Photoconversion Efficiency Research Articles

Stepwise Photochromism of Large Macrocycles Incorporating Two Negative Photochromic Units.

Macrocyclic photochromic molecules incorporating multiple photochromic units are known to exhibit cooperative and nonlinear photochromic reactions among distinct photochromic components. While extensive research has concentrated on positive photochromic molecules, this study presents a pioneering attempt in synthesizing macrocyclic photochromic molecules that integrate negative photochromic units. Binaphthyl-bridged phenoxyl imidazolyl radical complex, BN-PIC, exhibits unique negative photochromism in which the thermally stable colored isomer converts to the metastable colorless isomer via a short-lived biradical upon visible-light irradiation. Macrocyclic biphotochromic molecules incorporating two BN-PIC units were synthesized and the effects of ring strain on the photochromic properties including the photoconversion efficiencies and the rates of the thermal reverse reaction were investigated. The photokinetic study of these macrocyclic biphotochromic molecules demonstrated that the structural distortion of the ring caused by the isomerization of one photochromic unit significantly influenced the photoisomerization efficiency and the rate of the thermal reverse reaction of the other photochromic unit.

Anodized commercial galvanized grids decorated with Ag nanospheres and Cu worm-like nanorods for photoelectrochemical water splitting

The current work introduces novel and low-cost AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes for the photoelectrochemical (PEC) water-splitting reaction. The photoanodes were fabricated by anodizing commercial galvanized grids(A@CGGs) in the sodium carbonate solution followed by deposition of Ag or Cu through a simple electroless substitution. Surface studies showed that AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes have a unique morphology including Ag nanospheres (AgNSs) and Cu worm-like nanorods (CuNRs) with huge surface area. The UV-VIS diffuse reflectance spectra (DRS) of AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes displayed the lower band gap energies of 2.4 eV, and 2.83 eV respectively, which compared to 3.91 eV for the A@CGGs, showing excellent photoanodic behavior for AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes. Investigations of photoelectrochemical water-splitting under visible light irradiation showed that the production amount of H2 from AgNSs-A@CGGs and CuNRs-A@CGGs photoanodes was about 18570 and 6895 μmol h−1 cm−2 respectively. Moreover, AgNSs-A@CGGs showed 15.27 and 5.0 times higher photoconversion efficiency than CGGs and A@CGGs respectively. In this study, the introduced photoanode grids are expected to be used as cheap and industrial photoanodes for PEC water-splitting and hydrogen gas production.

Iron Oxide Nanoparticles: Parameters for Optimized Photoconversion Efficiency in Synergistic Cancer Treatment.

Photothermal therapy (PTT) can overcome cancer treatment resistance by enhancing the cell membrane permeability, facilitating drug accumulation, and promoting drug release within the tumor tissue. Iron oxide nanoparticles (IONPs) have emerged as effective agents for PTT due to their unique properties and biocompatibility. Approved for the treatment of anemia, as MRI contrast agents, and as magnetic hyperthermia mediators, IONPs also offer excellent light-to-heat conversion and can be manipulated using external magnetic fields for targeted accumulation in specific tissue. Optimizing parameters such as the laser wavelength, power density, shape, size, iron oxidation state, functionalization, and concentration is crucial for IONPs' effectiveness. In addition to PTT, IONPs enhance other cancer treatment modalities. They improve tumor oxygenation, enhancing the efficacy of radiotherapy and photodynamic therapy. IONPs can also trigger ferroptosis, a programmed cell death pathway mediated by iron-dependent lipid peroxidation. Their magneto-mechanical effect allows them to exert a mechanical force on cancer cells to destroy tumors, minimizing the damage to healthy tissue. This review outlines strategies for the management of the photothermal performance and PTT efficiency with iron oxide nanoparticles, as well as synergies with other cancer therapies.

