High Conversion Research Articles

Enzymatic Upgrading of Biomass-Derived Aldoses to Rare Deoxy Ketoses Catalyzed by Transketolase Variants.

A sustainable, convenient, scalable, one-step method for the two-carbon chain elongation of cheap and biomass-derived pentoses (l-arabinose, and 2-deoxy-d-ribose) and hexose l-rhamnose was developed to produce Cn+2 deoxy ketoses (C-7 and C-8) using transketolase, an enzyme catalyzing the quasi-irreversible transfer of a ketol group from an α-keto acid to an aldehyde. Deoxygenated ketoses - commonly obtained by chemical synthesis - were afforded through a suitable combination of both nucleophile and electrophile substrates in the presence of rationally designed TK variants. Pyruvate as nucleophile with pentose l-arabinose (C-5) as electrophile gave 1-deoxy-L-gluco-heptulose (C-7), while ß-hydroxypyruvate (HPA) as nucleophile with acceptors 2-deoxy-d-ribose (C-5) and 6-deoxy-l-mannose (l-rhamnose) (C-6) led to formation of 4-deoxy-d-altro-heptulose (C-7) and 8-deoxy-l-glycero-l-galacto-octulose (C-8), respectively. These three deoxy ketoses were easily obtained with efficient TK variants under mild conditions with complete or high substrate conversions, good to excellent yields and high diastereoselectivities. This strategy offers interesting prospects to study the biological activities of these three rare and valuable deoxy ketoses on various cellular targets.

Chloride Engineering for Boosting Perovskite Photovoltaics: Impact on Precursor Coordination, Crystallization, and Film Quality.

Perovskite solar cells (PSCs) have seen rapid advancements over the past decade, driven by their exceptional optoelectronic properties and high power conversion efficiencies. Cl-based additives strategy has significantly contributed to these advancements by enhancing crystallinity, improving preferred orientation, and optimizing the surface morphology of perovskite films. This review provides a comprehensive summary of recent advancements and insights into the critical role of Cl-based additives in perovskite photovoltaics, focusing on the mechanisms behind Cl incorporation and its effects on film and device performance. First, the impact of Cl on precursor solution coordination and colloidal characteristics is discussed. Then, how Cl-based additives influence the phase transitions of perovskites, including methylammonium lead iodide (MAPbI3), formamidinium lead iodide (FAPbI3), and 2D perovskites is examined. Furthermore, the impact of Cl-based interfacial treatments on perovskite film quality is explored. Based on these insights, the overall impact of Cl treatments is also reviewed on the properties of perovskite films. Finally, a brief overview of the remaining challenges and future perspectives are provided to guide ongoing research efforts toward optimizing Cl additive engineering for high-performance PSCs.

All-optical digital-to-analog conversion based on pulse walk-off effect

A novel approach for all-optical digital-to-analog conversion (DAC) based on the pulse walk-off effect is proposed and experimentally demonstrated. In this approach, an ultrafast optical pulse train is firstly spectrum-tailored by a spectrum-shaper to achieve the multi-wavelength pulses, serving as the sampling source for carrying serial input digital signals via intensity modulation. These modulated optical signals are then injected into a dispersion medium to introduce multi-wave pulse walk-off. Consequently, the modulated optical signals partially overlap in the time domain and the incoherent weighted intensity summation can be realized. The following intensity modulator driven by the selecting codes extracts the target signals in the right time slots. The proposed approach features all-optical structure, inter-channel error avoidance, and high conversion rate, offering a promising solution for achieving high-performance photonic DAC. A proof-of-concept experiment of a 3-bit DAC system with a conversion rate of 5 Gbps based on the pulse walk-off effect has been successfully carried out. Additionally, the system’s performance in terms of Effective number of bits (ENOB) versus modulator extinction ratio and dispersion fluctuations is also discussed in detail.

Vinylene-Linked Covalent Organic Frameworks for Visible-Light-Promoted Selective Oxidation of Styrene in Water.

