RESUMEN
AIM: To explore the disruptive influence of workplace gaslighting behaviours and mobbing on nurses' career entrenchment across multiple healthcare centres. DESIGN: A multi-centre cross-sectional. METHODS: Data were collected from 483 nurses from various healthcare settings in Egypt, spanning from January 2024 to February 2024. The Gaslighting at Work Questionnaire, Luxembourg Workplace Mobbing Scale and Career Entrenchment Scale were employed for data collection. RESULTS: The study revealed moderate levels of gaslighting, mobbing and nurses' career entrenchment. Also, there is a negative correlation between nurses' career entrenchment and both gaslighting and mobbing, while gaslighting and mobbing exhibit a positive correlation. The study also highlighted regional disparities in the prevalence of these phenomena, with the highest incidences noted in urban healthcare settings. CONCLUSION: The findings underscore the critical impact of workplace gaslighting and mobbing on nurses' career entrenchment. REPORTING METHOD: The relevant reporting method has been adhered to, that is, STROBE. IMPLICATION FOR THE PROFESSION: The future of the nursing profession requires building productive nurses who can cope with negative workplace experiences. This could be achieved by cultivating a workplace culture that has zero tolerance for these experiences. Offering counselling services or employee assistance programmes to help nurses cope with the emotional toll of these negative experiences is a promising strategy. IMPACT: This study is the first to examine serious workplace practices like gaslighting and mobbing in a nursing context, emphasizing their effect on nursing-sensitive indicators like career entrenchment. It is one of the important initiatives geared towards upgrading the competitiveness and magnetism of healthcare organizations in the era of green human resources management. Results provide valuable insights for nurse leaders to control nursing turnover and shortage crises in different endeavours. PATIENT OR PUBLIC CONTRIBUTION: In our study, nurses from diverse geographical regions and varied specialties actively participate, offering a rich tapestry of experiences and perspectives.
RESUMEN
BACKGROUND: Controlling smartphone addiction and procrastination among nurses is crucial for enhancing the productivity of both nursing and the healthcare system. Critical care nurses are highly vulnerable to smartphone addiction and procrastination behaviors than other groups. They may purposefully delay their tasks, a practice known as active procrastination, or inadvertently delay them, a practice known as passive procrastination. AIM: This study was designed to assess the prevalence of smartphone addiction and procrastination behavior among nurses, examine the effect of smartphone addiction on the active and passive procrastination behaviors, and explore the correlation between active and passive procrastination behaviors among nurses. METHOD: This is a descriptive correlational exploratory study that was conducted at 23 critical care units of one large educational hospital in Egypt. Data were collected from 360 nurses who were conveniently selected using three tools: the Smartphone Addiction Inventory, the New Active Procrastination Scale, and the Unintentional Procrastination Scale. Correlation and regression analyses were conducted to test the hypothetical relationship among the study variables. RESULTS: This study revealed that 55.0%, 80.0%, and 45.3% of nurses had a moderate perceived level of smartphone addiction, active procrastination behavior, and passive procrastination behavior, respectively. There is a significant positive correlation between smartphone addiction and both nurses' active and passive procrastination behaviors. Smartphone addiction accounts for 25% of the variance in nurses' active procrastination behavior and 18% of the variance in their passive procrastination. Furthermore, there is a moderately significant negative correlation between nurses' active procrastination behavior and their passive procrastination behavior. CONCLUSION: Nurses are exhibiting moderate levels of smartphone addiction and procrastination, which is a significant threat to the healthcare industry and nursing productivity. This requires technological, educational, and organizational interventions that foster active procrastination and combat passive procrastination behaviors among nurses. IMPLICATIONS: Continuous training programs are required to enhance time management skills among nurses and increase the awareness of nurse managers with the symptoms of smartphone addiction among nurses. Nurse leaders should early detect and address the addictive use of smartphones among nurses, identify potential procrastinators, and provide counseling to eradicate these behaviors in the workplace.
RESUMEN
Two-dimensional hybrid organic-inorganic perovskites with chiral spin texture are emergent spin-optoelectronic materials. Despite the wealth of chiro-optical studies on these materials, their charge-to-spin conversion efficiency is unknown. We demonstrate highly efficient electrically driven charge-to-spin conversion in enantiopure chiral perovskites (R/S-MB)2(MA)3Pb4I13 (ãnã = 4), where MB is 2-methylbutylamine, MA is methylamine, Pb is lead, and I is iodine. Using scanning photovoltage microscopy, we measured a spin Hall angle θsh of 5% and a spin lifetime of ~75 picoseconds at room temperature in ãnã = 4 chiral perovskites, which is much larger than its racemic counterpart as well as the lower ãnã homologs. In addition to current-induced transverse spin current, the presence of a coexisting out-of-plane spin current confirms that both conventional and collinear spin Hall conductivities exist in these low-dimensional crystals.
