Search Results (83)

The advancement of efficient and stable perovskite solar cells (PSCs) increasingly depends on developing flexible, metal-free electrode architectures. Single-walled carbon nanotubes (SWCNTs) offer chemical robustness, high conductivity, and mechanical flexibility, making them promising candidates to replace brittle metal cathodes. However, pristine SWCNTs are intrinsically p-type, creating energy barriers and recombination losses in inverted (p–i–n) PSCs. Achieving stable n-type doping compatible with both SWCNTs and perovskites is therefore critical. Here, seven representative n-type dopants, small molecules (TBD and TPP), ionic salts (TBAI, TBABr, and B18C6·KCl), and polymers (PEI and PVP) were systematically investigated to elucidate their effects on doping efficiency and interfacial stability. Morphological, structural, and electronic analyses supported by DFT calculations reveal that strong bases and ionic dopants promote perovskite degradation, whereas polymeric and coordination-type dopants preserve crystallinity and surface uniformity. Among them, PEI- and TPP-doped SWCNT electrodes achieved the best device performance, with power conversion efficiencies of 9.6% and 8.1%, respectively, demonstrating efficient electron extraction and interfacial stability. These findings highlight that interfacial chemical compatibility rather than intrinsic donor strength governs the effectiveness of n-type SWCNT doping, providing rational design principles for stable, metal-free perovskite photovoltaics. Full article

Perovskite solar cells (PSCs) have achieved remarkable efficiencies, yet further progress is limited by defect-induced nonradiative recombination and instability associated with uncontrolled crystallization. Here, we develop a protic ionic-liquid precursor engineering strategy based on methylammonium acetate (MAAc) for high-performance inverted (p–i–n) triple-cation perovskite solar cells. Systematic variation of the MAAc content reveals that a moderate concentration yields perovskite films with enlarged grains, suppressed pinholes, and strongly reduced residual PbI₂. Steady-state and time-resolved photoluminescence measurements, together with electrochemical impedance spectroscopy and light-intensity-dependent analysis, demonstrate that MAAc effectively suppresses trap-assisted nonradiative recombination, prolongs carrier lifetime, and increases recombination resistance without introducing additional transport losses. As a result, optimized inverted devices deliver a champion power conversion efficiency of 23.68% with a high open-circuit voltage of 1.21 V, a fill factor of ~0.83, negligible J–V hysteresis, and excellent device-to-device reproducibility. Moreover, the MAAc-2M devices exhibit markedly improved operational and shelf stability, retaining 73.2% of their initial efficiency after 30 days, compared to 53.2% for the control. This work establishes MAAc as an effective ionic-liquid additive that simultaneously governs crystallization and defect chemistry, offering a general route to efficient and stable inverted perovskite solar cells via protic ionic-liquid-assisted precursor engineering. Full article

Lead halide-based perovskite solar cells have gained significant attention from academia and the photovoltaic industry due to their exceptional optical and electrical characteristics. The primary problem with Pb-based perovskite pertains to its toxicity and solubility in water within the external environment. These concerns regarding hazards to the environment are constraining the application of lead-based perovskite in both consumer and industrial contexts. To offer a viable alternative to lead-based hazardous perovskite solar cells, we examined an inverted (p-i-n) perovskite structure with three distinct absorber layers based on cesium bismuth halides (Cs₃Bi₂I₉, Cs₃Bi₂Cl₉, Cs₃Bi₂Br₉) and conducted a comparative analysis utilizing SCAPS-1D software (version 3.3.08). The comparison analysis of our design against starting parameters indicated that the optimal power conversion efficiency (PCE) of 10.01% was recorded for Cs₃Bi₂I₉, 7.56% for Cs₃Bi₂Br₉, and 4.34% for Cs₃Bi₂Cl₉. Following careful optimization of the thickness of charge-transport layers (CTLs), doping concentrations of CTLs, and all three absorber layers, the overall efficiencies of the three inverted structures were enhanced from 10.01% to 14.08% for Cs₃Bi₂I₉, from 4.34% to 5.28% for Cs3Bi2Cl9, and from 7.56% to 11.05% for Cs₃Bi₂Br₉, respectively. The other performance enhancement, open-circuit voltage, increased from 1.08 V to 1.37 V for Cs₃Bi₂I₉, from 1.26 V to 1.47 V for Cs₃Bi₂Cl₉, and from 1.20 V to 1.47 V for Cs₃Bi₂Br₉. This comparative analysis of proposed perovskite devices demonstrates that Cs₃Bi₂X-based perovskite devices possess significant potential to replace conventional hazardous solar cells in the renewable and clean energy sectors. Full article