Vinylene-linked COFs, as an emerging class of crystalline porous polymers, have been regarded as ideal heterogenous photocatalysts due to their ordered structure, tailored pore size, outstanding stability and fully π-conjugated structure. Unfortunately, their photocatalytic performances are usually impeded by high exciton binding energy and unsatisfactory exciton dissociation efficiency. Herein, the authorsbroke through this dilemma by arrangement of complementary donor-acceptor (D-A) pairs within the COF skeleton to improve charge transfer/separation. Two vinylene-linked COFs (TMT-BT-COF and TMT-TT-COF) are synthesized by Aldol condensation using highly photoactive thienothiophene and benzothiazole groups as donor and electron-deficient triazine units as acceptor. Photochemical/electrochemical studies as well as DFT calculation suggest that these D-A type vinylene-linked COFs endow high charge transfer efficiency and low charge recombination. As a result, both of them demonstrate remarkably catalytic activity in the oxidation of styrene to benzaldehyde with molecular oxygen, with an exceptionally high conversion rate (≥92%) and selectivity (≥90%). Intriguingly, in the presence of NaHCO3, the above COFs could photocatalyze epoxidation styrene in water, and the styrene oxide selectivity reached 53%. This work elucidates the prominent capability of vinylene-linked COFs in the photocatalytic transformation of organic compounds in aqueous media, which may pave a new avenue for their future development.

Configuration-Mediated Efficient Non-Radiative Transition for R848-Assisted Photothermal Immunotherapy to Inhibit Tumor Growth andMetastasis by AnIn Situ Tumor Vaccine Strategy.

Cancer metastasis remains a critical factor contributing to the current limitations in cancer treatment. Photothermal immunotherapy has emerged as a safe and potent therapeutic approach, demonstrating the capability to suppress tumor growth and metastasis. While researchers have extensively investigated various structural modifications to enhance photothermal conversion performance, the influence of molecular configuration has received comparatively limited attention. In this study, we synthesized two isomers, CZTBT and LVTBT, which possessed distinct configurations. LVTBT, characterized by a flatter molecular configuration, exhibited an extended absorption wavelength and a higher molar extinction coefficient. Its excited state facilitated stronger rotation for non-radiative transitions, leading to a high photothermal conversion efficiency (PCE) of 36.3%. When combined with R848, LVTBT@R848 nanoparticles (NPs)-mediated photothermal immunotherapy functioned as an in situ tumor vaccine, promoting the maturation of dendritic cells (DCs), T cell infiltration, and the differentiation of natural killer (NK) cells and memory T cells, thereby activating the strong immune response. Consequently, it significantly inhibited the growth of both primary and distant tumors, while also limiting lung metastasis. In summary, this study proposed a configuration-mediated non-radiative transition strategy for efficient photothermal immunotherapy, advancing the frontiers of organic photothermal agents (OPTAs) design and synthesis.

Configuration‐Mediated Efficient Non‐Radiative Transition for R848‐Assisted Photothermal Immunotherapy to Inhibit Tumor Growth and Metastasis by An In Situ Tumor Vaccine Strategy

Cancer metastasis remains a critical factor contributing to the current limitations in cancer treatment. Photothermal immunotherapy has emerged as a safe and potent therapeutic approach, demonstrating the capability to suppress tumor growth and metastasis. While researchers have extensively investigated various structural modifications to enhance photothermal conversion performance, the influence of molecular configuration has received comparatively limited attention. In this study, we synthesized two isomers, CZTBT and LVTBT, which possessed distinct configurations. LVTBT, characterized by a flatter molecular configuration, exhibited an extended absorption wavelength and a higher molar extinction coefficient. Its excited state facilitated stronger rotation for non‐radiative transitions, leading to a high photothermal conversion efficiency (PCE) of 36.3%. When combined with R848, LVTBT@R848 nanoparticles (NPs)‐mediated photothermal immunotherapy functioned as an in situ tumor vaccine, promoting the maturation of dendritic cells (DCs), T cell infiltration, and the differentiation of natural killer (NK) cells and memory T cells, thereby activating the strong immune response. Consequently, it significantly inhibited the growth of both primary and distant tumors, while also limiting lung metastasis. In summary, this study proposed a configuration‐mediated non‐radiative transition strategy for efficient photothermal immunotherapy, advancing the frontiers of organic photothermal agents (OPTAs) design and synthesis.

