Improved Fill Factor Research Articles

Enhanced Charge and Energy Transfer in All-Small-Molecule Ternary Organic Solar Cells: Transient Photocurrent and Photovoltage and Transient Photoluminescence Measurements.

A donor-acceptor-donor (D-A-D) molecule, denoted asRC18, consistingoftwo nickel-porphyrinterminal donor units (D) and a selenophene-flanked diketopyrrolopyrrole central core, connected viaan ethynylene linker has been synthesized. The highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels were measured showing values of -5.49 eV and -3.75 eV, respectively. We have utilizedRC18as donor along with two acceptors, DICTF and Y6, for OSCs and found that power conversion efficiencies were 12.10% and 12.59% forRC18:DICTF andRC18:Y6, respectively. The complementary absorption profiles ofRC18, DICTF and Y6, along with the intermediate LUMO level of DICTF betweenRC18and Y6, led to the fabrication of ternary organic solar cells. RC18:DICTF:Y6 based ternary attainedpower conversion efficiency of 16.06%. The observed enhancement in the PCE is attributed to efficient exciton utilization through energy transfer from DICTF to Y6, increased donor-acceptor interfacial area, suppressed charge carrier recombination and improved molecular ordering. These all factors contributeto improvements in short-circuit current density (JSC) and fill factor (FF). Additionally, the open-circuit voltage (VOC) of the ternary OSC lies between those of the two binary OSCs indicating the formation of an alloy between the two acceptors.

Affordable excellence: unveiling the potential of graphitic carbon-based counter electrodes for high-performance dye-sensitized solar cells

Dye-Sensitized Solar Cells (DSSCs) have emerged as a promising alternative energy technology due to their minimal material requirements and straightforward production process, enabling efficient performance even under low-light conditions. Traditionally, high-performance DSSCs utilize platinum as the counter electrode. However, the high cost of platinum necessitates the development of more affordable counter electrodes that can match or surpass platinum-based counter electrodes (CEs) in conversion efficiency. This study investigates the synthesis and application of various cost-effective counter electrodes, including candle flame carbon soot, pencil lead graphite, and CS-coated PLG, in highefficiency DSSCs. For comparison, a platinum-based counter electrode is used as a benchmark. The working electrode comprises TiO2 on Fluorine-Doped Tin Oxide substrates. The DSSCs fabricated with counter electrodes such as PLG, CS, and CS-coated PLG exhibit efficiencies of approximately 6.2%, 3.5%, and 8.5%, respectively, compared to 10.8% for the Pt-based counter electrode. Reduced series resistance contributes to an improved Fill Factor and increased conversion efficiency. Furthermore, impedance spectroscopy reveals higher capacitance at the CE/electrolyte interface, enhancing charge collection efficiency and electron lifetime. Thus, the potential for significant improvement in conversion efficiency makes low-cost PLG and carbon-based electrodes a highly attractive alternative to Pt-based electrodes.

High Efficiency (>10%) AgBiS2 Colloidal Nanocrystal Solar Cells with Diketopyrrolopyrrole-Based Polymer Hole Transport Layer.

Silver bismuth disulfide (AgBiS2) colloidal nanocrystals (CNCs) have emerged as ecofriendly photoactive materials with excellent photoconductivity and high absorption coefficients, in compliance with the restriction of hazardous substances (RoHS) guidelines. To maximize the theoretical potential of AgBiS2 CNC solar cells, a new diketopyrrolopyrrole (DPP)-based polymer, BD2FCT, optimized as a hole transport layer (HTL), is developed. This asymmetric thiophene-rich polymer HTL effectively complements the optical absorption spectrum of CNCs and forms a homogeneous layer atop the CNCs, facilitating favorable vertical charge transfer through intrinsic molecular packing. Furthermore, the BD2FCT HTL aligns energetically with AgBiS2, significantly reducing charge recombination at the CNC/HTL interfaces and enhancing charge extraction and photocurrent generation across the entire optical absorption spectrum. These characteristics are further optimized through precise molecular engineering. Additionally, a low-bandgap acceptor, IEICO-4F, is structurally incorporated with the BD2FCT polymer to further improve charge funneling and complementary absorption. Transient absorption spectroscopy reveals enhanced hole transfer from CNC to BD2FCT-29DPP:IEICO-4F, resulting in reduced charge recombination and efficient charge extraction. Consequently, a BD2FCT-based AgBiS2 CNC solar cell achieves a power conversion efficiency (PCE) of 10.1%, demonstrating significant improvements in short-circuit current density (JSC) and fill factor (FF).

