Perovskite Research Articles (Page 1)

Lead iodide crystal arrangement modulation promotes preferential growth of perovskite orientation for efficient and stable solar cells.

The rapid expansion of the Internet of Things (IoT) has intensified the demand for durable, self-powered systems that can simultaneously harvest energy and sense environmental stimuli. Triboelectric nanogenerators (TENGs) have gained significant attention for their versatility in harnessing various environmental energy sources. However, conventional TENGs suffer from interfacial wear and lack photoresponsiveness, limiting their wide applicability. We report a photoenhanced, noncontact TENG based on quasi-2D perovskite (PVK) that combines robust stability and modulated output performance under light illumination. The vertically oriented quasi-2D PVK architecture facilitates balanced carrier mobility, enabling efficient charge generation, transport, and accumulation. Operated in a noncontact configuration, the device eliminates mechanical degradation, maintaining structural and functional integrity under thermal stress at 80 °C and prolonged operation. Under illumination, light-mediated electrification boosts output by 75%, validating the synergistic interaction between optical and mechanical inputs. The device further functions as a self-powered sensor, capable of detecting both regular and irregular motions with enhanced sensitivity under light. This design strategy overcomes the durability-efficiency trade-off that has long constrained TENG development and establishes quasi-2D PVKs as a promising platform for resilient, self-powered systems. These findings open new pathways for adaptive energy harvesting and integrated sensing for the future connected society.

Comprehensive Summary Perovskite solar cells (PSCs) are promising thin‐film photovoltaic devices and achieve a high power conversion efficiency (PCE) of 27.3% (certified). Hole transport layer (HTL) composed of nickel oxide (NiO x ) and [4‐(3,6‐dimethyl‐9 H ‐carbazol‐9‐yl)butyl]phosphonic acid (Me‐4PACz) is extensively utilized in these devices. However, the dispersion and conductivity of NiO x are suboptimal, and it exhibits energy‐level mismatch. Meanwhile, the coverage of Me‐4PACz on NiO x is non‐uniform. Herein, we synthesized magnesium ion‐doped nickel oxide (Mg:NiO x ) with more surface hydroxyl groups to address these issues. More surface hydroxyl groups provided more binding sites for Me‐4PACz, resulting in a denser and more uniform coverage of Me‐4PACz. Consequently, fewer defects were present at the buried interface, and a better environment for the crystallization of perovskite (PVK) was established. Furthermore, Mg:NiO x /Me‐4PACz enabled better energy level alignment with PVK. The Mg:NiO x ‐based PSCs achieved a champion PCE of 25.86%, representing a notable improvement over the NiO x ‐based devices (24.51%). After 462 h of continuous illumination testing, the PSCs with Mg:NiO x retained 96.8% of their initial PCE, while those with NiO x only maintained 62.9% of their initial PCE. Thus, Mg:NiO x effectively enhanced both the PCE and stability of PSCs.

Carbon- electrode (CE) based, hole-conductor-free mesoscopic perovskite solar cells (meso-CPSCs) offer the merits of high stability and low cost, but they contain a large number of nanosized perovskite (PVSK) crystallites in the CE region. These crystallites contribute little to light absorption, but bring risks of charge recombination. Herein, a three-step holistic treatment is introduced to address this issue, such as treatment-1 (T1): partial CE peeling; treatment-2 (T2): octylammonium iodide modification; and treatment-3 (T3): coating of a secondary layer of CE. Low-temperature meso-CPSCs are chosen as the model platform to perform the strategy. It is observed that the strategy removes the redundant PVSK crystallites, induces the formation of tilt-stacked two-dimensional(2D) PVSK, and strengthens interfacial contact of PVSK/CE, which reduces the recombination risks and facilitates interfacial charge-extraction, and finally elevates the power conversion efficiency (PCE) of the low-temperature meso-CPSCs from 14.25(±0.69)% to 16.05(±0.40)%(optimized to 17.28%). The efficiency is furtherupgradedto 18.07% after additional optimization on internal resistance and substrate transparency. Such performance achieves an increment of ≈50% when comparing to the efficiency of ≈12% that was firstly reported in 2020. In more, the T80 lifetime of ≈525h has been obtained during the quasi-maximum power point tracking test in open air (device unsealed).