A non-dominated sorting based multi-objective neural network algorithm of ethylene glycol hydrogenation reactor in energy reduction

Artificial intelligence has revolutionized various industries, including chemical process optimization. Artificial intelligence (AI) can be applied to various ethylene glycol (EG) production aspects to improve efficiency, quality, and overall process optimization. Process optimization of dimethyl oxalate (DMO) hydrogenation to ethylene glycol (EG) is carried out to minimize/maximize conversion, energy, productivity, bare module cost (CBM), and side product in the presence of pressure and temperature variables. A non-dominated sorting-based multi-objective neural network algorithm (MONNA) is applied to tackle problem optimization for EG production. The results show that the highest productivity, minimum energy cost, side product, and highest conversion are 172 Million RM/year, 0.00600 Million RM/year, 0.0320 kmol/hr, and 99.6%, respectively. The intermediate points in the Pareto Front PF for various three-objective situations provide lower energy costs than the bi-objective function. While bi-objective optimization might seem more straightforward, the intermediate points on the Pareto Front in three-objective optimization can provide lower energy costs due to more effective balancing of trade-offs, richer exploration of the solution space, capturing complex interdependencies, and offering more robust and flexible solutions. Decision makers can use the resulting pareto to decide on the most acceptable alternative according to their preferences. The decision variable plots show that the pressure highly affected the optimal solution with the opposite action. This work’s analysis is predicted to provide insight into optimization literature for energy savings and sustainability and promote commercial growth for the industry. Identifying optimal trade-offs between various objectives, such as energy cost and productivity, can help reduce overall production costs, making the production process more competitive.

Dispersion-engineered InGaAsP/InP waveguide for high efficiency all-optical on-chip wavelength conversion

InGaAsP/InP waveguide platform offers superiority for all-optical on-chip wavelength conversion due to strong optical nonlinearity. However, a small refractive index difference between the core and cladding makes it challenging to achieve sufficient structural dispersion for phase matching. In this work, the InGaAsP multilayer waveguide and the SiN-cladded InGaAsP waveguide are investigated for optimized wavelength conversion at telecom wavelengths. Structural dispersion is effectively engineered through the incorporation of additional slot layers and a heterogeneous passivation layer. Through comparative analysis, the wavelength conversion efficiency of -4.7 dB is achieved by the SiN-cladded waveguide, which shows an improvement of 22 dB compared to traditional nanowire waveguide.

Exploring the catalytic performance of recyclable zinc indium sulfide in polymer synthesis: Well-controlled photoATRP of acrylates

Zinc indium sulfide has been used as a heterogeneous recyclable photocatalyst in visible light-induced atom transfer radical polymerization (ATRP). The photocatalyst was found to catalyze ATRP via an oxidative quenching mechanism without any additives. Polymers in high conversion and good control can be obtained. The kinetic study, light on/off experiment and the block copolymer synthesis showed the “living”/controlled nature of the polymerization. The photocatalyst can be reused for five times without obvious loss of control in the polymerization. Metal residue was not detected in the resulting polymers. This strategy provides a noval way for well-controlled polymer synthesis using recyclable visible light photocatalysis.