Improving the efficiency above 35 % of MoS2-based solar cells by through optimization of various wide-bandgap S-chalcogenides ETL

Molybdenum disulfide (MoS2)-based photovoltaic cells are increasingly attracting researchers’ due to their outstanding semiconducting properties. Single junction MoS2 based solar cell have been investigated with three distinct electron transport layer (ETL) layers made of SnS2, In2S3 and ZnSe in detail with and without back surface field (BSF). A thorough numerical analysis has been conducted of the effects of band alignment, defect density, absorber layer thickness, buffer layer thickness, interface defect density, electron and hole concentration, generation and recombination, open circuit voltage (VOC), short circuit current (JSC), fill factor (FF), and power conversion efficiency (PCE) via SCAPS-1D simulation software. The MoS2 based solar cell produced the photo conversion efficiency (PCE) of 24.77 % with VOC of 0.913 V, JSC of 31.274 mA/cm2, and FF of 86.77 % without BSF. On the other hand, after in depth analysis, according to simulation results, SnS2 ETL produced the highest PCE of 35.60 % than ZnSe(33.56 %) and In2S3(34.94 %) ETL with VOC of 1.07 V, JSC of 37.55 mA/cm2, and FF of 88.80 % with inserting only 30 nm V2O5 BSF layer. The suggested research might provide information and a workable strategy for producing a MoS2-based thin-film solar cell that is affordable.

Carbon dots-Zno/TiO2 ternary nanocomposite as a proficient material to enhance the performance of natural DSSC

A novel sustainable approach for enhancing the efficiency of dye-sensitized solar cells (DSSCs) involves the utilization of a combination of ZnO and carbon dots (CDs) derived from Citrus medica fruit extract, along with microwave-synthesized TiO2 nanoparticles for the preparation of the photoanode. Natural dyes such as Hibiscus rosa-sinensis and Allium Cepa peel are employed as sensitizers to reduce production costs. This co-activation method has demonstrated a significant improvement in the output parameters of the devices. Notably, the photoanode co-activated with ZnO-CD composite (ZnO-CD/TiO2) exhibits the most favorable output parameters when combined with Hibiscus rosa-sinensis dye (open circuit voltage (Voc) = 0.80 V, short circuit current density (Jsc) = 6.62 mA/cm2, fill factor (FF) = 64.20 %, photo conversion efficiency (PCE) = 3.40 %) and Allium Cepa peel dye (Voc = 0.81 V, Jsc = 6.79 mA/cm2, FF = 65.70 %, PCE = 3.61 %). When paired with Allium Cepa dye, the CD modified photoanode (CD/TiO2) offers Voc = 0.73 V, Jsc = 6.64 mA/cm2, FF = 61.27 % and PCE = 2.97 %. Similarly, when combined with Hibiscus rosa-sinensis dye, the output parameters of the CD/TiO2 photoanode are Voc = 0.72 V, Jsc = 6.54 mA/cm2, FF = 64.4 % and PCE = 3.03 %. In comparison to all tested devices, the unmodified photoanode (TiO2) displayed the lowest performance, with parameters such as Voc = 0.59 V, Jsc = 6.45 mA/cm2, FF = 52.5 %, PCE = 2.10 % using Allium Cepa peel dye, and Voc = 0.66 V, Jsc = 6 mA/cm2, FF = 51.60 %, PCE = 2.04 % using Hibiscus rosa-sinensis dye. Furthermore, the co-activation process has been shown to enhance the stability of the devices. While the unmodified photoanodes ceased to operate after eight days, the ZnO-CD composite co-activated photoanodes retained their initial efficiencies up to 61.50 % and 68.53 % with the Allium Cepa peel dye and Hibiscus rosa-sinensis dye, respectively. Therefore, this study underscores the potential of the synthesized composite material in enhancing the performance of natural DSSCs.

Stable lead free perovskite solar cells based on bismuth doped perovskite materials

The inclusion of lead in the Champion perovskite material MAPbI3 is a detrimental factor in the commercialization of lead based perovskite solar cells. This is mainly due to the toxicity of lead and also due to degradation of MAPbI3 in ambient condition into hazardous chemicals which are toxic to the environment [1]. Due to these factors, though the Hybrid Organic Inorganic Lead based PSCs exhibit excellent photovoltaic effect and photo conversion efficiency (PCE), yet numerous theoretical and experimental studies have been done to replace lead with suitable elements such as Sn, Ge, Bi etc. This research work focusses on replacing Pb from MAPbI3, with different wt% of Bi such as 1%, 2%, 4% and 8% and analyzing its effect on the stability and efficiency of the PSC. These solutions of Bi doped perovskite are coated on the FTOs and are fabricated under room ambient condition in the sandwich structure. The results exhibit lower efficiency of Bismuth doped PSCs but it shows remarkable stability comparable to that of MAPbI3.