Enhancing hole-transport efficiency in (CH3NH3)2CuClxBr4-x perovskite solar cells through functionalization of multi-walled carbon nanotubes

This study addresses the conductivity limitation of conventional hole-transporting layers (HTLs) like Spiro-OMeTAD in perovskite solar cells. We integrate functionalized multi-walled carbon nanotubes (MWCNTs) into Spiro-OMeTAD and examine the impact of chemical oxidation/functionalization of MWCNTs on their application in perovskite solar cells. Various ratios of H2SO4/HNO3 mixture were employed to functionalize MWCNTs, with FTIR analysis confirming functional group attachments on the nanotube walls. Raman spectroscopy was utilized to analyze defect formation in the MWCNTs, while FESEM images displayed both the tubular structure and morphological alterations resulting from functionalization. XRD analysis was conducted to examine the structural variances resulting from different functionalization ratios. A lead-free copper-based perovskite (CH3NH3)2CuBr4-xClx (x = 0.5), synthesized via a straightforward solution method, served as the active material for solar cells. The XRD assessment of the active material confirmed perovskite formation, with morphological analysis revealing a layered structure. Diffuse Reflectance Spectroscopy (DRS) measurements yielded a bandgap of approximately 1.86 eV for the perovskite. Dark I–V measurements were executed for Spiro-OMeTAD films incorporated with pure and functionalized MWCNTs, showcasing improved conductivity attributed to charge carrier conduction via defect passivation. Hybrid solar cells were fabricated with structures such as TiO2/(CH3NH3)2CuBr4-xClx (x = 0.5)/Spiro-OMeTAD/Ag, and TiO2/(CH3NH3)2CuBr4-xClx (x = 0.5)/functionalized MWCNTs/Spiro-OMeTAD/Ag. These cells demonstrated enhanced stability, retaining over 65 % of their initial efficiency after 10 days of storage, attributed to improved moisture permeability inferred from contact angle measurements and XRD analysis. Photovoltaic characterization revealed significant improvements in fill factor (∼70 %), short-circuit current density (2.94 mA), open-circuit voltage (0.70 V), and power conversion efficiency (PCE) (1.6 %) for the FTO/TiO2/(CH3NH3)2CuCl0·5Br3.5/Spiro-MWCNT-1/Ag device.

MgAc2-Modified SnO2 Electron Transport Layer for Highly Efficient and Thermal Stable Perovskite Solar Cells.

There are always defects and oxygen vacancies in SnO2 prepared by solution methods, hindering efficient carrier transfer between SnO2 and the perovskite in perovskite solar cells. Thus, we employed MgAc2 to modify the interface. Carboxyl groups of MgAc2 filled the oxygen vacancies in SnO2, reducing its surface defect density, and Mg2+ partially replaced surface Sn4+, improving the properties of the SnO2 layer. Finally, perovskite solar cells modified with MgAc2 exhibited a significant improvement in open-circuit voltage and fill factor, improving the power conversion efficiency from 20.52% to 22.02%. Moreover, MgAc2-devices maintained 80% of the initial efficiency after 1250 h in thermal stability tests at 85 °C and 30% relative humidity compared to control devices. This work provides a method for treating the SnO2 electron transport layer and demonstrates the synergistic effects of Mg2+ and acetate ions, which can facilitate the development of efficient and stable perovskite solar cells.