Preparation of two new chiral metal-organic frameworks for lipase immobilization and their use as biocatalysis in the enantioselective hydrolysis of racemic naproxen methyl ester

Considering the selective pharmacological activity of chiral drugs, it is important to develop new chiral materials to synthesize them. In this work, two new chiral MOFs (UiO-66@Np and UiO-66@Ib) were prepared by the covalent attachment of the chiral compounds (S-naproxen and S-ibuprofen) to the amine-functionalized Zr-MOF (UiO-66-NH2). Then, Candida rugosa lipase (CRL) was immobilized on these chiral MOFs to fabricate two new biocomposites (UiO-66@Np@CRL and UiO-66@Ib@CRL) as effective biocatalysts, which enable significant enhancement in the catalytic activity and enantioselectivity of lipase. The FTIR, SEM, EDX, TGA, and PXRD analyses were carried out to confirm the formation of the biocomposites. The catalytic performances of the biocomposites (UiO-66@Np@CRL and UiO-66@Ib@CRL) were evaluated in the typical hydrolysis of p-nitro-phenyl palmitate (p-NPP) and the catalytic enantioselective hydrolysis of (R,S)-naproxen methyl ester. Under optimal conditions, UiO-66@Np@CRL showed a higher enantiomeric excess of the substrate (ees) value and a 98 % and 50 % conversion rate, respectively, than that of UiO-66@Ib@CRL. Besides, an excellent enantioselectivity (E) value of 458 was obtained in the presence of the biocomposite (UiO-66@Np@CRL). In addition, it was observed that the catalytic activity, conversion rate and ees value of this composite (UiO-66@Np@CRL) remained almost unchanged in reuse after 6 months. The results showed that in enantioselective reactions, the highest conversion and enantioselectivity could be achieved when the chiral compound bound to the MOF and the model compound used are the same.

Construction of mesoporous lanthanum oxide and supported Co-N catalysts for high-efficient synthesis of furfuryl alcohol

The mesoporous lanthanum oxide materials were designed via the solvent evaporation-induced self-assembly method, and Co-N/La2O3 catalysts were prepared to evaluate performance in the reaction of furfural hydrogenation. The characterization analyses proved that Co/La2O3 and Co-2N/La2O3 catalysts had high specific surface area and open mesoporous channels (> 20nm), moreover doped nitrogen not only promoted the distribution of Co species and regulated size of metallic Co nanoparticles (~17.37nm), but also increased electron-rich Co0 (57.8%) and CoNx sites. The highest conversion (>99.9%) and selectivity (98.6%) were achieved on Co-2N/La2O3 catalyst under 140oC, 1.5MPa H2 and 3h, which was attributed to the combination of Co0 and CoNx sites enhancing the dissociation of H2 and adsorption of furfural by DFT calculation, meanwhile the doped nitrogen brought more acidic sites (~ 2.81mmol NH3/g) of Co-2N/La2O3 catalyst. Additionally, the Co-2N/La2O3 catalyst showed the stable catalytic activity for 5 recycles and excellent universality for hydrogenation reactions of biomass platform molecules.

Direct synthesis of liquid hydrocarbons from CO2 and H2 over bifunctional ZnCrOx-НZSM-5 combined and composite catalysts in a single reactor

A one-stage synthesis of gasoline fraction from CO2 and H2 was carried out on Zn-Cr–oxide-zeolite combined and composite catalysts. It was found that after oxidative and reduction treatment the catalysts contain ZnO and ZnCr2O4 phases. The one-step coprecipitation of zinc and chromium salts in the presence of zeolite allows obtaining an active bifunctional composite catalyst, each particle of which contains Zn-Cr oxide and zeolite components. A synergistic catalysis due to a closer distance of metal and acid sites increased the efficiency of such a catalyst in CO2 hydrogenation. It was found that the optimal temperature of oxidative activation of the composite catalyst is 400 ° C. With an increase in the temperature of oxidative treatment of the composite catalyst from 400 to 500°C, part of the zinc leaves the structure of the non-stoichiometric spinel and leads to a decrease in the basicity of the catalyst, which is responsible for the activation of CO2 on surface oxygen vacancies. Agglomerated ZnO particles blocked the pores and reduced their volume, as well as the specific surface of the catalyst. At the same time, the total acidity of the catalyst decreased. ZnO-species, which have hydrogenating activity, under the reaction conditions removed alkenes from the reaction cycle and thereby reduced the C5+–selectivity of the composite catalyst. Among the studied catalysts, the ZnCrOx-НZSM-5/Al2O3(400) composite catalyst in the tail-gas recirculation mode at 380°C and 10 MPa demonstrated high CO2 conversion of 25% and high selectivity for C5+–HCs of 53 wt% with a high content of isoalkanes 71 wt% for 60 hours. The methane content in the tail-gas did not exceed 3 vol%. The results obtained will be used to develop approaches to creating effective catalysts for the one-stage CO2 hydrogenation into valuable petrochemical products.