A simple method to prepare and characterize ZnO/V2O5 nanostructure thin films for photoelectrochemical and photocatalytic uses in visible light

In this research, we investigated the enhancement of the photocatalytic efficiency of ZnO nanorods by incorporating vanadium pentoxide (V2O5). Zinc oxide (ZnO) nanorods were initially prepared by the chemical bath deposition (CBD) method. Subsequently, vanadium pentoxide (V2O5) nanoparticles, produced by laser ablation, were deposited onto the ZnO nanorods via drop casting. Scanning electron microscopy (SEM) images verified that ZnO grew in the morphology of nanorods and nanotubes, while V2O5 exhibited the structure of tree leaves and nanoparticles. The XRD technique was used to investigate the crystalline structure of the produced ZnO/ V2O5 nanostructure. The high band gap in ZnO limits the efficiency of photocatalysis under visible light. Building a core–shell structure with materials such as V2O5 can boost their performance in such conditions. The prepared samples appeared photodegradation rate of the MB dye reached 39% after 9 h of exposure to visible light. The photoelectrochemical cell measurement of the prepared ZnO/ V2O5 nanostructures demonstrated a positive response to light and achieved a relatively high photoconversion efficiency of 0.084% at 0.35 V, surpassing the results of earlier investigations. The M-S analysis revealed that the ZnO/ V2O5 nanostructure thin films exhibited n-type conductivity, characterized by a negative flat band potential VFB.

Synthesis and Characterization of Multifunctional Symmetrical Squaraine Dyes for Molecular Photovoltaics by Terminal Alkyl Chain Modifications

Novel far-red sensitive symmetric squaraine (SQ) dyes with terminal alkyl chain modifications were designed, synthesized, and characterized, aiming towards imparting multifunctionalities such as photosensitization, dye aggregation prevention, and source of electrolyte components. The dye sensitizer SQ-80 with alkyl chain terminal modifications consisting of 1-methylimidazolium iodide was designed and synthesized as a new dye sensitizer for DSSCs based on symmetric SQ-4 without any terminal modification used as reference. Upon adsorption on the mesoporous TiO2 surface, SQ-80 demonstrated reduced dye aggregation and stronger binding to the TiO2 surface, leading to enhanced durability of DSSCs. Apart from the most common photosensitization behavior, the newly designed dye demonstrated multifunctionalities such as aggregation prevention and electrolyte functionality, utilizing iodine-based redox electrolytes in the presence and absence of I2 and LiI additives. In the absence of LiI and I2, a mixture of SQ-77 with alkyl chain terminal modifications consisting of iodide and SQ-80 demonstrated a photoconversion efficiency of 1.54% under simulated solar irradiation, which was about six times higher compared with the reference dye SQ-4 (0.24%) (having no alkyl chain terminal modification).

Photo-rechargeable zinc-ion battery using highly ordered and vertically oriented C@VO2/ZnO microrod arrays

Development of photo-rechargeable batteries is a potential resolution for supplying off-grid solar power system in remote locations. Here, we present a photo-rechargeable zinc-ion battery (PRZIB) that can be directly recharged by the light without external photovoltaic cells and controllers. A highly ordered and vertically oriented ZnO microrod arrays (ZMRAs) were prepared using hydrothermal method in micron-scale patterned ZnO substrate defined by lithographic technology, which are used to incorporate with carbon encased vanadium oxide (C@VO2) nanocomposite to form a large specific surface area of three-dimensional network of C@VO2/ZnO heterojunction. PRZIB was assembled using C@VO2/ZMRAs structure as the photovoltaics as well as intercalation host for Zinc-ions, which demonstrates a photo-conversion efficiency of 3.3 % and gravimetric capacities of 286.0 mAh g−1 and 339.3 mAh g−1 at 500 mA g−1 in dark and light conditions. An excellent long-term cycling stability was achieved with a capacity retention of 88.79 % after 300 cycles at 1000 mA g−1 in dark condition. It is suggested that the distinctive morphologies and structure of C@VO2/ZMRAs provide effective strategies for enhancing photo-electrochemical redox reaction kinetics.

