Maximum Conversion Research Articles

Nanostructured bismuth chloride based ((CH3NH3)3Bi2IxCl9-x) active layers for lead-free perovskite solar cells

Abstract Bismuth is one of the promising elements that can replace toxic lead in perovskite solar cells. However, surface roughness and inhomogeneous morphology with voids on the bismuth perovskite films limits their photovoltaic performance. In the present work, a scalable doctor-blade technique is employed to prepare perovskite thin film with high surface coverage. Methylammonium bismuth halide (MABiH) ((CH3NH3)3Bi2ClxI9-x) nanoparticles were synthesized by conventional sol-gel technique. The formation of perovskite structure was confirmed by X-ray diffraction measurement which confirmed that MABiH perovskite films were in hexagonal symmetry with polycrystalline nature. The prepared perovskite nanoparticles were deposited on mesoporous TiO2-coated FTO substrates through the spin coating technique and doctor blade method. Morphology analysis of MABiH perovskite revealed the formation of an orange Lily-like structure with higher surface coverage. Lead-free mesoporous perovskite solar cells prepared using MABiH perovskite material with carbon as hole extraction layer showed a maximum power conversion efficiency (PCE) of 0.004 %, with short circuit current density of 89 μA/cm2, open circuit voltage of 0.12 V and fill factor of 38 %. These results allow us to step toward fabricating bulk MABiH lead-free perovskite solar cells.

Design and simulation of CsPb.625Zn.375IBr2-based perovskite solar cells with different charge transport layers for efficiency enhancement

In this work, CsPb.625Zn.375IBr2-based perovskite solar cells (PSCs) are numerically simulated and optimized under ideal lighting conditions using the SCAPS-1D simulator. We investigate how various hole transport layers (HTL) including Zn3P2, PTAA, MoS2, MoO3, MEH-PPV, GaAs, CuAlO2, Cu2Te, ZnTe, MoTe2, CMTS, CNTS, CZTS, CZTSe and electron transport layers (ETL) such as CdS, SnS2, ZnSe, PC60BM interact with the devices’ functionality. Following HTL material optimization, a maximum power conversion efficiency (PCE) of 16.59% was observed for the FTO/SnS2/CsPb.625Zn.375IBr2/MoS2/Au structure, with MoS2 proving to be a more economical option. The remainder of the investigation is done following the HTL optimization. We study how the performance of the PSC is affected by varying the materials of the ETL and to improve the PCE of the device, we finally optimized the thickness, charge carrier densities, and defect densities of the absorber, ETL, and HTL. In the end, the optimized arrangement produced a VOC of 0.583 V, a JSC of 43.95 mA/cm2, an FF of 82.17%, and a PCE of 21.05% for the FTO/ZnSe/CsPb.625Zn.375IBr2/MoS2/Au structure. We also examine the effects of temperature, shunt resistance, series resistance, generation rate, recombination rate, current-voltage (JV) curve, and quantum efficiency (QE) properties to learn more about the performance of the optimized device. At 300 K, the optimized device provides the highest thermal stability. Our research shows the promise of CsPb.625Zn.375IBr2-based PSCs and offers insightful information for further development and improvement.

Solvent-free synthesis of citronellyl acetate using Fermase: Optimization, kinetics and RSM studies

Citronellyl acetate is a flavor ester with a fresh fruit aroma and a fruity, sweet flavor. The current study illustrates the synthesis of citronellyl acetate via a transesterification reaction of citronellol and vinyl acetate in a solvent-free system with the help of biocatalyst Fermase. The effect of various parameters affecting the reaction, including reactant mole ratio, enzyme loading, temperature, and agitation speed, was studied to obtain the maximum conversion of citronellol. Under optimized conditions with a 1:10 mole ratio of citronellol to vinyl acetate, 3% (w/w) enzyme loading with respect to citronellol, 300 RPM agitation speed, and 60 °C temperature, a maximum conversion of 99.8% was achieved in 2 h reaction time. The enzyme was reused for six reaction cycles, retaining 85% of its activity. Various kinetic models for enzymatic reactions were explored and validated. The ping-pong bi-bi model with both substrate inhibition gave the best fit for the experimental data. Optimization studies were also conducted using the response surface methodology to observe the interaction of various parameters.