Scalable fabrication approach and fill factor optimization for single pixel microlens arrays

Microlenses are a suitable approach to improve the performance of optical systems. An important optical efficiency determining parameter is the fill factor, which describes the relation of the lens area to the total optical active area. In this work, an optimization of the fill factor by optimizing the fabrication process steps is presented. The approach here is the use of i-line waferstepper lithography in combination with thermal reflow of photoresist and subsequent 1:1 pattern transfer in the lens material by reactive ion etching. For this method, the fill factor is determined by the minimum lens gap and, thus, the optical efficiency is strongly limited by the resolution limit of the i-line waferstepper lithography (350 nm). The goal of this investigation is to achieve the lowest possible lens gap even below the stepper-based resolution limit by optimizing each single process step without developing a new approach. The final result of the optimization was a fill factor improvement of 15%.

Molecularly tailored bifunctional nano-overlayers for efficient and stable inverted perovskite solar cells

Triple cation perovskite solar cells (PSCs) have made remarkable progress in power conversion efficiency (PCE), which is also related to the interface regulation layers between the active layer and electron transport layer (ETL). The ionic nature of the perovskite lattice has enabled approaches to passivate molecular defects through the interaction of functional groups. Herein, a passivator OXD-7 is introduced as a modified layer to passivate surface defects and accelerate electron transfer. It has been observed that OXD-7 can alleviate the micro-strain of the perovskite thin films through intermolecular bonding, which suppresses the iodide vacancy on the perovskite surface. Additionally, the OXD-7 reduces the surface energy of the perovskite films and inhibits the formation of δ-FAPbI3 on the surface of perovskite film. Consequently, the resulting devices demonstrate improved fill factor and device stability. Under optimal fabrication conditions, triple cation mixed perovskite solar cells with an inverted structure achieve a PCE of 23.83%.

Improved electrical contact properties in Indium-free silicon heterojunction solar cells with amorphous SnO2 TCO layers

Silicon heterojunction (SHJ) solar cells are recognized as one of the most efficient architectures in silicon-based photovoltaic devices. However, the reliance on indium (In)-based transparent conductive oxides (TCO) is anticipated to constrain their production capacity due to the critical and economically volatile nature of In. Recently, low-temperature-grown amorphous SnO2 (a-SnO2) films have been explored as an earth-abundant alternative TCO material. In this study, we examine the electrical contact properties of a-SnO2 layers employed as TCO layers in SHJ cells, focusing on their interaction with the underlying carrier selective contact layers. Our findings indicate that a stack of doped amorphous silicon (a-Si:H) and a-SnO2 exhibits relatively high specific contact resistivity, leading to a significant reduction in the device's fill factor. To address this issue, we propose two approaches: the insertion of a thin ZnO-based TCO layer between a-Si:H and a-SnO2, and the use of nanocrystalline silicon layers in place of a-Si:H. Both approaches effectively reduce the contact resistivity, resulting in improvements in fill factor and conversion efficiency comparable to those of benchmark device with In-based TCOs. Based on these findings, we demonstrate a high-efficiency, In-free, SnO2-based SHJ cell.

Multifaceted Design of Surface Passivator for Upgraded Charge Extraction in Perovskite Solar Cells

The nonradiative recombination arising from the interfaces of perovskite solar cells (PSCs) pose a hurdle, impacting both the efficiency and stability of devices. Functionalized organic molecules can passivate the perovskite surface to suppress the defects and can also fine‐tune the microstructure. This in turn promotes reliability and performance enhancement in solar cells. Using a design protocol, cyanoguanidine diiodide is synthesized and employed as a surface passivator for the fabrication of PSCs, and boosted performance from 20.44% to 23.04% is achieved. This improvement stems from an improved fill factor reaching up to 80.64%, together with the open‐circuit voltage (Voc) measuring 1119 mV. The steady‐state photoluminescence and microstructure of passivated perovskites display significant surface modification of the perovskite film which favorably impacts the charge carrier transfer at the interface of perovskite and Spiro‐OMeTAD. Our findings suggest that improved solar cell performance is due to the synergetic effect of amino and cyano functional groups along with the iodide reservoir in the organic passivator.