Nickel oxide (NiOx) is considered an ideal hole transport layer (HTL) in inverted perovskite solar cells (PSCs) due to its excellent carrier mobility and low cost. Electron-beam-evaporated NiOx (E-beam-NiOx) exhibits exceptional commercial potential due to its process compatibility. However, there are surface defects in E-beam-NiOx, which are incompatible with perovskite (PVK) and limit its development. In this work, we used [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) as a self-assembled monolayer (SAM) and l-α-glycerylphosphorylcholine (GPC) to double modify the buried interface of E-beam-NiOx films. SAM is used to modify interface defects of NiOx, while GPC improves the wetting property and uniformity of the interface. Under the joint modification of SAM and GPC, the interface defects of NiOx films were passivated, and the hole extraction ability of HTL was improved. At the same time, the growth quality of PVK films was improved, and the energy level matching between NiOx and PVK was optimized. After optimization, the small-area (0.0575 cm2) PSCs achieved a champion power conversion efficiency (PCE) of 23.31%, providing an effective strategy and direction for the preparation of high-efficiency PSCs by E-beam-NiOx.

The inferior interfaces at both the perovskite (PVK)/SnO2 electron transport layer (ETL) and PVK/carbon electrode (C), particularly defect states and energy level misalignment, remain primary bottlenecks. Here, a bifacial modification strategy based on sodium oxamate (SO) is proposed, revealing its effective modulation of the properties at both above interfaces. Comprehensive experimental and theoretical investigations reveal that SO effectively modulates both the SnO2/PVK and PVK/C interfaces. Density functional theory (DFT) calculations coupled with experimental evidence demonstrate that SO not only optimizes the electron mobility of SnO2 and synergistically aligns the energy level gradient across the SnO2/PVK/C stack, but also facilitates effective defect passivation at both interfaces.Specifically, the carbonyl groups of SO coordinates with undercoordinated Sn⁴⁺ ions at the SnO2 surface, passivating detrimental oxygen vacancies, while the amino groups of SO bind to undercoordinated Pb2+ ions at the PVK interfaces. Furthermore, the Na+ ions significantly suppress the migration of I- ions within the PVK lattice. Consequently, the champion power conversion efficiency (PCE) of HTL-Free C-PSCs with SO delivers is 18.03%. Moreover, the prolongs lifetime over 90% of the initial PCE after 1000 h in environmental conditions. This work introduces an effective bifacial interface engineering strategy for efficient and stable HTL-free C-PSCs.

Delamination and cracking of air electrodes are two mechanical causes to the degradation of high-temperature electrochemical ceramic cells. While compositing negative thermal expansion (NTE) materials can tackle delamination by lowering the thermal expansion coefficient (TEC) of air electrode, it can exacerbate cracking due to large thermal stress between particles of NTE and positive thermal expansion perovskites (PTE). Here, we introduce interfacial oxides to "wedge" the NTE-PTE interface, thereby resisting cracking inside the bulk of the air electrode through reactive calcination at near-melting temperatures. This concept is demonstrated by compositing negative thermal expansive HfW2O8 with Ba0.5Sr0.5Co0.8Fe0.2O3-δ (perovskite), forming Co3O4, Fe3O4, BaHfO3 and Sr3WO6 as wedging phases. Enhanced bulk modulus (by 102%), hardness (by 138%), and mitigated TEC (reduced by 35%) are simultaneously achieved, which enhances the durability of the air electrode over 40 rigorous thermal cycles between 600 °C and 300 °C, and even with no decay after two years of exposure to ambient air. This method offers an effective strategy for developing mechanical-robust electrodes of high-temperature electrochemical cells.

Abstract Energy level misalignment‐induced interfacial non‐radiative recombination and interface defect‐induced carrier transport loss are key factors limiting the power conversion efficiency (PCE) of perovskite solar cells. To address these issues, this work introduces 3‐Piperidinecarboxamide (PDN) to reconstruct the surface of the 3D perovskite. PDN passivates both shallow and deep defects simultaneously, forming an n‐type quasi‐2D perovskite surface layer that enhances electron extraction and reduces the energy level barrier. Density functional theory (DFT) calculations reveal that the electron donor unit (R‐C‐NH) of PDN preferentially binds to undercoordinated Pb2+ defects sites on the perovskite (PVK) surface. The hydrogen bonding formed between the R‐NH2 group of PDN and I− ions on the [PbI6]4− octahedra enhances the above binding capability. The device adopting this strategy achieves a champion PCE of 26.10%. Furthermore, unencapsulated PSCs also exhibits excellent stability, retaining 88% of the initial PCE retained after ≈1400 h at 25 °C under 30% humidity.