A theoretical study on the insights of designing and optimization of a CsSn(IxBr1-x)3 based solar cell

This work focuses on designing and optimizing a lead-free perovskite solar cell. The significance of band gap grading in obtaining better performance of the solar cell was studied in detail with CsSn(IxBr1-x)3 () being used as the active absorber material. The device showed a maximum power conversion efficiency (PCE) of when the interfacial defects were not considered. The optimum thickness was obtained to be 1 μm, and the corresponding doping concentration was 1020 cm-3. Further, a detailed discussion on the band diagrams, electric fields, and different recombination processes has been carried out in this work to get an idea about the varying PCE values at different operating conditions. The presence of Shockley-Read-Hall (SRH) recombination at various temperature values was observed, which partially contributed to the reduction in PCE values at higher temperatures. This work also discusses briefly about the probable losses involved with the device, which may be considered as the plausible reasons for obtaining PCE values less than the SQ limit. This information opens up a wide window for researchers to experimentally fabricate solar cells with proper cautions so that a device with PCE value exceeding Shockley Quisser (SQ) limit can be made available commercially.

Hydrodynamic and reaction kinetic responses of CaO/CaCO3 carbonation in bubbling fluidized bed reactors for thermochemical energy storage: Influence of CO2 mole fraction, grain size, and reactor dimensions

The CaO/CaCO3 thermochemical energy storage system offers a promising method for the efficient utilization of solar energy. However, the reactor design remains underdeveloped. In this study, the Eulerian-Eulerian two-fluid model is employed to systematically investigate the effects of CO2 mole fraction, particle size, and reactor dimensions on the carbonation process in a bubbling fluidized bed reactor. Increasing the CO2 mole fraction from 50 % to 80 % reduces the duration of the chemical-reaction-kinetics controlled stage from 118.5 s to 65.3 s, and the transition stage from 64.6 s to 36.7 s, with minimal impact on the final conversion rate. High CO2 concentrations cause insufficient bed fluidization and uneven local conversion rate distribution within the bed. As the grain size increases from 150 nm to 300 nm and 600 nm, the duration of the chemical-reaction-kinetics controlled stage decreases from 118.5 s to 104.0 s and 76.2 s, respectively. This causes the reaction to enter the transition phase earlier, ultimately leading to a reduction in the maximum conversion rate. Altering the height and width of the reactor does not significantly impact the conversion processes within the reactor. These findings provide valuable insights for the optimization and practical industrial application of efficient reactors.

Grain Boundary Engineering Enhances the Thermoelectric Properties of Y2Te3

AbstractThe performance of thermoelectric materials is typically assessed using the dimensionless figure of merit, zT. Increasing zT is challenging due to the intricate relationships between electrical and thermal transport properties. This study focuses on Y2Te3‐based thermoelectric materials, which are predicted to be promising for high‐temperature applications due to their inherently low lattice thermal conductivity. A series of Y2+xTe3 compositions with excess Y is synthesized to explore the effects on electronic and structural characteristics. Density functional theory calculations suggest that additional Y atoms increase charge carriers, thereby enhancing electrical conductivity and boosting thermoelectric performance. X‐ray diffraction analysis reveals that the presence of excess Y reduces lattice volume and alters bonding structures. Furthermore, the addition of Bi significantly enhances the power factor by promoting the segregation of elemental Bi particles and the formation of Y‐Bi‐rich grain boundaries, which improve weighted mobility. This microstructural optimization leads to a fourfold increase in the Seebeck coefficient, resulting in a peak zT of 1.23 at 973 K and a predicted maximum conversion efficiency of 10.3% under a temperature difference of 673 K. These findings highlight the potential of Y2Te3 for high‐temperature thermoelectric applications and demonstrate the effectiveness of grain boundary engineering in enhancing thermoelectric performance.