In this study, p-type NiO_x and Cu-doped NiO_x nanoparticles (NPs) were synthesized by a simple chemical precipitation method and used as hole transport layers (HTLs) for inverted perovskite solar cells (PSCs). The microstructural property, surface morphology, elemental composition, optical property, charge recombination, and surface topography of the NiO_x and Cu-NiO_x HTLs were comprehensively characterized. The results showed that the NiO_x and Cu-NiO_x NPs were uniformly coated on the substrates without pinholes or voids. Cu incorporation into NiO_x did not change its crystalline nature and considerably improved its electrical conductivity. The Cu-NiO_x HTLs exhibited superior photoluminescence quenching and the least lifetime decay, which indicated that Cu-NiO_x exhibited higher charge transport than NiO_x HTLs. The fabricated PSC performances were further analyzed using current density–voltage characteristics, external quantum efficiency, and electrochemical impedance spectroscopy. The PSCs with PEDOT:PSS, NiO_x, and 2% Cu-NiO_x HTLs exhibited power conversion efficiencies of 11.93%, 13.72%, and 15.54%, respectively. The 2% Cu-NiO_x HTL-based device showed the best performance compared with the PEDOT:PSS- and NiO_x-based devices. Academic Editors: Chunyang Zhang, Dou Zhang Full article

Inverted (p-i-n) CsPbI_xBr_3−x (x = 0~3) perovskite solar cells (PSCs) are of growing interest due to their excellent thermal stability and optoelectronic performance. However, they suffer from severe energy level mismatch and significant interfacial energy losses at the bottom hole transport layers (HTLs). Herein, we propose a strategy to simultaneously enhance the crystallinity of CsPbI_2.85Br_0.15 and facilitate hole extraction at the HTL/CsPbI_2.85Br_0.15 interface by incorporating semiconducting single-walled carbon nanotubes (SWCNTs) onto [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl] phosphonic acid (MeO-2PACz) HTL. The unique electrical properties of SWCNTs enable the MeO-2PACz/SWCNT HTL to achieve high conductivity, optimal energy level alignment, and an adaptable surface. Consequently, the defect density is reduced, hole extraction is accelerated, and interfacial charge recombination is effectively suppressed. As a result, these synergistic benefits boost the power conversion efficiency (PCE) from 15.74% to 18.78%. Moreover, unencapsulated devices retained 92.35% of their initial PCE after 150 h of storage in ambient air and 89.03% after accelerated aging at 85 °C for 10 h. These findings highlight the strong potential of SWCNTs as an effective interlayer for inverted CsPbI_2.85Br_0.15 PSCs and provide a promising strategy for designing high-performance HTLs by integrating SWCNTs with self-assembled monolayers (SAMs). Full article

Metal halide perovskites have appeared as a promising semiconductor for high-efficiency and low-cost photovoltaic technologies. However, their performance and long-term stability are dramatically constrained by defects at the surface and grain boundaries of polycrystalline perovskite films formed during the processing. Herein, we propose a defect-targeted passivation strategy using 2-chlorocinnamic acid (2-Cl) to simultaneously enhance the efficiency and stability of perovskite solar cells (PSCs). The crystallization kinetics, film morphology, and optical and electronic properties of the used formamidinium–cesium lead halide (FA_0.85Cs_0.15Pb(I_0.95Br_0.05)₃, FACs) absorber were modulated and systematically investigated by various characterizations. Mechanistically, the carbonyl group in 2-Cl coordinates with undercoordinated Pb²⁺ ions, while the chlorine atom forms Pb–Cl bonds, effectively passivating the surface and interfacial defects. The optimized FACs perovskite film was incorporated into inverted (p-i-n) PSCs with a typical architecture of ITO/NiO_x/PTAA/Al₂O₃/FACs/PEAI/PCBM/BCP/Ag. The optimal device delivers a champion power conversion efficiency (PCE) of 22.58% with an open-circuit voltage of 1.14 V and a fill factor of 82.8%. Furthermore, the unencapsulated devices retain 90% of their initial efficiency after storage in ambient air for 30 days and 83% of their original PCE after stress under 1 sun illumination with maximum power point tracking at 50 °C in a N₂ environment, demonstrating the practical potential of dual-site molecular passivation for durable perovskite photovoltaics. Full article