RESUMEN
AIM: This study was designed to examine the relationship between humble leadership and nurses' turnover intention and investigate the moderating role of leader expertise in this relationship. BACKGROUND: Leader humility and expertise are two key dimensions of professional spirit in competitive magnet organizations. Many organizational factors could make nurses take a decision to leave their organization; however, leader humility and expertise could help nurses retract from this decision. METHOD: This is a multisite cross-sectional study that was conducted at all medical-surgical units of four university hospitals. Using scales for assessing leader humility, nurses' turnover intention, and leader expertise, 385 nurses were surveyed. Data were investigated via descriptive and inferential statistics, where correlation, path analysis, and structured equation modeling were used to test the hypothetical relationship among study variables. RESULTS: There is a statistically significant negative relationship between humble leadership and nurses' turnover intention. Humble leadership and leader expertise were significant predictors of nurses' turnover intention. The moderating effect of leader expertise on the relationship between humble leadership and nurses' turnover intention was statistically significant, making it more negative, implying that leader expertise amplifies the effect of leader humility on reducing nurses' turnover. CONCLUSION: Incorporating leader expertise with humility could provide an efficient panacea for reducing turnover intentions among nurses in different healthcare organizations. IMPLICATIONS FOR NURSING AND HEALTH POLICY: Healthcare organizations could develop an efficient retention plan for nurses by cultivating humility among both leaders and nurses. In addition, building nurse leaders' expertise through opening avenues for professional development is a good strategy in the face of nurses' shortage and high turnover. Furthermore, succession planning in healthcare organizations must consider humility as a vital skill among anticipated leaders.
RESUMEN
Background and Objectives: Stenotrophomonas maltophilia is an opportunistic pathogen causing nosocomial infections. Diclofenac is an anti-inflammatory drug that is considered a non-antibiotic drug. This study assessed the antibacterial and antibiofilm effects of diclofenac and levofloxacin/diclofenac combination against levofloxacin resistant isolates. Materials and Methods: Minimum inhibitory concentration was determined using broth microdilution method for levofloxacin, diclofenac, and levofloxacin/diclofenac combination. Biofilm forming capacity and biofilm inhibition assay were determined. Relative gene expression was measured for efflux pump genes; smeB, and smeF genes and biofilm related genes rmlA, spgM, and rpfF without and with diclofenac and the combination. Results: Diclofenac demonstrated MIC of 1 mg/ml. The combination-with ½ MIC diclofenac-showed synergism where levofloxacin MIC undergone 16-32 fold decrease. All the isolates that overexpressed smeB and smeF showed a significant decrease in gene expression in presence of diclofenac or the combination. The mean percentage inhibition of biofilm formation with diclofenac and the combination was 40.59% and 46.49%, respectively. This agreed with biofilm related genes expression investigations. Conclusion: Diclofenac showed an antibacterial effect against Stenotrophomonas maltophilia. The combination showed in-vitro synergism, significant reduction in biofilm formation and in the relative level of gene expression. Furthermore, it can potentiate the levofloxacin activity or revert its resistance.
RESUMEN
BACKGROUND: Carpal tunnel syndrome (CTS) is a prevalent condition characterized by hand pain, tingling, and numbness. The severity of symptoms and functional status in CTS patients may be influenced by perceived stress and how individuals cope with it. However, scarce knowledge exists about the role of coping strategies as moderators in this relationship. Unfolding the role of perceived stress and coping strategies for CTS management will help the nurse to provide comprehensive and tailored nursing care. This will ultimately improve patient comfort, functionality, and quality of life. PURPOSES: This study aimed to examine the role of coping strategies (adaptive and maladaptive) in the relationship between perceived stress and both symptoms severity and function status among those patients. METHOD: We employed a multisite, correlational study design with moderation analysis. The study included 215 patients with CTS from neurosurgery outpatient clinics at three hospitals in Egypt. After obtaining their consent to participate, eligible participants completed anonymous, self-reported measures of perceived stress, the brief COPE inventory, and the Boston Carpal Tunnel Questionnaire. Demographic and biomedical data were also collected. The questionnaire took about 20 min to be completed. The data was collected over six months, starting in February 2023. RESULTS: The results showed that perceived stress, adaptive coping, and maladaptive coping were significant predictors of symptoms severity and functional status. Adaptive coping moderated the relationships between perceived stress and both symptoms severity and function status, while maladaptive coping did not. The interaction between perceived stress and adaptive coping explained a moderate effect on symptoms severity and function status after controlling for the main effects and the covariates. CONCLUSION: This study explored the relationship between perceived stress, coping strategies, and outcomes in patients with CTS. The results indicate that nurses play a vital role in assessing and assisting patients to adopt effective coping strategies to manage perceived stress and alleviate symptoms and functional impairment. Moreover, the findings support the need for psychological interventions that address both perceived stress and coping strategies as a way to enhance the functioning status and quality of life of patients with CTS.