Simultaneously comparing various CO2-mineralized steelmaking slags as supplementary cementitious materials via high gravity carbonation

The integration of accelerated carbonation with the utilization of steelmaking slags presents a vital strategy for CO2 mineralization towards net-zero scheme. This study simultaneously evaluates basic oxygen furnace slag (BOFS), refining slag (RFS), and electric arc furnace reducing (EAFRS) and oxidizing slags (EAFOS) as potential partial replacements for ordinary Portland cement, at substitution levels ranging from 5 % to 15 % as supplementary cementitious materials (SCMs). These slags were pretreated through aqueous accelerated carbonation in a high-gravity rotating packed bed. We assessed several parameters, including carbonation conversion, CO2 capture capacity, workability, strength, and durability. The results demonstrated that EAFRS achieved the highest CO2 capture capacity, reaching 0.193 kg-CO2/kg-slag with a maximum carbonation conversion of 46 % under 197 times high-gravity conditions and a liquid-to-solid ratio of 20. While the incorporation of carbonated slags had minimal impact on the setting properties of cement pastes, higher substitution ratios necessitated increased water demand. The strength of blended cement containing 5 %, 10 %, and 15 % of carbonated BOFS, RFS, and EAFRS met standard requirements at 28th day. Additionally, a mathematical model was developed to predict the mechanical strength of cement mortars. The introduction of carbonated BOFS, RFS, and EAFRS facilitated hydration due to the formation of calcium carbonates, although it resulted in slower strength development kinetics. Notably, the replacement of cement with carbonated EAFOS exhibited a higher expansion rate, likely due to its elevated silicon dioxide and alkaline species content, which may lead to alkali-aggregate reactions, resulting in expansion and cracking.

Potential Probiotic Bacillus Strains with Antioxidant and Antimutagenic Activity Increased Weight Gain and Altered hsp70, cxc, tnfα, il1β, and lysC Gene Expression in Clarias gariepinus

The potential probiotic properties of three Bacillus strains were studied. A probiotic supplement for the African catfish Clarias gariepinus was produced via the solid-state fermentation protocol and incorporated into the fish feed for a period of seven weeks. Since the 36th day of the experiment, all experimental groups had a statistically significant increase in their weight gain than the control group. The maximum weight gain observed in fish fed the probiotic-supplemented feed was 29.16% higher than that of the control group, and the maximum feed conversion rate improvement was 24%. Cell-free extracts from these strains showed antioxidant (11.55–27.40%) and DNA-protective (45.33–61.83%) activity in a series of in vitro biosensor tests. Further investigation into the antimutagenic activity of the strains revealed that two of them reduced the level of induced mutagenesis in an Escherichia coli model (by 33.58% and 54.35%, respectively). We also assessed the impact of probiotic strains on the expression of several key genes in the host (C. gariepinus), including hsp70, cxc, tnfα, il1β, and lysC. More than a 10-fold increase in expression rates was observed for hsp70 in gonads and liver; for cxc in muscles and gonads; for tnfα in brain, gills, and liver; for il1β in the brain, gills, gonads, and liver; and for lysC in gills, gonads, liver, and muscles. This study provides evidence that probiotics exhibiting antioxidant and antimutagenic properties can provide significant benefits in vivo within aquaculture systems. The molecular effects of these probiotics appear to be complex and tissue-specific, with both upregulation and downregulation of immune system genes observed. Nevertheless, at the organismal level, the impact was unequivocally positive in terms of aquaculture objectives, manifested as enhanced body weight gain in the fish. Consequently, these Bacillus strains warrant serious consideration as potential probiotics for this species.

Calcination Temperature Impacting the Structure and Activity of CuAl Catalyst in Aqueous Glycerol Hydrogenolysis to 1,2-Propanediol