Quasi-solid-state monolithic DSSCs with optimized spacer layers and composite electrolytes for better efficiency and stability

In this study, high-performance quasi-solid-state monolithic dye-sensitized solar cells (QS-M-DSSCs) were designed using an optimized spacer layer architecture to enhance electrolyte transport and improve cell performance. Spacer layers, made from a combination of zirconium oxide (ZrO2) and titanium dioxide (TiO2), were precisely tuned to reduce mass-transport limitations. A 5.2 μm thick ZrO2/TiO2 layer provided good light reflectance and incident photon-to-current conversion efficiency compared to double layers of either material alone. Electrochemical impedance spectroscopy analysis of the m-DSSCs revealed that this architecture (photoelectrode TiO2 layer/ZrO2/TiO2 spacer layer/counter electrode catalyst layer) significantly increased recombination resistance, leading to an improvement in open-circuit voltage. As a result, acetonitrile iodide liquid-DSSCs using N719 dye achieved a high power conversion efficiency (PCE) of 8.45 %, surpassing cells with alternative spacer designs. For fully printable QS-M-DSSCs, printable gel electrolytes (PGEs) composed of polyethylene oxide and polymethyl methacrylate in 3-methoxypropionitrile (MPN) were employed. A 5 wt% PEO/PMMA composition demonstrated fast and efficient penetration of the PGEs through spacer layers. Moreover, incorporation of 4 wt% TiO2 nanoparticles into PGEs further enhanced their electrochemical properties, achieving a PCE (7.31 %) higher than cells with liquid electrolytes (6.72 %). QS-M-DSSCs demonstrated greater stability than liquid-state DSSCs.

Mo–V–Al–K–O catalyst for low-temperature oxidative dehydrogenation of propane

Compared with propane dehydrogenation (PDH) technology, oxidative dehydrogenation (ODH) of propane is an effective way to break through the thermodynamic constraints, which has changed the endothermic reaction into exothermic. Meanwhile, coking in PDH was significantly reduced by the presence of an oxidant in ODH of propane. Therefore, ODH of propane has attracted wide interest and has been studied in recent years. However, the contradiction between the conversion of propane and the selectivity of propene was the intrinsic problem of ODH of propane that required further study. In this work, a novel aluminum/potassium-doped mixed metal oxide catalyst Mo1V0.5Al0.02K0.03Ox was synthesized using a simple co-impregnation method, whose selectivity for propene (83.2 %) and conversion of propane (12.7 %) at 300 °C were the best among all other alkali metal/alkaline-earth metal-doped catalysts. The further discussion illustrated that doping potassium and alumina could synergistically adjust the density of acid sites on the catalyst, establishing an equilibrium between high propane conversion and the ideal propene selectivity. After modification, the density of Brønsted acid decreased, leading to an enhancement in the selectivity of propene. Simultaneously, the addition of steam in the feed gas promotes propene to oxygenates and improves the conversion of propane under the condition of constant contact time.

Supramolecular macrocycle grafted Nb-MXene nanosheets constructing self-supporting framework for high-performance lithium-sulphur batteries