Abstract Engineering additive passivators with multiple synergistic effects has emerged as an effective strategy for regulating the growth of perovskite (PVK) grains and reducing the defect density in PVK films. In this work, a spatially flexible multisite amide derivative n‐(tert‐butyl)‐4‐ureidobenzamide (NUNB) is introduced into PVK to not only passivate defects through the interactions between its spatially flexible C═O/N─H functional groups and PVK, but also regulate the crystallization process by forming hydrogen bonds with FA+/MA+, resulting in high‐quality PVK films with larger grain sizes, less residual tensile stress and lower defect densities. Meanwhile, NUNB can effectively modulate charge transport behavior, inhibit trap‐assisted non‐radiation recombination, and enhance the stability of perovskite solar cells (PSCs). Consequently, NUNB‐treated PSC achieves an excellent power conversion efficiency (PCE) of 26.34% (certified 26.03%), along with outstanding thermal and operational stability. Furthermore, the associated rigid modules substantiate this strategy of scalable potential, achieving efficiencies of up to 21.92%.

Polymer nanocomposites incorporating perovskite (PV) nanoparticles have recently emerged as highly promising materials for optoelectronic and photonic devices. In this work, steady-state and time-resolved photoluminescence (PL) were performed in PV-based polydimethylsiloxane (PDMS) nanocomposite films. The steady-state PL measurements revealed linearly increasing emission as excitation intensities ramped up, followed by a saturation. The optical limiting was scalable through the PV concentrations and is likely due to creation of maximum number of electron–hole (e–h) pairs in the system. The presence of a PDMS altered the multi-exponential PL decay significantly, both in terms of underlying mechanism and the associated timescales. The introduction of PDMS changed a 3-component exponential decay of PV into a 2-component mechanism and reduced the total timescale of decay from 16 ns to ~6 ns.

Organohalide lead perovskites (PVKs) are among the most promising materials for creating high-efficiency and low-cost photovoltaic devices. However, challenges such as high trap densities, low crystallinity, and moisture sensitivity in perovskite films hinder the performance and stability of perovskite solar cells (PSCs). In this work, we address these limitations by incorporating a green, environmentally friendly nanocomposite multi-walled carbon nanotube/zinc oxalate (MWCNT/Zn(COO)₂) into the electron transport layer (ETL) to enhance the performance, stability, and cost-effectiveness of PSCs. The novel ETL, comprising mesoporous TiO₂ (mp-TiO₂) combined with the MWCNT/Zn(COO)₂ layer, demonstrated superior charge extraction and reduced charge recombination at the ETL/perovskite interface, leading to significant performance improvements. Furthermore, the PSCs demonstrated remarkable stability, retaining over 70% of their initial power conversion efficiency (PCE) after 70 days of storage in ambient conditions without encapsulation, a substantial improvement over conventional mp-TiO₂-based devices. Additionally, replacing expensive metals, such as gold (Au), with cost-effective carbon paste further reduces production costs, enhancing the economic viability of the devices. This work highlights the potential of the MWCNT/Zn(COO)₂ nanocomposite to enhance the efficiency and stability of PSCs, paving the way for greener and more cost-effective photovoltaic technologies.

Abstract Research on tandem solar cells that include perovskite (PVK) materials has seen a remarkable advance due to their potential high efficiency since the band gap of perovskite materials can be fine-tuned in a wide range. In this work, a theoretical model that can be applied to tandem solar cells with multiple perovskite junctions is discussed. Then, results for two-terminal solar cells consisting of two and three junctions, based on Silicon (Si) and CuInSe2 (CIS), considering the PVK/Si, PVK/CIS, PVK/PVK/Si, and PVK/PVK/CIS designs are shown. The results show the efficiency limits as a function of the band gap for the perovskite junctions, reaching maximum efficiencies around 50% for the three-junction cells PVK/PVK/Si and PVK/PVK/CIS. In the more realistic case, where finite absorption by the perovskite materials is taken in account, the efficiency is estimated considering both the band gap and thickness of the perovskite junctions, while keeping the Si and CIS junctions thicknesses constant. In this case, it is shown that efficiencies greater than 42.5% can be achieved for two-junction solar cells (when the appropriate thickness and perovskite band gap are chosen). Similarly, the possible practical efficiency for the three-junction solar cells PVK/PVK/Si and PVK/PVK/CIS can be up to 47.5%. It can be concluded that tandem solar cells that combine perovskite cells with existing Si and CIS technologies can achieve higher efficiencies so that there is still room for improvements at the laboratory for current two-junction PVK/Si and PVK/CIS tandem solar cells.