Enhancing PEC hydrogen generation efficiency: Robust ZnO-GaN hierarchical nanowires loaded with NiS for superior charge separation and transportation

We present a method for the sequential fabrication of a three-dimensional hierarchical structure, comprising ZnO nanowires (NWs) grown atop Vapor-Liquid-Solid (VLS) GaN NWs using Metal Organic Chemical Vapor Deposition (MOCVD) for applications in photoelectrochemical water splitting (PEC-WS). To enhance the PEC performance and photostability of the system, we performed NiS anchoring. The optimized 60 NiS/ZnO-GaN hierarchical nanowires (HNWs) exhibited a remarkable 23-fold enhancement (1.62 %) in photoconversion efficiency at 0.75 V vs reversible hydrogen electrode (RHE) compared to GaN NWs passivated with ZnO deposited by atomic layer deposition (ALD) (0.07 %), alongside an 18.9-fold increase in photocurrent density (7.6 mAcm−2 @ 1.23 V vs RHE). Additionally, these hierarchical structures demonstrated exceptional photostability over a period of 10 hours (36000 s) at 0.8 V vs RHE. The hierarchical assembly is crucial in achieving high photoconversion efficiency and photostability. The rational design of hierarchical NW photoanodes synergistically enhances both photocurrent and photostability, paving the way for facile integration of II-VI with III-V materials and potentially unlocking advancements in next-generation energy harvesting and conversion devices.

Exploring Multi‐Level ETL and HTL Configurations for High‐Efficiency Lead‐Free Cs2AgBiBr6 Double Perovskite Solar Cells: A Design and Simulation Study

Cs2AgBiBr6 is a promising lead‐free double perovskite solar cells (PSCs) material. Its full potential has yet to be realized due to issues with its large band gap and the optimization of the alignment of the electron transport layer (ETL) and hole transport layer (HTL). The photovoltaic performance of Cs2AgBiBr6‐based devices has been optimized using ZnO, IGZO, TiO2, WS2, PCBM, and C60 ETLs and Cu2O, CuScN, CuSbS2, NiO, P3HT, PEDOT: PSS, Spiro MeOTAD, CuI, CuO, V2O5, CBTS, and CFTS HTLs. It has been observed by simulation study that Cs2AgBiBr6‐based devices exhibit remarkably high photoconversion efficiency when combined with certain ETLs. To better understand the performance, we examine how the best device structures are affected by the absorber and ETL thickness, ETL carrier density, series and shunt resistance, generation, and recombination rate. The findings suggest that TiO2 and ZnO ETLs, in conjunction with CBTS HTL, exhibit good potential for producing high‐efficiency (η > 13%) Cs2AgBiBr6‐based heterojunction solar cells with an ITO/ETL/Cs2AgBiBr6/CBTS/Au device structure. Optimization of the valence band offset (VBO) at the CBTS/Cs2AgBiBr6 interface reveals that reduced VBO value has a beneficial impact on the performance of the solar cell. This modeling work gives a prospective route for manufacturing lead‐free Cs2AgBiBr6 PSCs.

Hydrothermal and electrochemical synthesis of Fe2O3 and ZnFe2O4/Fe2O3 photoanodes for photoelectrochemical applications: An experimental and theoretical study

Hematite (Fe2O3) is commonly utilized in the fabrication of photoelectrochemical cells for water-splitting reaction. However, its relatively low efficiency has highlighted the necessity for enhancements in Fe2O3-based photoanodes. In addressing this issue, this study implemented the addition of ZnFe2O4. The pure Fe2O3 was synthesized onto a Fluorine-doped Tin Oxide coated glass by the hydrothermal process, followed by the synthesis of various ZnFe2O4/Fe2O3 heterostructures using electrochemical deposition techniques. The thin film’s composition, surface morphology, and chemical species of the products were analyzed using X-ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, and X-ray Photoelectron Spectroscopy, respectively. The performance of the Fe2O3-based photoanode was compared to that of various ZnFe2O4/Fe2O3 photoanodes through photoelectrochemical studies. Results indicated that a 50 s electrochemical deposition of ZnFe2O4 on Fe2O3 yielded the highest photoconversion efficiency. Additionally, Density Functional Theory was employed to investigate the electron energy level of ZnFe2O4, revealing alignment with the properties of Fe2O3. Theoretical analysis showed that the Fermi energy of ZnFe2O4 exceeded that of Fe2O3, suggesting a preferable direction for electron transfer from ZnFe2O4 to Fe2O3 which was in consistent to the Mott-Schottky analysis. The performance of the overall ZnFe2O4/Fe2O3 heterostructure photoanodes demonstrated greater efficiency compared to pristine Fe2O3.