Poly[bis(4-phenyl) (2,5,6-trimethylphenyl) amine (PTAA), as a hole transfer material, has been widely used in perovskite solar cells (PSCs). However, the optimal solvent for preparing the PTAA solution and coating the PTAA layer is still uncertain. In this work, we investigated three types of organic solvents (toluene, chlorobenzene and dichlorobenzene) for processing PTAA layers as the hole transport layer in PSCs. Based on the experimental verification and molecular dynamics simulation results, all the evidence indicated that toluene performs best among the three candidates. This is attributed to the significant polarity difference between toluene and PTAA, which leads to the formation of a uniform surface morphology characterized by granular protuberances after spin coating. The contact area of the hole transfer layer with the surface aggregation is increased in reference to the rough surface, and the hydrophilicity of the PTAA layer is also increased. The improvement of these two aspects are conducive to the effective interfacial charge transfer. This leads to the generation of more photocurrent. The PSCs employing toluene-processed PTAA exhibit an average power conversion efficiency (PCE) of 19.1%, which is higher than that of PSCs using chlorobenzene- and dichlorobenzene-processed PTAA (17.3–17.9%). This work provides a direct optimization strategy for researchers aiming to fabricate PSCs based on PTAA as a hole transport layer and lays a solid foundation for the development of high-efficiency inverted PSCs. Full article

This work explored an electrochemical approach for synthesizing lanthanum-modified nickel oxide (NiO_x:La) as a hole transport layer (HTL) in inverted perovskite solar cells (IPSCs). By varying the La³⁺ concentration, the chemical, charge transport, structural, and morphological properties of the NiO_x:La film and the HTL/PVK interface were evaluated to enhance photovoltaic performance. X-ray photoelectron spectroscopy (XPS) confirmed La³⁺ incorporation, a higher Ni³⁺/Ni³⁺ ratio, and a valence band shift, improving p-type conductivity. Electrochemical impedance spectroscopy and Mott–Schottky analyses indicated that NiO_x:La 0.5% exhibited the lowest resistance and the highest carrier density, correlating with higher recombination resistance. The NiO_x:La 0.5% based cell achieved a PCE of 20.08%. XRD and SEM confirmed no significant changes in PVK structure, while photoluminescence extinction demonstrated improved charge extraction. After 50 days, this cell retained 80% of its initial PCE, whereas a pristine NiO_x device retained 75%. Hyperspectral imaging revealed lower optical absorption loss and better homogeneity. These results highlight NiO_x:La as a promising HTL for efficient and stable IPSCs. Full article

In recent years, inverted perovskite solar cells (PSCs) have garnered widespread attention due to their high compatibility, excellent stability, and potential for low-temperature manufacturing. However, most of the current research has primarily focused on the surface passivation of perovskite. In contrast, the buried interface significantly influences the crystal growth quality of perovskite, but it is difficult to effectively control, leading to relatively slow research progress. To address the issue of poor interfacial contact between the hole transport-layer nickel oxide (NiOX) and the perovskite, we introduced a conjugated self-assembled monolayer (SAM), 4,4′-[(4-(3,6-dimethoxy-9H-carbazole)triphenylamine)]diphenylacetic acid (XS21), which features triphenylamine dicarboxylate groups. For comparison, we also employed the widely studied phosphonic acid-based SAM, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl] phosphonic acid (MeO-2PACz). A systematic investigation was carried out to evaluate the influence of these SAMs on the performance and stability of inverted PSCs. The results show that both XS21 and MeO-2PACz significantly enhanced the crystallinity of the perovskite layer, reduced defect densities, and suppressed non-radiative recombination. These improvements led to more efficient hole extraction and transport at the buried interface. Consequently, inverted PSCs incorporating XS21 and MeO-2PACz achieved impressive power-conversion efficiencies (PCEs) of 21.43% and 22.43%, respectively, along with marked enhancements in operational stability. Full article