The advancement of lithium-sulphur (Li-S) batteries with high-energy density has been hindered by the high energy conversion barrier of sulphur and the shuttle effect of polysulfides. In this study, we successfully graft monocarboxylic pillar[5]arene (PA5-COOH) onto niobium carbide MXene (Nb2CTx) through an esterification reaction to obtain the PA5-COOH/Nb2C hybrid multi-functional separator. The incorporation of organic molecules increases the interlayer spacing, creating more active sites for capturing polysulfides. Through a combination of experimental and theoretical calculations, we find that the presence of the organic macromolecular structure can facilitate rapid polysulfide conversion, while Nb2CTx provides support sites for PA5-COOH and its larger specific surface area helps mitigate sulphur volume changes. By equipping Li-S batteries with a PA5-COOH/Nb2C separator, the Li-S battery supports an impressive reversible specific capacity of 1317mAh g−1 at 0.2C and demonstrates exceptional rate performance (303 mAh g−1 at 10C). The incorporation of the PA5-COOH/Nb2C hybrid separator expands the application potential of organic macrocyclic molecules and presents a stable self-support structure for developing high-performance lithium-sulphur batteries using macrocycle organic molecules.

Impact of Self-Assembled Monolayer Structural Design on Perovskite Phase Regulation, Hole-Selective Contact, and Energy Loss in Inverted Perovskite Solar Cells

Recent studies have shown that self-assembled molecule (SAM)-based hole-selective contacts (HSCs) offer a promising solution to the challenges faced by perovskite solar cells (PVSCs), including minimal material consumption, scalable production, high interface stability, and the use of environmentally friendly solvents. In this study, the efficacy of two designs of SAMs (Cz and PA) as HSCs in inverted PVSCs was investigated by comparing them with the conventional MeO-2PACz (MeO) SAM. Surface analyses showed that the surface of PA is smoother than that of Cz, which helps to reduce interfacial defects. Subsequent perovskite deposition exhibited a reduced formation of the PbI2 phase, incidiating that its phase modulation ability is superior to that of MeO. Further analyses demonstrate the superior charge extraction ability of PA as a result of reduced interfacial defects and non-radiative recombination at the HSC/perovskite interface. By further coupling with phenethylammonium iodide (PEAI) surface passivation, both interfaces of the perovskite film were optimized and the inverted ((FAPbI3)0.85(MAPbBr3)0.15)0.95(CsPbI3)0.05 (bandgap = 1.62eV) PVSC achieves a high power conversion efficiency (PCE) of 23.3% and a very high open-circuit voltage of 1.227V due to the largely reduced energy loss. In addition, the PA PVSC exhibits enhanced long-term thermal stability at 85°C in a nitrogen atmosphere.

Experimental study of a backward bent duct buoy wave energy converter: Effects of the air chamber and center of gravity height

The backward-bent duct buoy (BBDB) wave energy converter (WEC) is a floating oscillating water column (OWC) device with high conversion efficiency and low mooring requirements. This study experimentally investigates the effects of air chamber volume, chamber top shape, and center of gravity height on the wave energy capture performance of BBDB WEC. The results indicate that increasing the air chamber's volume enhances conversion performance. When the air chamber volume is increased from 0.0162 m³ to 0.0233 m³, the maximum capture width ratio (CWR) increases by 0.14 and 0.13 at wave amplitudes of 0.015 m and 0.025 m, respectively. An oblique cut prism chamber improves performance under low wave periods. When using a chamber with an inclined top, conversion performance exceeds that of a rectangular chamber, with the maximum CWR increasing from 1.09 to 1.40 at a wave height of 0.015 m and from 0.82 to 1.01 at a wave height of 0.025 m. Additionally, changes in center of gravity height primarily affect conversion efficiency during the pitch resonance period. These findings contribute to the structural optimization and performance enhancement of BBDB WECs.

Facile access to highly functionalized polyacrylamide with ultra-high molecular weight: Multicomponent initiators-based free radical polymerization