Abstract The process by which pinholes formed in the perovskite (PVK) layer are transformed into current leakage paths was elucidated through model experiments and simulations. Pinholes were intentionally formed in the PVK layer using laser processing techniques. The effect of the pinholes on the performance of the perovskite solar cells (PSCs) was evaluated. In addition, device simulations show the current density-voltage characteristics and the current distribution in the PSCs with the pinholes. Immediately after the fabrication of pinholes, the pinholes did not act as the current leakage paths. However, 2 weeks of dark storage and 3 minutes of activation by Air Mass 1.5 Global (AM 1.5G) irradiation caused some formed-pinholes to transform into the current leakage paths. The device simulations indicate that before the pinhole transforms into the current leakage path, the current is concentrated at the bottom of the pinhole, and this current concentration creates a current leakage path.

Abstract The inhomogeneous Pb/Sn distribution in Sn–Pb narrow‐bandgap (NBG) perovskites (PVK), arising from divergent crystallization dynamics and Sn2+ segregation, leads to deleterious bandgap fluctuations and interfacial recombination. Herein, a multifunctional cyclodextrin derivative (MCD) additive engineered with 6–8 thiol (‐SH) groups is reported that synchronously addresses these challenges through in situ crystallization modulation and ion‐homogenization, which concurrently suppress Sn2+ oxidation through their reductive capacity and modulate crystallization kinetics via dual chelation of Pb2+/Sn2+ ions through dynamic sulfur–metal coordination bonds. Theoretical and experimental analyses reveal that this dual‐function mechanism decelerates ion migration during nucleation, enabling the growth of high‐quality NBG PVK films with suppressed defect densities and homogenized Pb/Sn distribution. This homogenization stems from MCD's multidentate thiol coordination, which forms a dynamic chelation network with Pb2+/Sn2+, regulating ion release rates and suppressing localized supersaturation. The cyclic oligosaccharide backbone further imposes steric confinement, inhibiting ion clustering and disordered nucleation. Consequently, optimized NBG PVK solar cells achieve a 22.3% power conversion efficiency with suppressed non‐radiative losses, enabling 27.9%‐efficient all‐PVK tandem solar cell with extremely high long‐term stability for 1,320 h. This work establishes molecular crowding and dynamic coordination as dual levers to control crystallization thermodynamics in multinary perovskites.

The development of efficient integrated photonic circuits is fundamental for ongoing research in information processing and computer science. The greatest challenge facing photonic systems is achieving strong nonlinearities, which are exploitable in strongly coupled systems, leading to the formation of exciton-polaritons. In this context, the use of hybrid organic-inorganic perovskites (PVKs) offers a promising alternative, exhibiting robust interactions at Room Temperature (RT). However, the development of PVK-based integrated devices requires both the ability to achieve long in-plane propagation and the development of alternative fabrication approaches tailored to PVK materials, designed to preserve their optical properties and prevent degradation. Herein, we present the realization of a proof-of-concept all-optical switch using propagating polaritons confined in Total Internal Reflection (TIR), which ensures long in-plane propagation and limited optical losses. We realized efficient injection-extraction of the TIR-confined waveguide polariton modes by employing gold grating couplers prepatterned on the substrate.

Vapor-solution two-step deposition is recognized as a promising method to fabricate monolithic perovskite/silicon tandem solar cells (TSCs) on commercial silicon cell substrates with fully textured surfaces. Although a certified power conversion efficiency (PCE) of 31.3% is recorded for small size perovskite/silicon TSCs, scaling up from spin-coating used for small sizes to the slot-die for large areas has become the main challenge for its further mass production due to the residual PbI2 and increased internal voids in perovskite (PVK) films. In this study, sodium 2,5-difluorobenzoate (2,5-NaDPA) is utilized to reduce nucleation energy barrier difference at various convex angles on PbI2 layer, delaying the growth of perovskite crystals, and effectively promoting the grain size of perovskites, which is particularly favorable for perovskites deposited on commercial textured Si substrates. Eventually, the voids of large area PVK films are greatly restrained. A high efficiency of 28.28% is obtained from a fully textured perovskite/silicon tandem device prepared in ambient condition with an effective area of 19.9 cm2. This work paves a new method for commercial production of large area perovskite/silicon TSCs.