Se as hetero-nucleation seeds reinforcing intermetallic diffusion for improved electrodeposition-processed CZTS solar cells

Pure sulfide-based Cu2ZnSnS4(CZTS) stands as a competitive photovoltaic material, composted of earth-abundant, low-cost, and stable constituent elements. The stacked electrodeposition process has garnered attention owing to its facile regulation of elemental composition, and its non-vacuum, room-temperature, water-based solvent operating conditions. However, the limitation based on the stacked electrodeposition-processed CZTS primarily stems from the numerous defects and detrimental interfaces induced by the deficient intermetallic diffusion. Herein, a Se nanoparticle layer at the back interface is introduced to enhance the intermetallic diffusion, optimize the precursor morphology, and subsequently accelerate the grain growth. Comprehensive characterizations reveal Se, acting as the hetero-nucleation seeds, catalyzes Cu deposition and promotes a highly porous structure with a homogeneous elemental distribution. Consequently, high-quality CZTS with enhanced crystallinity and passivated defects is achieved, thereby promoting carrier transport and suppressing non-radiative recombination. These sequential positive effects result in a substantial improvement in short current density (Jsc) and fill factor (FF), attaining an improved efficiency. Our findings offer a promising strategy to overcome the issues of the stacked electrodeposition-processed films and highly contribute to the development of high-quality CZTS-based solar cells.

Quantifying the multifaceted influence of HTLs on the photovoltaic performance of inorganic Cs2TiBr6 solar cells: an OghmaNano numerical investigation

In this study, an environmentally friendly, stable Cs2TiBr6 perovskite solar cell (PSC) with two device configurations FTO/TiO2/Cs2TiBr6/Cu2O/Au and FTO/TiO2/Cs2TiBr6/MoO3/Au have been simulated using OghmaNano software. Two-hole transport layers (HTLs) have been used to do a comparative study. Cuprous Oxide (Cu2O) and Molybdenum Oxide (MoO3) are inorganic HTLs with bandgaps of 2.17 eV and 3 eV, respectively that are plentiful, non-toxic, and ideal for band matching. The study aims to optimize the PSCs performance by using inorganic MoO3 and Cu2O as HTL to replace the traditionally organic HTL. Key parameters like thickness, electron mobility, and recombination rate constant have been optimized to yield maximum efficiency. The outcomes show that Cu2O-HTL demonstrated superior performance with an optimal structure, resulting in a high efficiency of 21% and an improved fill factor (FF) of up to 86.52%. These findings suggest that Cs2TiBr6-based PSCs could significantly impact future photovoltaic research.

Undoped MoOX with oxygen-rich vacancies as hole transport material for efficient indoor/outdoor organic solar cells

Molybdenum oxide (MoOX) films are typically prepared using a thermally-evaporated MoO3 source (ev.MoO3) as the hole transport layer for inverted organic solar cells (OSCs). However, their low conductivity and interface element diffusion severely limit their efficiency and stability. Herein, a novel and effective thermal evaporation method of the MoO2 source to prepare undoped MoOX films with oxygen-rich vacancies and inhibitory atom diffusion properties electrode using ev.MoO2 as the source, is reported. Electron spin resonance analysis indicates that ev.MoO2 has a stronger oxygen vacancy signal peak than ev.MoO3, which contributes to its excellent conductivity. The inverted organic solar cells modified by ev.MoO2 yielded a significant improvement in short-circuit current density (JSC) and fill factor (FF). The power conversion efficiency (PCE) increased from 16.65 % in ev.MoO3 to 17.08 % in ev.MoO2 under AM 1.5 G, which is one of the highest values ever reported for inverted OSCs. Furthermore, owing to the high transmittance and low trap density, the PCE increased from 20.18 % with ev.MoO3 OSC to 22.13 % with ev.MoO2 OSC under 500 lux. In addition, scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy confirmed that ev.MoO2 can prevent the diffusion of Al from the electrode to the functional layers, resulting in a T80 exceeding 800 h under continuous illumination.

Achieving High Efficiency and Stability in Organic Photovoltaics with a Nanometer-Scale Twin p-i-n Structured Active Layer.