AbstractThis study investigated the impact of calcination temperature on the structural properties of CuAl catalyst which was found to be a robust nano-structured catalyst calcined directly without ramping at 400 °C and performed exceedingly well for aqueous phase hydrogenolysis of glycerol. Various samples of CuAl catalysts were prepared by co-precipitation at Cu: Al molar ratio 1:1 and were calcined at different temperatures (300–1000 °C). The obtained catalysts were reduced at 200 °C before their activity testing for glycerol hydrogenolysis reaction. To correlate the structure-activity, the catalysts were thoroughly characterized by XRD, XPS, BET, TEM, H2-TPR, NH3-TPD, and pyridine FTIR. It was observed that with an increase in calcination temperature from 300 to 700 °C, the glycerol conversion also increased from 47 to 55% with 93% selectivity to 1,2-PDO. The better performance of these catalysts was mainly related to the predominant presence of Brønsted acid sites, an appropriate ratio of the Cu0 to CuAl2O4 + CuO (0.33) and CuAl2O4 to CuO phases (0.35), the existence of Cu2O phase and the smaller Cu0 particle size. It was shown that altering the ramping rate for the calcination temperature of 400 °C impacted the catalytic activity. The CuAl-400 (DC) (direct calcined) catalyst exhibited a maximum glycerol conversion of 60%.

A novel high-speed homogenizer assisted process intensification technique for biodiesel production using soya acid oil: Process optimization, kinetic and thermodynamic modelling

Acid oils, which are readily available and cost-effective, show promise as a feedstock for biodiesel synthesis. This study focuses on biodiesel production using soya acid oil having high free fatty acids (FFAs) content of 80.65 %. Biodiesel is produced from high-FFA soya acid oil by employing a novel high speed homogenizer technique through esterification process followed by neutralization step. The process variables affecting esterification reaction have been optimized through response surface methodology (RSM) based Box-Behnken Design (BBD) technique. A maximum FFA conversion of 98.06 % was found at a M:O molar proportion of 18.41:1, a process time of 84.62 min, a catalyst amount of 2.18 wt%, and a rotational speed of 14,100 RPM. The determined activation energy for esterification reaction using high speed homogenizer was 36.82 kJ/mol, which is 1.5 to 2 times lower compared to conventional techniques. Thermodynamic behaviour of esterification reaction was studied and analysed. The resulting biodiesel after the neutralization step meets the EN 14214 standard for conversion rate (minimum 96.5 %) and physicochemical properties, ensuring commercial viability.

The decomposition of Fe-substituted rhodochrosite during coaling enhanced the transformation of NO before catalyst bed: Effect of instant-calcination

The NO conversion by Fe-substituted rhodochrosite before flue gas treatment systems in coaling plants needs further investigation. Hence the effect of Fe substitution on the conversion of rhodochrosite during coal combustion process conditions and the denitration efficiency of transformed products after NH3 injection were investigated. To simulate the reality of coaling process, Fe-substituted manganese oxide was obtained by instant heat treatment of Fe-substituted rhodochrosite. The manganese oxide obtained from the instant-calcined rhodochrosite had promising catalytic activity, the substitution of Fe slightly enhanced NO conversion efficiency at 100–200 ºC and 3 %Fe-850 exhibited the maximum NO conversion of 99.6 % at 150 ºC. Besides, the Fe doping enabled the thermal decomposition product of rhodochrosite to have higher porosity, lager surface area, more chemisorbed oxygen and acid sites, better redox capacity and greater relative content of Mn4+. Furthermore, in-situ DRIFTs experiment demonstrated Fe doping increased the number of acid site and promoted the formation of intermediates (-NH2) and monodentate nitrite, which will benefit catalytic activity. Moreover, E-R mechanism was dominant in the reaction at different temperatures. This work improves our understanding of the de-NOx behavior following NH3 injection during coaling.

Non-Hermitian selective thermal emitter for thermophotovoltaics

For a sustainable future, efficient, compact, and solid-state energy converters are critical. Thermophotovoltaics (TPV)—a solid-state scheme to convert heat into electricity—is promising for thermal storage and generation1. TPV systems employing selective thermal emitters allow compact designs for various terrestrial and space applications and, hence, have garnered much attention. Despite significant research efforts, these systems have low efficiency. The selective thermal emitter and the low-bandgap photovoltaic cell contribute to this problem. Here, we solve the shortcomings of the thermal emitter by using a novel approach inspired by non-Hermitian optics. We demonstrate a hybrid metal-dielectric non-Hermitian selective emitter (NHE) with high spectral efficiency (> 60%) and employ the NHE in a TPV system operating at 1273 K. We show that a maximum TPV conversion efficiency of 12% is possible at 1273 K, though our preliminary experiments employing an uncooled PV cell showed a much lower efficiency.

