Search

Formamidinium lead triiodide (FAPbI3) perovskite without methylammonium and/or Cs cations is considered the most promising candidate for perovskite photovoltaics. However, the crystallization of photoactive α‐FAPbI3 requires high‐temperature annealing (≥150 °C) and a controlled humidity environment when methylammonium‐containing additives are absent. A methylammonium‐free ink is reported that enables low‐temperature (≤80 °C) crystallization of photoactive α‐FAPbI3 films, while also demonstrating compatibility with blade‐coating large‐area films in ambient air. The synergistical effects of methylphenyl sulfoxide and PbCl2 facilitate the formation of an intermediate phase of nanoscale‐disordered δ‐FAPbI3, which dramatically reduces the crystallization temperature of α‐FAPbI3 down to 80 °C and even below. The 80 °C crystalized α‐FAPbI3 exhibits reduced strain and improved uniformity compared to high‐temperature annealed counterparts. The synthesized ink and the corresponding intermediate precursor film are also found remarkably stable, allowing open‐air processing without the need for humidity control. Highly efficient n–i–p structured α‐FAPbI3 minimodules can be fabricated under an ambient environment RH 50% with the ink at 80 °C, achieving a power conversion efficiency of up to 22.4%. The discovery of the low‐temperature FAPbI3 ink paves a new avenue for printing perovskite solar cells and associated optoelectronic applications, accelerating the commercialization progress of perovskite materials. [ABSTRACT FROM AUTHOR]

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since January 2024 are reviewed. [ABSTRACT FROM AUTHOR]

A method for measuring light absorption using photothermal deflection spectroscopy (PDS) is investigated. Typical reflectance and transmittance (R & T) absorption measurements have low spectral resolution (SR) with standard setups. It is believed that absorption measurements using PDS solve this problem because of its high sensitivity, even at a high SR. However, accurate absorption measurements have not been obtained using conventional PDS. The reflectance of the sample must be considered in the absorptance calculations. Various absorption measurement methods are compared and a novel calculation method for accurate PDS absorption measurements is proposed. A sample with quantum structures is fabricated and PDS measurements are performed. Exciton absorption peaks are also observed. The high SR of PDS is demonstrated and the measured exciton absorption peaks are confirmed using piezoelectric photothermal measurements. Furthermore, it is confirmed that the absolute values of absorptance derived from the R & T and PDS measurements agree well. The new PDS absorption measurement technique enables to obtain accurate absorption characteristics, which are indispensable for designing and optimizing optoelectronic devices. [ABSTRACT FROM AUTHOR]

Multidimensional simulations for diverse solar cells often encounter distinctive configurations, even when employing the same simulation software. The complexity and inefficiency of this process are further exacerbated when employing different simulators. From our extensive decade‐long experience in numerical simulations of diverse solar cells, we have identified ten common simulation steps intrinsic to typical electrical and optical simulations. Subsequently, we propose ten sets of variables that encompass all the relevant details required for these steps. To address the challenge of varying information requirements for each variable across different simulations, we assign a list, a versatile data type, to each variable. This approach, by design, enables concise, coherent, and flexible input, accommodating the unique demands of each simulation. However, to ensure unambiguous simulations, precise specifications for these variables are essential. Computer code has been successfully implemented to ensure adherence to specifications and expedite variable synchronization with Sentaurus, the de facto standard for device simulation. Within this framework, users are only tasked with editing variables in a plain text file, obviating the need for in‐depth knowledge of Sentaurus. This streamlines the prerequisites for engaging in numerical simulation significantly. Through thoughtful design considerations, we preserve the simulation capacity while simultaneously enhancing productivity considerably. This open‐source framework welcomes global collaboration within the photovoltaic community and has the potential to generate an extensive dataset for cost‐effective artificial intelligence training. [ABSTRACT FROM AUTHOR]

Oleanolic acid (OA) is a pentacyclic triterpene with reported protective effects against various diseases, including diabetes, hepatitis, and different cancers. However, the effects of OA on obesity‐induced muscle atrophy remain largely unknown. This study investigated the effects of OA on skeletal muscle production and proliferation of C2C12 cells. We report that OA significantly increased skeletal muscle mass and improved glucose intolerance and insulin resistance. OA inhibited dexamethasone (Dex)‐induced muscle atrophy in C2C12 myoblasts by regulating the PI3K/Akt signaling pathway. In addition, it also inhibited expression of MuRF1 and Atrogin1 genes in skeletal muscle of obese mice suffering from muscle atrophy, and increased the activation of PI3K and Akt, thereby promoting protein synthesis, and eventually alleviating muscle atrophy. Taken together, these findings suggest OA may have potential for the prevention and treatment of muscle atrophy. [ABSTRACT FROM AUTHOR]

Poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine (PTAA) is one of the most efficient hole transport materials for p–i–n structured perovskite solar cells (PSCs). However, the hydrophobicity of PTAA causes wettability problems and is thereby associated with low yield and poor reproducibility. Herein, a new strategy for improving the perovskite precursor wettability on PTAA is developed. A Cu2(Thiourea)Br2 complex interfacial layer is introduced on the PTAA, improving the coverage of perovskite precursors and thereby the perovskite film. Partially dissolved Cu2(Thiourea)Br2 in the perovskite absorber further enhances band alignment and carrier extraction between layers. With the addition of Cu2(Thiourea)Br2 layer on nondoped PTAA, PSCs in p–i–n structure with a bandgap of 1.63 eV have achieved over 21% efficiency both on 0.1 and 1.0 cm2 sized devices with a significantly improved yield and reproducibility. Unencapsulated devices retain 100% of their initial efficiency after 2000 h at 65 °C. [ABSTRACT FROM AUTHOR]

Human skin comprises multiple hierarchical layers that perform various functions such as protection, sensing, and structural support. Developing electronic skin (E‐skin) with similar properties has broad implications in health monitoring, prosthetics, and soft robotics. While previous efforts have predominantly concentrated on sensory capabilities, this study introduces a hierarchical polymer system that not only structurally resembles the epidermis‐dermis bilayer structure of skin but also encompasses sensing functions. The system comprises a polymeric hydrogel, representing the "dermis", and a superimposed nanoporous polymer film, forming the "epidermis". Within the film, interconnected nanoparticles mimic the arrangement of interlocked corneocytes within the epidermis. The fabrication process employs a robust in situ interfacial precipitation polymerization of specific water‐soluble monomers that become insoluble during polymerization. This process yields a hybrid layer establishing a durable interface between the film and hydrogel. Beyond the structural mimicry, this hierarchical structure offers functionalities resembling human skin, which includes (1) water loss protection of hydrogel by tailoring the hydrophobicity of the upper polymer film; (2) tactile sensing capability via self‐powered triboelectric nanogenerators; (3) built‐in gold nanowire‐based resistive sensor toward temperature and pressure sensing. This hierarchical polymeric approach represents a potent strategy to replicate both the structure and functions of human skin in synthetic designs. [ABSTRACT FROM AUTHOR]

The organic spacer cation plays a crucial role in determining the exciton fine structure in 2D perovskites. Here, magneto‐optical spectroscopy is used to gain insight into the influence of the organic spacer on dark excitons in Ruddlesden–Popper (RP) perovskites. Using modest magnetic field strengths (<1.5 T), the optically forbidden dark exciton state can be identified and its emission properties significantly modulated via application of in‐plane magnetic fields, up to temperatures of 15 K. At low temperatures, an increase in collected photoluminescence efficiency of >30% is demonstrated, signifying the critical role of the dark exciton state for light‐emitting applications of 2D perovskites. The exciton fine structure and the degree of magnetic‐field‐induced mixing are significantly impacted by the choice of organic spacer cation, with 4–methoxyphenylethylammonium (MeO‐PEA) showing the largest effect due to larger bright–dark exciton splitting. This study distinguishes between interior (bulk) and surface dark‐exciton emission, showing that bright–dark exciton splitting differs between the interior and surface. The results emphasize the significance of the organic spacer cation in controlling the exciton fine structure in 2D perovskites and have important implications for the development of optoelectronic technology based on 2D perovskites. [ABSTRACT FROM AUTHOR]

Tandem solar cells are rationally designed and fabricated by stacking multiple subcells to achieve power conversion efficiency well above the Shockley‐Queisser (SQ) limit. There is a large selection pool for the subcell candidates, such as Si, III–V, Kesterite, Perovskite, and organic solar cells. A series of different combinations of these subcells have been successfully demonstrated in practical tandem solar cell devices. However, there has not been a systematic summary of how to connect subcells in a tandem solar cell using a practical, cost‐effective, and efficiency‐beneficial fashion. In this work, the connection manners of subcells within a tandem cell are classified into three main categories, performing sequential growth, using the physical connection, and applying an intermediate layer, focusing on systematical description of intermediate layers using different materials. The advantages and disadvantages of these connection methods and their applicability to tandem cell types are further elaborated using two typical example models, III–V/Si and Perovskite inclusive tandem cell devices. Eventually, this work can provide useful guidance on how to carry out a suitable intermediate connection in the design of tandem solar cells depending on the selected subcells and device structure. [ABSTRACT FROM AUTHOR]

This article, titled "Methylammonium-Free Ink for Low-Temperature Crystallization of α-FAPbI3 Perovskite," was published in the journal Advanced Energy Materials. The authors, Tian Hou, Meng Zhang, Xiaoran Sun, Yihao Wang, Kaipeng Chen, Zhipeng Fu, Mingrui He, Xu Liu, Ziheng Liu, Yuelong Huang, Martin A. Green, and Xiaojing Hao, discuss a new method for fabricating α-FAPbI3 perovskite at low temperatures without the use of methylammonium (MA). The article includes an image illustrating the phase transition from hexagonal δ-FAPbI3 to cubic α-FAPbI3, and explains how the addition of PbCl2 and MPSO helps facilitate this transition. For more details, readers are directed to the full article. [Extracted from the article]