In pursuing high stability and power conversion efficiency for organic photovoltaics (OPVs), a sequential deposition (SD) approach to fabricate active layers with p-i-n structures (where p, i, and n represent the electron donor, mixed donor:acceptor, and electron acceptor regions, respectively, distinctively different from the bulk heterojunction (BHJ) structure) has emerged. Here, we present a novel approach that by incorporating two polymer donors, PBDBT-DTBT and PTQ-2F, and one small-molecule acceptor, BTP-3-EH-4Cl, into the active layer with sequential deposition, we formed a device with nanometer-scale twin p-i-n structured active layer. The twin p-i-n PBDBT-DTBT:PTQ-2F/BTP-3-EH-4Cl device involved first depositing a PBDBT-DTBT:PTQ-2F blend under layer and then a BTP-3-EH-4Cl top layer and exhibited an improved power conversion efficiency (PCE) value of 18.6%, as compared to the 16.4% for the control BHJ PBDBT-DTBT:PTQ-2F:BTP-3-EH-4Cl device or 16.6% for the single p-i-n PBDBT-DTBT/BTP-3-EH-4Cl device. The PCE enhancement resulted mainly from the twin p-i-n active layer's multiple nanoscale charge carrier pathways that contributed to an improved fill factor and faster photocurrent generation based on transient absorption studies. The PBDBT-DTBT:PTQ-2F/BTP-3-EH-4Cl film possessed a vertical twin p-i-n morphology that was revealed through secondary ion mass spectrometry and synchrotron grazing-incidence small-angle X-ray scattering analyses. The thermal stability (T80) at 85 °C of the twin p-i-n PBDBT-DTBT:PTQ-2F/BTP-3-EH-4Cl device surpassed that of the single p-i-n PBDBT-DTBT/BTP-3-EH-4Cl devices (906 vs 196 h). This approach of providing a twin p-i-n structure in the active layer can lead to substantial enhancements in both the PCE and stability of organic photovoltaics, laying a solid foundation for future commercialization of the organic photovoltaics technology.

Novel dual absorber configuration for eco-friendly perovskite solar cells: design, numerical investigations and performance of ITO-C60-MASnI3-RbGeI3-Cu2O-Au

Perovskite solar cells (PSCs) are increasingly being used as the foundation of the worldwide photovoltaic (PV) industry because of their cost-effective production and durable stability. Perovskite materials, both organic and inorganic, possess distinct optical, mechanical, and electrical properties, such as a high absorption coefficient, a customizable band gap, and a synthesis method based on solutions. This study employed numerical investigations to devise and propose innovative solar cell configurations utilizing the SCAPS-1D simulator. This research presents a Perovskite solar cell design comprising an ITO-C60-MASnI3-RbGeI3-Cu2O-Au solar cell configuration. The unique arrangement of this setup incorporates the use of Indium Tin-oxide (ITO) as the upper contact layer, which is directly exposed to light. The electron transport layer (ETL) is composed of a 0.030 μm thick layer of C60, while the light-harvesting/absorber layers are made up of MASnI3 and RbGeI3, each with a thickness of 0.4 µm. A layer of Cu2O with a thickness of 0.12 μm is employed as the hole transport layer (HTL), whereas the back-contact layer consists of Au. A comparison research was conducted to examine the optimal device configuration. Comprehensive studies are performed to assess the effects of different variables on optimized device performance and power conversion efficiency (PCE). These factors include interface defect densities, thicknesses of different structural layers, band gaps, series and shunt resistance, and operational temperature. The current density (Jsc) is calculated as 32.7 mA/cm2 at an open circuit voltage (Voc) of 0.914 V. Additionally, we observed a power conservation efficiency (PCE) of 20.19 % and an improved fill factor (FF) value of 65.49 %. The ongoing investigations are likely to be valuable for the development and production of cost-effective and high-performance PSCs.

High-Performance PM6:Y6-Based Ternary Solar Cells with Enhanced Open Circuit Voltage and Balanced Mobilities via Doping a Wide-Band-Gap Amorphous Acceptor.