Itaconic acid/cellulose-based hydrogels with fire-resistant and anti-freezing properties via vat photopolymerization 3D printing

Hydrogel-born materials have garnered significant interest due to their inherent flame retardant properties and eco-friendly characteristics. In light of the diminishing petroleum reserves and the escalating environmental challenges, there is an urgent impetus to exploit high-value applications of naturally occurring resources and to advance research in sustainable manufacturing technologies. In this vein, we describe an innovative and sustainable methodology for the development and production of flame-retardant hydrogels. This approach perfectly integrates renewable itaconic acid and cellulose derivatives with rapid vat photopolymerization (VP) 3D printing technology, which affords a green and efficient route for materials processing. Specifically, the biomass-based ink formulated for 3D printing demonstrates excellent visible-light curing properties, achieving a maximum double-bond conversion of 45.3 % within 10 min of exposure to visible-light LED under ambient conditions. Moreover, the resultant 3D-printed biomass-based hydrogels exhibit commendable flame-retardant performance, as evidenced by a V-0 flammability rating and a Limiting Oxygen Index (LOI) value of 60.2 %. They also possess desirable mechanical attributes (95.2 kPa) and exceptional thermal stability, enduring high temperatures for up to 12 min. Notably, these hydrogels exhibit remarkable freeze tolerance, maintaining their functionality even at profoundly low temperatures. This study demonstrates a novel strategy for the design and production of flame-retardant materials, contributing to the pursuit of green sustainability.

A Q‐Learning and Fuzzy Logic Control of Hybrid Energy Storage System Using Two Stage Low‐Pass Filter to Smooth Power Fluctuations in Microgrid

ABSTRACTThe intermittent and fluctuating nature of wind turbine output power is increasingly being recognized as a significant issue adversely impacting the power quality and stability of electrical grids. With the increasing integration of wind power, this challenge cannot be underestimated. However, a potential solution for mitigating the adverse effects of such fluctuations lies in the Hybrid Energy Storage System (HESS), which encompasses battery energy storage systems (BESS) and supercapacitors (SC). The HESS is equipped with flexible operational modes for charging and discharging, thus enabling grid‐connected microgrids to possess the ability to counteract these oscillations. In this article, a control strategy based on the combination of Q‐learning and fuzzy logic control approaches is presented for tuning the parameters of a utilized two‐stage variable time constant low‐pass filter (LPF) in a grid‐connected microgrid. The proposed strategy adaptively tunes the time constants of LPFs to mitigate wind power fluctuations. Furthermore, practical constraints for the energy storage systems and their interfaced converters, such as preventing overcharge/discharge, ramp rate requirements, and certain maximum power conversion ranges, have been taken into account. Numerical simulation results verify the effectiveness of the proposed two‐stage variable time constant LPF for output wind power fluctuation reduction considering practical constraints of HESS.

Synergistic Effects in MoS2/Co3O4/Cu2O Nanocomposites for Superior Solar Cell and Photodegradation Efficiency