Growth rate of AL2O3 Thin Film by Liquid Phase Deposition as an Anti-reflection Coating Layer on Crystalline Silicon for Solar Cell Applications

The fabrication of photovoltaic (PV) device requires that surface reflectance of solar cells has to be minimized to achieve higher photo-conversion efficiency (PCE). Antireflection coating layer is deposited on the surface of a p-type crystalline silicon material to reduce the surface reflections of solar radiation and increase its absorption for efficient solar cell application. In this work, aluminum oxide thin film by liquid phase deposition (LPD-Al2O­3) is synthesized from combined solution of aluminum sulfate octadecahydrate (Al2(SO4)3·18H2­O) and sodium carbonate (NaHCO3) with pH of 3.1. Some samples of p-type (100) crystalline silicon (c-Si) wafers of resistivity 1 – 10 mΩ were immersed inside the growth liquid of LPD-Al2O­3 thin film for 1hr – 2.5 hours. This is followed by annealing the samples at a temperature of 450oC, the deposition rate is faster in the range 1 – 1.5 hours is about 35nm/hr. As the growth time increases, the growth rate of the film decreases and remains nearly constant at about 10 nm/hour at 1 – 2 hours. When the growth time exceeds 2 hours, the film thickness remains unchanged showing that the liquid has lost in growth ability. The weighted average reflection (%) of planar c-Si is reduced from 44.9 % to 29.6 % after deposition of the LPD-Al2O­3 for 2.5 hours growth time, indicating a 34.1 % reduction in reflection within wavelength region of 300–1100 nm. While the root means square (RMS) surface roughness of 36.5 nm was also recorded at the highest growth time of 2.5 hours. This shows the effect of thicker LPD-Al2O­3 thin film layer increases the anti-reflecting coating property of the material.

Growth rate of AL2O3 Thin Film by Liquid Phase Deposition as an Anti-reflection Coating Layer on Crystalline Silicon for Solar Cell Applications

The fabrication of photovoltaic (PV) device requires that surface reflectance of solar cells has to be minimized to achieve higher photo-conversion efficiency (PCE). Antireflection coating layer is deposited on the surface of a p-type crystalline silicon material to reduce the surface reflections of solar radiation and increase its absorption for efficient solar cell application. In this work, aluminum oxide thin film by liquid phase deposition (LPD-Al2O­3) is synthesized from combined solution of aluminum sulfate octadecahydrate (Al2(SO4)3·18H2­O) and sodium carbonate (NaHCO3) with pH of 3.1. Some samples of p-type (100) crystalline silicon (c-Si) wafers of resistivity 1 – 10 mΩ were immersed inside the growth liquid of LPD-Al2O­3 thin film for 1hr – 2.5 hours. This is followed by annealing the samples at a temperature of 450oC, the deposition rate is faster in the range 1 – 1.5 hours is about 35nm/hr. As the growth time increases, the growth rate of the film decreases and remains nearly constant at about 10 nm/hour at 1 – 2 hours. When the growth time exceeds 2 hours, the film thickness remains unchanged showing that the liquid has lost in growth ability. The weighted average reflection (%) of planar c-Si is reduced from 44.9 % to 29.6 % after deposition of the LPD-Al2O­3 for 2.5 hours growth time, indicating a 34.1 % reduction in reflection within wavelength region of 300–1100 nm. While the root means square (RMS) surface roughness of 36.5 nm was also recorded at the highest growth time of 2.5 hours. This shows the effect of thicker LPD-Al2O­3 thin film layer increases the anti-reflecting coating property of the material.

Understanding of Defect Passivation Effect on Wide Band Gap p-i-n Perovskite Solar Cell.