We report a novel multicomponent initiators-based copolymerization strategy for synthesizing of acrylamide (AM) and 2-acrylamide-2-methylpropane sulfonic acid (AMPS) copolymers, denoted by P(AM-co-AMPS), with an ultra-high content of AMPS (≥ 50 mol%) and an ultra-high molecular weight (> 107 g/mol), while achieving a high conversion rate of monomer (∼100.0%). The multicomponent initiators contain a redox couple, an azo compound, and a catalyst. Our investigation into the mechanism suggested that the synergistic effect in different rate constant for initiator decomposition between redox and azo initiators was responsible for actualizing ultra-high molecular weight copolymers with high conversion rates of monomer. Moreover, copolymers with 75 mol% and 100 mol% of AMPS were synthesized to verify the advantage of the multicomponent initiators-based strategy, both of which exhibited ultra-high molecular weight and ultra-high monomer conversion rates. This study fills a long-standing gap in research on the polyacrylamide family by providing highly functionalized P(AM-co-AMPS) with an ultra-high molecular weight. Moreover, it reveals how multicomponent initiators reconcile the contradiction between the ultra-high molecular weight and the high conversion rate in copolymerization.

A Survey Paper on Plastic Solar Cell Technology

The demand of energy is increasing day by day so non-conventional source of energy has to be used. Sun is the nonconventional source of energy. Conventional solar panels convert solar energy into electrical energy. A plastic solar cell is the type of photovoltaic that makes use of organic electronics dealing with conductive organic polymers or small molecules for light absorption and charge transport to produce electricity from sunlight by the photovoltaic effect. Polymers Provide the Advantage of Solution Processing at Room Temperature, which is Less Expensive and Enables One to Use Plastics. Therefore, If Silicon Is Replaced with Polymer Nanowires, The Solar Cell Would Be Much Lighter and Ultimately Less Costly. These Solar Cells are Thin, Several Microns in Diameter, and Scavenge All the Rays from the Sun's Radiation. Plastic Solar Cell Technology is Based on Conjugated Polymers and Molecules. Polymer Solar Cells have Generated Considerable Interest Since it Provides Environmentally Friendly, Flexible, Lightweight, Low Cost, Possibility of High-Efficiency Solar Cells in the Last Couple of Decades. Plastic Solar Cells are More Efficient and Viable in Usage. This dissertation focuses on the development and optimization of plastic solar cell technology, in particular this potential towards flexible, lightweight, and cost-effective alternative sources to traditional silicon-based solar cells. The focus of the present research work is to find optimum organic materials for higher efficiency and stability in plastic solar cells, varying from conjugated polymers to small organic molecules. Some of the main goals are improving the charge transport mechanisms and optimizing the architecture of devices through state-of-the-art techniques of fabrication, like roll-to-roll printing and layer-by-layer deposition. The other key aspect is that the project assesses the environmental aspects and lifecycle of plastic solar cells to ensure an environmentally friendly production process. Huge preliminary results were achieved at high power conversion efficiencies and durability has been greatly improved, targeting very wide spread application from portable electronics up to building-integrated photovoltaics. Therefore, the discovery of plastic solar cells might be a major step for applicable solutions in renewable energy and towards overcoming the world's increasing energy challenges.

Dual-interface passivation to improve the efficiency and stability of inverted flexible perovskite solar cells by in-situ constructing 2D/3D/2D perovskite double heterojunctions

Perovskite solar cells (PSCs) have demonstrated considerable potential as a promising photovoltaic technology. Nevertheless, the continued advancement is impeded by the presence of interfacial defects, which give rise to nonradiative recombination and ion migration. In this work, we demonstrate a simple and effective method to in-situ construct 2D/3D/2D perovskite double heterojunctions for effective passivation of defects and mitigation of ion migration in 3D perovskites. As a result, the inverted double-heterojunction PSCs exhibited a high power conversion efficiency (PCE) of 24.08 % with a low VOC loss of 0.37 V due to the minimal nonradiative recombination by dual-interface passivation. The stability of double-heterojunction devices has been significantly improved, maintaining 92 % of the initial value after 3000 h of storage under indoor light in a N2 atmosphere. Especially, the 2D/3D/2D perovskite double heterojunctions are applicable to flexible PSCs (FPSCs) to enhance both PCE and mechanical stability by effective residual stress release. Consequently, the FPSCs demonstrated a PCE of 21.58 % while retaining 86 % of the initial PCE even after undergoing a multi-cycle bending test for 10,000 cycles.