Herein, we synthesized a Cu2O and Co3O4 incorporation with MoS2 to produce MoS2/Co3O4/Cu2O nanocomposites by facile sonication assisted hydrothermal methods. The phase structure and elemental composition of MoS2/Co3O4/Cu2O nanocomposites were investigated using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) morphology studies confirm that MoS2/Co3O4 nanostructure self-assembles in a mixed nanosheet configuration after the introduction of Cu2O. The synthesized samples were used as new types of Pt-free counter electrodes (CE) for DSSCs. Among all, the DSSCs based on the MoS2/Co3O4/Cu2O CE yields a maximum power conversion efficiency of 3.68% (Jsc = 8.2mAcm-2, Voc = 0.71mV and FF = 0.629%) under the standard AM 1.5G illumination, which is 2.5 times higher than that of pure MoS2. To assess the photocatalytic activity, prepared samples were used to suppress methylene blue (MB) and rhodamine B (RhB) dye under UV-visible light irradiation. The MoS2/Co3O4/Cu2O nanocomposites had the highest photocatalytic degradation efficiency of all the samples. It increased degradation efficiency from 43% to 91% for MB dye after 100minutes, and from 47% to 92% for RhB dye after 90minutes. Scavengers test analysis proved that the superoxide radical (•O2-) play a major role in the MoS2/Co3O4/Cu2O photocatalytic system. After four consecutive photocatalytic cycles, the crystal structure and surface morphology of the MoS2/Co3O4/Cu2O nanocomposites used in the 4th cycle were more stable, and this was confirmed by SEM, EDAX and XRD studies. The broader significance of these findings provides a straightforward approach for synthesizing a low-cost and high-efficiency MoS2/Co3O4/Cu2O nanocomposite for CE in DSSC photovoltaic cells and facilitates organic pollutant removal through photocatalytic applications.

Homogeneous catalytic oxidation of thymol with dinuclear Cu(II)-2-phenyl propionate-bipyridine complex

A carboxylate-bridged dinuclear copper(II) complex, [Cu2(μ2-η2:η1(ppa)2(μ2-η1:η1 (ppa)bpy)2]·ClO4·H2O (ppa (C9H9OO) = 2-phenyl propionate, bpy = 2,2′-bipyridine), was prepared and its structure was determined by X-ray diffraction analysis. The octacoordinated Cu(II) dimer complex exhibits an asymmetric conformation, with the metal centers linked by two distinct modes of the carboxylate group. These include an asymmetric chelating bridging bidentate involving two ppa ligands and a syn-syn bidentate bridging mode involving one ppa ligand. The complex was employed as a catalyst for the oxidation of thymol, demonstrating a high degree of quantitative conversion and selectivity with TBHP across a range of solvents at moderate temperatures. The homogeneous catalytic system, comprising Cu(II)-2-phenyl propionate-bipyridine, tert-butylhydroperoxide (TBHP) as oxidant, and a polar aprotic solvent (acetonitrile or acetone), demonstrated high turnover numbers (TOF) in the absence of any additives. The impact of temperature, solvent, the ratio of thymol to TBHP, different oxidants and the quantity of catalyst on the catalytic activity and product selectivity was examined. Under optimized conditions, the maximum conversion of thymol (100 %) was obtained with 100 % selectivity to thymoquinone with TBHP after 35 min at the thymol to catalyst mole ratio of 267 (TOF = 449 h−1) in acetonitrile (MeCN) at 55 °C. Based on the available evidence, this activity and selectivity to thymoquinone represent the highest reported level of performance achieved by a homogeneously copper-catalysed process.

Advancements in CdTe Thin‐Film Solar Cells: Is Doping an Effective Strategy for Performance Enhancement?

Cadmium telluride (CdTe) thin‐film solar cells that are introduced in 1970s have emerged as one of the forefront materials of the second generation‐based solar cells. They are preferred as an ideal candidate for the fabrication of reliable and economical photovoltaic systems owing to high optical absorption coefficient, nearly optimum bandgap for ensuring maximum conversion efficiency and chemical stability. The major challenges associated with these solar cells are low concentration of carriers, which limits the photovoltaic parameters notably the open‐circuit voltage and fill factor as well as short life time of absorber minority carriers. This article explores the pivotal role of doping in enhancing the electrical properties and life time of minority carriers of CdTe solar cells through extensive literature study of the complexity of mechanisms and output parameters achieved in various reported works. Doping has been systematically reviewed with emphasis on types of doping, classification of dopants into group I and group V dopants along with a concise summary of different dopants. This comprehensive review not only evaluates the recent advancements of CdTe solar cells but also addresses these issues and provides future perspectives and paves way for development of improved stable and highly efficient cells.

Mechanics-Switchable and Antiswelling Colloidal Hydrogels Inspired by the Cononsolvency Effect.