Despite the rapid efficiency advancement of perovskite solar cells (PSCs), non-radiative recombination at the buried interface between self-assembled monolayers (SAMs) and perovskite remains a critical bottleneck, primarily due to interfacial defects and energy level mismatch. In this study, we demonstrate a bifunctional interlayer engineering strategy by introducing 4,5-diiodoimidazole (4,5-Di-I) at the Me-4PACz/perovskite interface. This approach uniquely addresses two fundamental limitations of SAM-based interfaces: the insufficient defect passivation capability of conventional Me-4PACz due to steric hindrance effects and the poor perovskite wettability on hydrophobic SAM surfaces that exacerbates interfacial voids. The imidazole derivatives not only form strong Pb–N coordination bonds with undercoordinated Pb²⁺ but also modulate the surface energy of Me-4PACz, enabling the growth of pinhole-free perovskite films with preferential crystal orientation. The champion device with 4,5-Di-I modification achieves a power conversion efficiency (PCE) of 24.10%, with a V_OC enhancement from 1.12 V to 1.14 V, while maintaining 91% of initial PCE after 1300 h in N₂ atmosphere (25 °C), demonstrating superior stability under ISOS-L-2 protocols. This work establishes a universal strategy for interfacial multifunctionality design, proving that simultaneous defect suppression and crystallization control can break the long-standing trade-off between efficiency and stability in solution-processed photovoltaics. Full article

The hole-transport layer (HTL) plays a pivotal role in engineering high-performance inverted perovskite solar cells (PSCs), as it governs both hole extraction/transport dynamics and critically impacts the crystallization quality of the perovskite absorber layer in device architectures. Recent advancements have highlighted self-assembled monolayers (SAMs) as promising candidates for next-generation HTL materials in inverted PSCs due to their intrinsic advantages over conventional counterparts. These molecularly engineered interfaces demonstrate superior characteristics including simplified purification processes, tunable molecular structures, and enhanced interfacial compatibility with device substrates. This review systematically examines the progress, existing challenges, and future prospects of SAM-based HTLs in inverted photovoltaic systems, aiming to establish a systematic framework for understanding their structure–property relationships. The review is organized into three sections: (1) fundamental architecture of inverted PSCs, (2) molecular design principles of SAMs with emphasis on head-group functionality, and (3) recent breakthroughs in SAM-engineered HTLs and their modification strategies for HTL optimization. Through critical analysis of performance benchmarks and interfacial engineering approaches, we elucidate both the technological merits and inherent limitations of SAM implementation in photovoltaic devices. Furthermore, we propose strategic directions for advancing SAM-based HTL development, focusing on molecular customization and interfacial engineering to achieve device efficiency and stability targets. This comprehensive work aims to establish a knowledge platform for accelerating the rational design of SAM-modified interfaces in next-generation optoelectronic devices. Full article

Solution processing represents a widely adopted methodology for perovskite solar cell (PSC) fabrication. Nevertheless, the prevalent use of toxic solvents and anti-solvents in conventional approaches presents significant challenges for PSC commercialization. Water, as an environmentally benign solvent with exceptional Pb(NO₃)₂ solubility, offers a promising alternative for perovskite film preparation. However, the sluggish conversion kinetics of Pb(NO₃)₂ to perovskite often results in morphological imperfections and incomplete conversion, particularly detrimental to planar inverted PSCs derived from aqueous solutions, which currently exhibit limited power conversion efficiencies (PCE) of approximately 6%. To mitigate the Ostwald ripening effect induced by slow reaction kinetics and enhance the conversion efficiency of deep-layer Pb(NO₃)₂ and PbI₂, this study proposes a strategy of increasing the pore size in porous Pb(NO₃)₂ structures. Through the incorporation of sodium dodecyl sulfonate (SDS) surfactant into the Pb(NO₃)₂ precursor solution, we successfully fabricated high-quality perovskite films. Comprehensive characterization revealed that SDS doping effectively modified the surface properties of Pb(NO₃)₂ films, accelerating their conversion to perovskite. The optimized PSCs based on SDS-modified perovskite films demonstrated improved energy level alignment, enhanced charge carrier extraction, and suppressed non-radiative recombination. Consequently, the PCE of planar inverted aqueous PSCs increased significantly from 12.27% (control devices) to 14.82% following surfactant modification. After being stored in a nitrogen glove box for 800 h, the performance of the device still remained above 90% of its original level. It can still maintain 60% of its original performance after a 100 h heating aging test at 80 degrees. Full article