Great progress has been made in organic solar cells (OSCs) in recent years, especially after the report of the highly efficient small-molecule electron acceptor Y6. However, the relatively low open circuit voltage (VOC) and unbalanced charge mobilities remain two issues that need to be resolved for further improvement in the performance of OSCs. Herein, a wide-band-gap amorphous acceptor IO-4Cl, which possessed a shallower lowest unoccupied molecular orbital (LUMO) energy level than Y6, was introduced into the PM6:Y6 binary system to construct a ternary device. The mechanism study revealed that the introduced IO-4Cl was alloyed with Y6 to prevent the overaggregation of Y6 and offer dual channels for effective hole transportation, resulting in balanced hole and electron mobilities. Taking these advantages, an enhanced VOC of 0.894 V and an improved fill factor of 75.58% were achieved in the optimized PM6:Y6:IO-4Cl-based ternary device, yielding a promising power conversion efficiency (PCE) of 17.49%, which surpassed the 16.72% efficiency of the PM6:Y6 binary device. This work provides an alternative solution to balance the charge mobilities of PM6:Y6-based devices by incorporating an amorphous high-performance LUMO A-D-A small molecule as the third compound.

Additive-Assisted Hydrothermal Growth Enabling Defect Passivation and Void Remedy in Antimony Selenosulfide Solar Cells.

Antimony selenosulfide (Sb2(S,Se)3) has recently emerged as a promising light-absorbing material, attributed to its tunable photovoltaic properties, low toxicity, and robust environmental stability. However, despite these advantages, the current record efficiency for Sb2(S,Se)3 solar cells significantly lags behind their Shockley-Queisser limit, especially when compared to other well-established chalcogenide-based thin-film solar cells, such as CdTe and Cu(In,Ga)Se2. This underperformance primarily arises from the formation of unfavorable defects, predominately located at deep energy levels, which act as recombination centers, thereby limiting the potential for performance enhancement in Sb2(S,Se)3 solar cells. Specifically, deep-level defects, such as sulfur vacancy (VS), have a lower formation energy, leading to severe non-radiative recombination and compromising device performance. To address this challenge, thioacetamide (TA), a sulfur-containing additive is introduced, into the precursor solution for the hydrothermal deposition of Sb2(S,Se)3. This results indicate that the incorporation of TA helps in passivating deep-level defects such as sulfur vacancies and in suppressing the formation of large voids within the Sb2(S,Se)3 absorber. Consequently, Sb2(S,Se)3 solar cells, with reduced carrier recombination and improved film quality, achieved a power conversion efficiency of 9.04%, with notable improvements in open-circuit voltage and fill factor. This work provides deeper insights into the passivation of deep-level donor-like VS defects through the incorporation of a sulfur-containing additive, highlighting pathways to enhance the photovoltaic performance of Sb2(S,Se)3 solar cells.

Interfacial engineering with a ferrocene derivative for air-stable inverted perovskite solar cells with high fill factor of 83.57 %

Perovskite solar cells have demonstrated exceptional photovoltaic performance, but stability remains a challenge due to insufficient interfaces. In this work, a UV-resistance ferrocene derivative, 1,1′-bis (diphenylphosphine) ferrocene (DPPF), is introduced between the electron transport layer and the perovskite, reducing defect density by interaction with undercoordinated Pb2+, suppressing non-radiative recombination of charge carriers, and enhancing electron extraction. Desirable interfacial properties and homogeneous perovskite grains are formed, resulting in a champion power conversion efficiency (PCE) of 20.82 % and a significantly improved fill factor of 83.57 %. Moreover, DPPF can optimize the interfaces, provide a brand-new morphology with exceptional air durability, cover the active layer to restrain water and oxygen intrusion, and suppress metal electrode corrosion. Resultant devices without encapsulation have remained above 80 % of their initial PCE for 1400 h under 25 °C air and 50–60 % relative humidity conditions.