Stiffness switching hydrogels have been in high demand for intelligent devices, adhesion science, soft robotics, and flexible electronics. However, it is challenging to post-tune the mechanical properties of a hydrogel once the polymer network structure is formed. Inspired by the cononsolvency effect, we prepared a mechanics-switching colloidal hydrogel through the precipitation polymerization of methacrylamide in mixed dimethyl sulfoxide and water solvents. The colloidal network enables the hydrogels to simultaneously strengthen, stiffen, and toughen. The colloidal hydrogels not only display a broad spectrum of adjustable mechanical properties (ranging from 0.08 to 57.1 MPa) via solvent response but also accomplish reversible stiffness conversion through the solvent-tuned conformational adjustment of colloidal polymer networks, with the maximum modulus conversion reaching 1427, and exhibit solvent-responsive shape memory. Based on the stable and tight colloidal network, the hydrogels exhibit antiswelling properties in various aqueous solutions and solvents. The colloidal hydrogel would provide more possibilities in various applications, such as antiimpact protection, shape memory, electronic switches, and intelligent engineering materials. It is envisioned that this work will provide key opportunities in developing mechanics-switching and on-demand tuning of soft materials for tissue engineering, flexible electronics, and biomedical science.

Fine-Tuning Conformation of PEDOT Chains Enables Simultaneously Enhanced Conductivity, Work Function, Transmittance, and Waterproofness in PEDOT:PSS Interlayer for Highly Efficient and Stable Organic Photovoltaics.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely utilized as the hole transport layer (HTL) inorganic photovoltaics (OPVs) because of its low-temperature solution processing peculiarity, high optical transmittance, and excellent mechanical flexibility. However, the core-shell structure of PSS coated PEDOT results in relatively low conductivity, work function, transmittance and waterproofness of PEDOT:PSS interlayer, limiting the photovoltaic performance and stability of OPVs. Here, the conformation of PEDOT chains are regulated from helical benzoyl to linear quinone structure via incorporation of 2D Cd0.85PS3Li0.15H0.15dopant into the conventional PEDOT:PSS interlayer, promoting an interpenetrating network structure in PEDOT:PSS interlayer and forming an efficient hole transport channel from active layer to ITO electrode. Such features significantly improve the electrical conductivity, work function, and transmittance of PEDOT:PSS interlayer. In consequence, the maximum power conversion efficiency (PCE) of D18:L8-BO, PBDB-T:ITIC, as well as PTzBI-dF:L8-BO based OPVs ameliorated from 18.37%, 8.94%, and 15.80% to 19.26%, 10.00%, and 16.83%, respectively. The application of Cd0.85PS3Li0.15H0.15 doping PEDOT:PSS strategy demonstrates great potential for the development of strongly conductive, large-work-function, highly transparent, and excellent-waterproof PEDOT:PSS interlayer toward highly efficient and stable OPVs.

T-Shaped-N-Doped Polycyclic Aromatic Hydrocarbons: A New Concept of Dopant-Free Organic Hole-Transporting Materials for Perovskite Solar Cells.

Although metal halide perovskites are positioned as the most powerful light-harvesting materials for sustainable energy conversion, there is a need for a thorough understanding of molecular design principles that would guide better engineering of organic hole-transporting materials, which are vital for boosting the performance and stability of perovskite solar cells. To address this formidable challenge, here, we developed a new design strategy based on the curved N-doped polycyclic aromatic hydrocarbon merged with T-shaped phenazines being decorated with (phenyl)-di-p-methoxyphenylamine (OMeTAD)─N-PAH23/24 and -3,6-ditertbutyl carbazole (TBCz)─N-PAH25/26. As N-PAH23/24 exhibited satisfying thermal stability, the comparative studies performed with various experimental and simulation methods revealed a pronounced correlation between the depth of the central cyclazine core and the form of the T-shape units. This proved to be a crucial factor in controlling their π-π intermolecular interaction as well as self-assembly behavior with the perovskite layer, leading to enhanced humidity resistance, operational stability, and a maximum power conversion efficiency of 20.39% denoted for N-PAH23, which is superior to the benchmarked device with doped spiro-OMeTAD (19.23%). These studies not only resulted in optimized stability and device performance but also opened a conceptually new chemical space in the photovoltaic technology.