To meet the demands for functional layers in inverted flexible perovskite solar cells, high-performance formamidinium-based perovskite solar cells, and high-performance photodetectors in future applications, it is crucial to appropriately reduce the bandgap of third-generation wide-bandgap semiconductor materials. In this study, we first optimized doping sites through Ag-Cl and Ag-S configurations to establish stable substitution patterns, followed by density functional theory (DFT) calculations using the Generalized Gradient Approximation with the Perdew–Burke–Ernzerhof (GGA-PBE) functional, implemented in the Vienna Ab initio Simulation Package (VASP). A plane-wave basis set with a cutoff energy of 450 eV and a 3 × 4 × 3 Γ-centered k-mesh were adopted to investigate the effects of Mg-Cl, Mg-S, Zn-Cl, and Zn-S co-doping on the structural stability, electronic properties, and optical characteristics of β-Ga₂O₃. Based on structural symmetry, six doping sites were considered, with Ag-S/Cl systems revealing preferential occupation at octahedral Ga(1) sites through site formation energy analysis. The results demonstrate that Mg-Cl, Mg-S, Zn-Cl, and Zn-S co-doped systems exhibit thermodynamic stability. The bandgap of pristine β-Ga₂O₃ was calculated to be 2.08 eV. Notably, Zn-Cl co-doping achieves the lowest bandgap reduction to 1.81 eV. Importantly, all co-doping configurations, including Mg-Cl, Mg-S, Zn-Cl, and Zn-S, effectively reduce the bandgap of β-Ga₂O₃. Furthermore, the co-doped systems show enhanced visible light absorption (30% increase at 500 nm) and improved optical storage performance compared to the pristine material. Full article

The interface between nickel oxide (NiO_x) and self-assembled monolayers (SAMs) in perovskite solar cells (PSCs) often suffers from limited adsorption strength, poor energy-level alignment, and inadequate defect passivation, which hinder device performance and stability. To address these issues, we introduce a hybrid hole selective layer (HSL) combining atomic layer deposition (ALD)-fabricated NiO_x with full-aromatic SAM molecules, creating a highly stable and efficient interface. ALD NiO_x, enriched with hydroxyl groups, provides robust adsorption sites for the SAM molecule MeO-PhPACz, ensuring a strong, stable interaction. This hybrid HSL enhances energy-level alignment, hole selectivity, and defect passivation at the NiO_x/perovskite interface. Devices utilizing this approach demonstrate significant performance improvements, achieving a power conversion efficiency (PCE) of 21.74%, with reduced voltage losses and minimal hysteresis. Furthermore, operational stability tests reveal enhanced durability under elevated humidity and temperature conditions. These findings highlight the potential of ALD NiO_x and SAM hybrid HSL to overcome existing barriers, advancing the commercial viability of PSC technologies. Full article

The interest in alternative energy sources, including the use of solar radiation energy, is growing year by year. Currently, the most frequently installed photovoltaic modules are made of single-crystalline silicon solar cells (sc-Si). However, one of the latest solutions are perovskite solar cells (PSC), which are considered the future of photovoltaics. Therefore, the main objective of this research was to assess the environmental impact of the construction materials of monocrystalline and perovskite photovoltaic power plants toward their sustainable development. The research object was the construction materials and components of two 1 MW photovoltaic power plants: one based on monocrystalline modules and the other on perovskite modules. The life cycle assessment (LCA) method was used for the analyses. The IMPACT World+, IPCC and CED models were used in it. The analyses were performed separately for five sets of elements: support structures, photovoltaic panels, inverter stations, electrical installations and transformers. Two post-consumer management scenarios were adopted: storage and recycling. The life cycle of a photovoltaic power plant based on photovoltaic modules made of perovskite cells is characterized by a smaller negative impact on the environment compared to traditional power plants with monocrystalline silicon modules. Perovskites, as a construction material of photovoltaic modules, fit better into the main assumptions of sustainable development compared to cells made of monocrystalline silicon. However, it is necessary to conduct further work which aims at reducing energy and material consumption in the life cycles of photovoltaic power plants. Full article