The wide band gap perovskite solar cells (PSCs) have attracted considerable attention for their great potential as top cells in high efficiency tandem cell application. However, the photovoltaic performance and stability of PSCs are constrained by nonradiative recombination, primarily stemming from defects within the bulk and at the interface of charge transport layer/perovskite and phase segregation. In this study, we systematically investigated the effects of 2-thiopheneethylammonium chloride (TEACl) on a wide band gap (∼1.67 eV) Cs0.15FA0.65MA0.20Pb(I0.8Br0.2)3 (CsFAMA) perovskite solar cell. TEACl was employed as a passivation layer between the perovskite and electron transport layer (ETL). With TEACl treatment, charged defects responsible for sub-band absorption and electrostatic potential fluctuation were effectively suppressed by the passivation of bulk defects. The incorporation of TEACl, which led to the formation of a TEA2PbX4/Perovskite (2D/3D) heterojunction, facilitated better band alignment and effective passivation of interface defects at the ETL/CsFAMA. Owing to these beneficial effects, the TEACl passivated PSC achieved a photo conversion efficiency (PCE) of 19.70% and retained ∼85% of initial PCE over ∼1900 h, surpassing the performance of the untreated PSC, which exhibited a PCE of 16.69% and retained only ∼37% of its initial PCE.

Coherent Transfer of Lattice Entropy via Extreme Nonlinear Phononics in Metal Halide Perovskites

Entropy transfer in metal halide perovskites, characterized by significant lattice anharmonicity and low stiffness, underlies the remarkable properties observed in their optoelectronic applications, ranging from solar cells to lasers. The conventional view of this transfer involves stochastic processes occurring within a thermal bath of phonons, where the lattice arrangement and energy flow from higher- to lower-frequency modes. Here, we unveil a comprehensive chronological sequence detailing a conceptually distinct coherent transfer of entropy in a prototypical perovskite CH3NH3Pbl3. The terahertz periodic modulation imposes vibrational coherence into electronic states, leading to the emergence of mixed (vibronic) quantum beat between approximately 3 and 0.3 THz. We highlight a well-structured bidirectional time-frequency transfer of these diverse phonon modes, each developing at different times and transitioning from high to low frequencies from 3 to 0.3 THz, before reversing direction and ascending to around 0.8 THz. First-principles molecular dynamics simulations disentangle a complex web of coherent-phononic coupling pathways and identify the salient roles of the initial modes in shaping entropy evolution at later stages. Capitalizing on coherent entropy transfer and dynamic anharmonicity presents a compelling opportunity to exceed the fundamental thermodynamic (Shockley-Queisser) limit of photoconversion efficiency and to pioneer novel optoelectronic functionalities. Published by the American Physical Society 2024

Direct Z-scheme heterojunction impregnated MoS2–NiO–CuO nanohybrid for efficient photocatalyst and dye-sensitized solar cell

In this present work, the preparation of ternary MoS2–NiO–CuO nanohybrid by a facile hydrothermal process for photocatalytic and photovoltaic performance is presented. The prepared nanomaterials were confirmed by physio-chemical characterization. The nanosphere morphology was confirmed by electron microscopy techniques for the MoS2–NiO–CuO nanohybrid. The MoS2–NiO–CuO nanohybrid demonstrated enhanced crystal violet (CV) dye photodegradation which increased from 50 to 95% at 80 min; The degradation of methyl orange (MO) dye increased from 56 to 93% at 100 min under UV–visible light irradiation. The trapping experiment was carried out using different solvents for active species and the Z-Scheme photocatalytic mechanism was discussed in detail. Additionally, a batch series of stability experiments were carried out to determine the photostability of materials, and the results suggest that the MoS2–NiO–CuO nanohybrid is more stable even after four continuous cycles of photocatalytic activity. The MoS2–NiO–CuO nanohybrid delivers photoconversion efficiency (4.92%) explored efficacy is 3.8 times higher than the bare MoS2 (1.27%). The overall results indicated that the MoS2–NiO–CuO nanohybrid nanostructure could be a potential candidate to be used to improve photocatalytic performance and DSSC solar cell applications as well.

Oxygen-Mediated (0D) Cs4PbX6 Formation during Open-Air Thermal Processing Improves Inorganic Perovskite Solar Cell Performance.