A numerical approach to optimize the efficiency of a novel HTL-free Sr3Ti2S7 Ruddlesden-Popper perovskite solar cell

The exceptional environmental and structural stability of two-dimensional Ruddlesden-Popper perovskites has made them appealing candidates for high-performance perovskite solar cells. Besides, Ruddlesden-Popper perovskites can be synthesized using low-cost solution processing and have tunable bandgaps as compared to their conventional three-dimensional counterparts. Therefore, a Ruddlesden–Popper perovskite solar cell has been reported in this investigation and the SCAPS program has been used to theoretically study the device performance of the proposed lead-free, environmentally friendly perovskite solar cell. A novel Sr3Ti2S7 material has been utilized as the light absorber for the first time in such a theoretical study. Two different configurations, employing WS2 and C60 electron transport layers have been presented and device simulations have been performed to optimize the solar cell. The utilization of C60 as an electron transport material did not prove to be beneficial for the solar cell as it suffered from major recombination losses. It was also found that higher doping concentration of the electron transport materials could help these cells achieve improved fill factor. The diffusion length of the electrons and holes with respect to absorber defect density was also determined. Mott-Schottky analysis proved that the ITO/C60/Sr3Ti2S7/Au structure had a lower flatband potential compared to ITO/WS2/Sr3Ti2S7/Au. Additionally, from the impedance spectroscopy results, the recombination lifetime of the ITO/WS2/Sr3Ti2S7/Au configuration was found to be 46.7 μs compared to only 12.9 μs for the ITO/C60/Sr3Ti2S7/Au architecture. It was also established that if the thickness of the absorber and the bulk defect concentration were optimized the ITO/WS2/Sr3Ti2S7/Au and ITO/C60/Sr3Ti2S7/Au solar cells could achieve conversion efficiencies close to 11.0 % and 10.0 % respectively.

Suppressing Deep-Level Trap Toward Over 13% Efficient Solution-Processed Kesterite Solar Cell.

Cu2ZnSn (S,Se)4 (CZTSSe), a promising absorption material for thin-film solar cells, still falls short of reaching the balance limit efficiency due to the presence of various defects and high defect concentration in the thin film. During the high-temperature selenization process of CZTSSe, the diffusion of various elements and chemical reactions significantly influence defect formation. In this study, a NaOH-Se intermediate layer introduced at the back interface can optimize Cu2ZnSnS4 (CZTS)precursor films and subsequently adjust the Se and alkali metal content to favor grain growth during selenization. Through this back interface engineering, issues such as non-uniform grain arrangement on the surface, voids in bulk regions, and poor contact at the back interface of absorber layers are effectively addressed. This method not only optimizes morphology but also suppresses deep-level defect formation, thereby promoting carrier transport at both interfaces and bulk regions of the absorber layer. Consequently, CZTSSe devices with a NaOH-Se intermediate layer improved fill factor, open-circuit voltage, and efficiency by 13.3%. This work initiates from precursor thin films via back interface engineering to fabricate high-quality absorber layers while advancing the understanding regarding the role played by intermediate layers at the back interface of kesterite solar cells.

[Ce3+-Pr3+-Nd3+]:CsPbI2.2Br0.8 stable energy system for photonic and electrical performance upgradation in multitudinous applications

Adopting an integrated and consolidated strategy to energy generation, conversion, and storage is linked to energy sustainability in the modern day. Current investigation explores the lanthanide triple doping mechanism coupled with temperature optimization using (cerium, praseodymium, and neodymium)-oxide to modify CsPbI2.2Br0.8 forming the stable [Ce3+-Pr3+-Nd3+]:CsPbI2.2Br0.8 (CPN:CPVSK) hetero-system. CPN:CPVSK thin films have remarkable optical output for the prolonged duration of 28 days with the band gap energy spanning around 1.64–1.67 eV. These thin films have cubic phase with the 65.44 nm average crystallite size and these thin films have excellent surficial binding without any holes or cracks. CPN:CPVSK was employed as an active light trapping material inside perovskite solar cells processed and analyzed at ambient conditions. The temperature increment from 100 to 200 °C subsequently lead to improvement in efficiency from 6.91% to 15.5% with considerable improvement in fill factor. CPN:CPVSK effectively generated pure H2 with the minor overpotential and Tafel slope values of 132 mV and 122.3 mV dec−1 while the O2 production activity was unappreciable. CPN:CPVSK is a potential material for battery application with the excellent unit capacity of 354 mA H g−1 and lower Rs of 0.44 Ω. Rare earth doped perovskite material is a sustainable, cost effective, and facile to prepare with the greater candidature for practical applications.