short-circuit current (J ), and lower series resistance than devices based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and MoS .

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The reported power conversion efficiencies (PCEs) of nonfullerene acceptor (NFA) based organic photovoltaics (OPVs) now exceed 14% and 17% for single-junction and two-terminal tandem cells, respectively. However, increasing the PCE further requires an improved understanding of the factors limiting the device efficiency. Here, the efficiency limits of single-junction and two-terminal tandem NFA-based OPV cells are examined with the aid of a numerical device simulator that takes into account the optical properties of the active material(s), charge recombination effects, and the hole and electron mobilities in the active layer of the device.

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Article Synopsis
  • * A new type of solar cell using these fullerenes alone as light-absorbing materials shows promising results, achieving a power conversion efficiency (PCE) of around 1% initially, which increases to 5.4% when blended with a p-type semiconductor, copper (I) thiocyanate (CuSCN).
  • * The study highlights the formation of a unique p-n-like heterointerface between CuSCN and the fullerene derivatives as a critical factor for improving solar cell performance, suggesting possibilities for innovative solar technologies.
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Poly(isoindigo-alt-3,4-difluorothiophene) (PIID[2F]T) analogues used as "polymer acceptors" in bulk-heterojunction (BHJ) solar cells achieve >7 % efficiency when used in conjunction with the polymer donor PBFTAZ (model system; copolymer of benzo[1,2-b:4,5-b']dithiophene and 5,6-difluorobenzotriazole). Considering that most efficient polymer-acceptor alternatives to fullerenes (e.g.

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Monolithically integrated hybrid tandem solar cells that effectively combine solution-processed colloidal quantum dot (CQD) and organic bulk heterojunction subcells to achieve tandem performance that surpasses the individual subcell efficiencies have not been demonstrated to date. In this work, we demonstrate hybrid tandem cells with a low bandgap PbS CQD subcell harvesting the visible and near-infrared photons and a polymer:fullerene-poly (diketopyrrolopyrrole-terthiophene) (PDPP3T):[6,6]-phenyl-C-butyric acid methyl ester (PCBM)-top cell absorbing effectively the red and near-infrared photons of the solar spectrum in a complementary fashion. The two subcells are connected in series via an interconnecting layer (ICL) composed of a metal oxide layer, a conjugated polyelectrolyte, and an ultrathin layer of Au.

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A novel π-conjugated triad and a polymer incorporating indolo[3,2-b]-carbazole (ICZ) and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) were synthesized via a Sonogashira coupling. Compared to the parent BODIPY the absorption and fluorescence spectrum were for both compounds broader and redshifted. The redshift of the fluorescence and the decrease of the fluorescence quantum yield and decay time upon increasing solvent polarity were attributed to the formation of a partial charge-transfer state.

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