The desire to commercialize perovskite solar cells continues to mount, motivating the development of scalable production. Evaluations of the impact of open-air processing have revealed a variety of physical changes in the fabricated devices─with few changes having the capacity to be functionalized. Here, we highlight the beneficial role of ambient oxygen during the open-air thermal processing of metastable γ-CsPbI3-based perovskite thin films and devices. Physiochemical-sensitive probes elucidate oxygen intercalation and the formation of Pb-O bonds in the CsPbI3 crystal, entering via iodine vacancies at the surface, creating superoxide (O2-) through electron transfer reactions with molecular oxygen, which drives the formation of a zero-dimensional Cs4PbI6 capping layer during annealing (>330 °C). The chemical conversion permanently alters the film structure, helping to shield the subsurface perovskite from moisture and introduces lattice anchoring sites, stabilizing otherwise unstable γ-CsPbI3 films. This functional modification is demonstrated in γ-CsPbI2Br perovskite solar cells, boosting the operational stability and photoconversion efficiency of champion devices from 12.7 to 15.4% when annealed in dry air. Such findings prompt a reconsideration of glovebox-based perovskite solar cell research and establish a scenario where device fabrication can in fact greatly benefit from ambient oxygen.

Deep insights into the optoelectronic properties of AgCdF3-based perovskite solar cell using the combination of DFT and SCAPS-1D simulation

The main focus of this research is to explore the properties and photovoltaic application of AgCdF3, and hence, initially, the CASTEP software was used in this study to assess the structural, optical, mechanical, and electrical characteristics of the AgCdF3 perovskite absorber layer within the context of the density functional theory (DFT) method. AgCdF3 resulting from the structural research is confirmed to be chemically and thermodynamically stable by the estimated tolerance factor and formation enthalpy. According to the band structure analysis, AgCdF3 is an indirect band gap semiconductor with a band gap of 1.106 eV, where the electrons of Cd-4d and F-2s dominate the band edges of this semiconductor. Analysis of mechanical properties revealed that the AgCdF3 cubic perovskite has a stable structure and enhanced ductility, indicating superior machinability. After completing the DFT analysis, a one-dimensional solar cell capacitance simulator 1D (SCAPS-1D) was used with three popular electron transport layers (ETLs), including ZnO, PCBM, and C60, to examine the photovoltaic (PV) performance of various AgCdF3-based solar cell heterostructures. Based on simulation findings, the device design with ITO/ZnO/AgCdF3/CuI/Au showed the highest photoconversion efficiency compared to the other configurations. A detailed analysis was conducted for the aforementioned configurations to determine the impact of variations in the absorber and ETL thickness on PV performance. Moreover, the effects of the three designs were assessed in terms of function, generation and recombination rate, capacitance, operating temperature, series and shunt resistance, and Mott-Schottky. Thus, this comprehensive simulation with validation results demonstrated the true potential of AgCdF3 absorber with appropriate ETLs such as ZnO, PCBM, and C60; on the other hand, the CuI as hole transport layer (HTL), paving the way for promising studies to develop high-efficiency AgCdF3 PSCs for the photovoltaic industry.

Air-Processed All-Inorganic Halide Perovskites Integrated Photorechargeable Supercapacitors.

Due to their easy integration for self-powered operation, integrated energy harvesting and storage could be the game changer in smart, flexible, and portable electronic devices. Three-electrode integration is the most promising approach among all possible configurations because it is less complex and compatible with most techniques. Although the photoconversion efficiency has increased above 20% due to the integration of high-performance perovskite solar cells, the electrochemical storage efficiency (efficacy of the integration) is much below 80% due to a significant potential drop and impedance mismatch. In this context, we introduced perovskite-based solid-state thin film supercapacitors integrated with stable, air-processed perovskite solar cells for an uninterrupted power supply. Our measurement shows that the best performance can be achieved by optimizing several parameters, including series-connected solar cells, light intensity, and photovoltaic active area. The critical challenge with these integrated systems is to maintain a uniform charging current of the supercapacitors throughout the charging cycle while minimizing self-discharging. We achieved an electrochemical storage efficiency of ∼87% at an overpotential of 0.8 V. The overpotential can be as low as 2 mV. We fabricated fully solution-processed series-connected solar cells to integrate with stacked supercapacitors to improve the operating voltage beyond 2.1 V. The photocharging and dark discharging of these integrated devices have been tested over 200 cycles, and a negligible drop in efficiency has been observed. Our detailed energy conversion and storage analysis in these systems unveils the mechanism and losses due to three-terminal integration.