Abstract To meet the growing demand for eco-friendly solar technologies, lead-free perovskite (PVK) materials are emerging as promising alternatives to their lead-based counterparts. Among these, ASnI2Br stands out due to its suitable wide bandgap, making it a strong candidate for integration into both 4T and 2T tandem configurations. In pursuit of a fully eco-friendly solar cell design, we present the development of lead-free ASnI2Br/Si tandem solar cells, offering a sustainable approach with high potential for efficiency improvements. First, the advancement of 4 T tandem cell efficiency is discussed. The main structure consists of FTO/PEDOT:PSS/ASnI2Br-PVK/C60/BCP/Ag inverted structure as the top cell and an n-type Si as the rear cell. Based on the simulation findings, the suggested top cell structure performs much better when TiO2 is substituted as the electron transport layer instead of C60, while CuSCN is found to be a good replacement for PEDOT:PSS as a hole transport layer. With these changes, the top cell's efficiency becomes 15.29%. In addition, optimizations for the bottom cell are carried out. Efficiencies for bare and filtered bottom cells reaching 23.97 and 12.53% are achieved, respectively, at 30 µm absorber thickness and 1 ms lifetime. With only two terminals, the 2 T cell has fewer manufacturing costs for the photovoltaic module than the 4 T cell. Thus, we introduce a design for a 2 T cell by converting the enhanced 4 T cell, while inverting the top cell to be compatible with the rear cell n-p structure. To ensure current matching, the correct thickness must be established for both sub-cells, where the thickness of the perovskite absorption layer rises from 200 to 545 nm. This led to reaching the matching point at a current equal to 16.35 mA/cm2, and our simulation for the monolithic stacked 2T TSC produced a PCE of 24.28%.

Calcium perovskite is a major component of deep mantle phase assemblages and has been frequently identified, in retrograde form, as polyphase mineral inclusions within sub-lithospheric diamonds. Here experimental observations of synthetic samples demonstrate various properties of calcium perovskite minerals which have relevance for the interpretation of diamond-hosted inclusions. Ambient pressure diffraction and spectroscopy confirm the linear dependence of crystallographic unit cell volume and Raman peak shifts across the entire CaSiO3-CaTiO3 binary join. These systematics will allow verification of perovskite structure and constraint of inclusion composition, without destructive analyses, in future studies. Additionally, high pressure observations confirm that calcium perovskite minerals ≳ 80 mol.% CaSiO3 undergo spontaneous amorphization during decompression at room temperature, meaning they are unrecoverable. Finally, the presence of water appears to expand the calcium perovskite stability field to lower pressure conditions, implying at least some appreciable water-solubility in these minerals.

An intermediate mirror has been proposed to enhance multijunction solar cell efficiency by selectively reflecting the light beyond higher energy bandgap of top cell, while simultaneously transmitting the rest of lower-energy light. Therefore, it reduces the higher-energy absorption spectral tail of the bottom cell (thermalization loss) and increase the absorption in the top cell. However, its effectiveness has only been theoretically validated in simplified tandem with basic components such as an antireflection coating (ARC) and top/bottom absorbers. In contrast, experimentally optimized tandem cells, such as perovskite (PVK)/silicon (Si) two-terminal configurations, include additional stacked electrodes, ultrathinned intermediate electrode, and random textures to maximize efficiency. Herein, we revisited the role of the intermediate mirror in these advanced tandem cells. Our results show that the incorporation of ideal intermediate mirror (IIM) does not improve efficiency both in textured and flat tandem cells, with its theoretical upper limit of efficiency being similar to or even lower than that of experimentally optimized cells.

Abstract The two‐step method for perovskite solar cells (PSCs) offers a promising technology for scalable manufacturing, particularly under ambient air conditions, due to its inherent simplicity, high reproducibility, and operational convenience. With this approach, achieving high‐quality of lead iodide (PbI2) films during the initial stage is paramount to ensuring the overall performance and stability of the devices. However, during the ambient fabrication of PbI2, the residual high boiling point and hygroscopic dimethyl sulfoxide (DMSO) solvent significantly compromises the resulting film quality. Here, L‐Homoarginine hydrochloride (HargCl) is introduced into the PbI2 precursor solution, which greatly reduced the residual amount of PbI2·xDMSO and passivated the internal defects of perovskite (PVK) films. By leveraging this strategy, inverted perovskite solar cells entirely in the air are successfully prepared, achieving an impressive power conversion efficiency (PCE) of 25.05% — the highest reported efficiency to date for two‐step fully air‐processed inverted PSCs. In addition, these unencapsulated devices maintained 96% of their initial power conversion efficiency after 500 h storage in the air with 20–40% RH.