Cd‐free high‐bandgap Cu2ZnSnS4 (CZTS) solar cells are expected to offer green and low‐cost solutions to single‐junction and tandem photovoltaic markets. Despite attracting considerable attention in past years, reported certified efficiency has yet to exceed the 10% threshold. Sn‐related defects, especially those originating from Sn2+ oxidation states, lead to severe recombination loss and limit device performance. Here, the formation of these detrimental defects is suppressed by creating a more benign chemical environment during sulfurization annealing. With dominant Sn4+ states in the source material and the precursor, the oxidation state of Sn remains primarily in its native Sn4+ state during annealing and in the final film. Engineering the Sn‐related defects leads to shallower tail states in bulk CZTS and fewer interfacial defects. As a result, both radiative and non‐radiative recombination losses are alleviated, contributing to a certified 10.7% efficiency of the Cd‐free high‐bandgap CZTS solar cell. This strategy may advance various kesterite materials and other technologies with multivalent constituents. [ABSTRACT FROM AUTHOR]

Reducing non-radiative recombination and addressing band alignment mismatches at interfaces remain major challenges in achieving high-performance wide-bandgap perovskite solar cells. This study proposes the self-organization of a thin two-dimensional (2D) perovskite BA 2 PbBr 4 layer beneath a wide-bandgap three-dimensional (3D) perovskite Cs 0.17 FA 0.83 Pb(I 0.6 Br 0.4 ) 3 , forming a 2D/3D bilayer structure on a tin oxide (SnO 2 ) layer. This process is driven by interactions between the oxygen vacancies on the SnO 2 surface and hydrogen atoms of the n-butylammonium cation, aiding the self-assembly of the BA 2 PbBr 4 2D layer. The 2D perovskite acts as a tunneling layer between SnO 2 and the 3D perovskite, neutralizing the energy level mismatch and reducing non-radiative recombination. This results in high power conversion efficiencies of 21.54% and 19.16% for wide-bandgap perovskite solar cells with bandgaps of 1.7 and 1.8 eV, with open-circuit voltages over 1.3 V under 1-Sun illumination. Furthermore, an impressive efficiency of over 43% is achieved under indoor conditions, specifically under 200 lux white light-emitting diode light, yielding an output voltage exceeding 1 V. The device also demonstrates enhanced stability, lasting up to 1,200 hours., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

The reversal of halide ions is studied under various conditions. However, the underlying mechanism of heat-induced reversal remains unclear. This work finds that dynamic disorder-induced localization of self-trapped polarons and thermal disorder-induced strain (TDIS) can be co-acting drivers of reverse segregation. Localization of polarons results in an order of magnitude decrease in excess carrier density (polaron population), causing a reduced impact of the light-induced strain (LIS - responsible for segregation) on the perovskite framework. Meanwhile, exposing the lattice to TDIS exceeding the LIS can eliminate the photoexcitation-induced strain gradient, as thermal fluctuations of the lattice can mask the LIS strain. Under continuous 0.1 W cm⁻ 2 illumination (upon segregation), the strain disorder is estimated to be 0.14%, while at 80 °C under dark conditions, the strain is 0.23%. However, in situ heating of the segregated film to 80 °C under continuous illumination (upon reversal) increases the total strain disorder to 0.25%, where TDIS is likely to have a dominant contribution. Therefore, the contribution of entropy to the system's free energy is likely to dominate, respectively. Various temperature-dependent in situ measurements and simulations further support the results. These findings highlight the importance of strain homogenization for designing stable perovskites under real-world operating conditions., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

The Cd-free Cu 2 ZnSnS 4 (CZTS) solar cell is an ideal candidate for producing low-cost clean energy through green materials owing to its inherent environmental friendliness and earth abundance. Nevertheless, sulfide CZTS has long suffered from severe open-circuit voltage (V OC ) deficits, limiting the full exploitation of performance potential and further progress. Here, an effective strategy is proposed to alleviate the nonradiative V OC loss by manipulating the phase evolution during the critical kesterite phase formation stage. With a Ge cap layer on the precursor, premature CZTS grain formation is suppressed at low temperatures, leading to fewer nucleation centers at the initial crystallization stage. Consequently, the CZTS grain formation and crystallization are deferred to high temperatures, resulting in enhanced grain interior quality and less unfavorable grain boundaries in the final film. As a result, a champion efficiency of 10.7% for Cd-free CZTS solar cells with remarkably high V OC beyond 800 mV (63.2% Schockley-Queisser limit) is realized, indicating that nonradiative recombination is effectively inhibited. This strategy may advance other compound semiconductors seeking high-quality crystallization., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)