RESUMEN
BACKGROUND: Stress and conflict in emergency departments are inevitable but can be managed. A supportive work environment is key to helping emergency care providers, especially nurses, constructively manage work-related stress and conflict. AIM: The aim of this study was to assess the influence of supportive work environments on work-related stress and conflict management style among emergency care nurses. METHODS: A descriptive correlational research design was utilized. Data were collected from 221 staff nurses recruited from two university hospital emergency departments in Alexandria, Egypt. Three instruments were used: (1) perceived organizational support scale, (2) nurses' occupational stressors scale, and (3) conflict management style inventory. RESULTS: There was a highly significant correlation between supportive work environments and work-related stress (p = .000) and a significant correlation between supportive work environments and conflict management style (p = .026). Supportive work environments had a significant inverse negative relationship with work-related stress experienced by nurses (p = .001) and accounted for 51% of variance in work-related stress. Meanwhile, supportive work environments had a significant positive relationship with conflict management styles of nurses (p = .026). Work-related stress had a significant relationship with nurses' conflict management style (p = .000) and accounted for 45% of the variance in conflict management style. LINKING EVIDENCE TO ACTION: The style of conflict management modeled by staff within emergency departments can positively or negatively influence the work environment and level of work-related stress. There is a necessity to cultivate a supportive culture for nurses in emergency departments to develop skills for constructive conflict management styles to reduce work-related stress.
Asunto(s)
Servicios Médicos de Urgencia , Personal de Enfermería en Hospital , Estrés Laboral , Humanos , Conflicto Psicológico , Condiciones de Trabajo , Encuestas y CuestionariosRESUMEN
AIM: This study aims to explore the relationship between collaborative leadership and nurses' productive work performance as well as the mediating role of nurses' innovative behavior in this relationship. BACKGROUND: Collaborative leadership is an imperative necessity in the contemporary turbulent healthcare environment as it provides a collaborative atmosphere where innovative behavior and productive performance of nurses are fostered, hence moving healthcare organizations toward competitiveness and sustainability. METHOD: A cross-sectional descriptive correlational exploratory research design was used to conduct the study. Data were collected from 550 nurses recruited from three large university hospitals in Alexandria, Egypt, using three instruments, namely, interprofessional collaborative leadership in healthcare teams scale, productive work performance questionnaire, and innovative behavior inventory. The instruments of the study are Likert-type questionnaires through which nurses' perspectives regarding study variables were investigated. We used descriptive statistics, inferential statistics as well as structured equation modeling (SEM). RESULTS: SEM revealed that collaborative leadership accounted for 83% of the variance of individual productive work performance and 77% of the variance of nurses' innovative behavior. Moreover, nurses' innovative behavior partially mediates the relationship between collaborative leadership and their productive work performance. CONCLUSION: Collaborative leadership practices are powerful strategies to enhance the innovative behavior of nurses and sustain their productive work performance. IMPLICATIONS FOR NURSING AND HEALTH POLICY: Fostering a collaborative atmosphere in workplace is mandatory for nurses' innovativeness. Replacing hierarchal leadership styles with collaborative ones is a promising strategy to enhance the productive performance of nurses. Healthcare managers and leaders could cultivate an interprofessional collaborative culture in the workplace in order to sustain productivity and eradicate counterproductive work behaviors among healthcare providers.
RESUMEN
BACKGROUND: Perioperative missed nursing care is a serious issue that can compromise patient safety and quality of care. However, little is known about the factors that influence perioperative missed nursing care. AIM: This study aimed to examine the effects of job embeddedness and polychronicity on perioperative missed nursing care as well as to test the mediating role of polychronicity on the relationship between job embeddeness and perioperative missed nursing care. METHOD: This was a cross-sectional correlational study that used a convenience sample of 210 operating room nurses from nine hospitals in Egypt. Data were collected using self-administered questionnaires that measured job embeddedness, polychronicity, and perioperative missed nursing care. Structural equation modeling was used to test the hypothesized relationships among the variables. RESULTS: The findings demonstrated a significant negative and moderate association between missed perioperative care and both nurses' job embeddedness and polychronicity. Moreover, there was a moderately positive and significant correlation between polychronicity and job embeddedness. Path analysis revealed a significant positive causal effect between job embeddedness and polychronicity. The results of mediation revealed that the indirect effect of job embeddedness on missed care through polychronicity was statistically significant; suggesting that polychronicity partially mediated this relationship. CONCLUSION: This study sheds light on the intricate relationship between nurses' job embeddedness, missed care, and polychronicity in the operating theater context. By enhancing job embeddedness and fostering polychronicity among nurses, healthcare organizations can reduce perioperative missed care and ultimately improve patient care outcomes in this critical healthcare setting.
RESUMEN
BACKGROUND: Clinical experience is an important component of nursing education because it translates students' knowledge into practice, which serves as the cornerstone of nursing practice in health care delivery. PURPOSE: The study aims to explore the quality attributes required for optimizing the training system of nursing internship students using Kano model. METHODS: A concurrent exploratory sequential triangulation design was used for mixed-methods research. A total of 295 nursing internship students (Target Population) were recruited (whole-population sampling) from the study settings in Egypt. Of them, 280 (97.2%) agreed to participate in the study and completed the interview and the self-administered questionnaire. Data collection was done over 6 months from February to August, 2022. Inferential statistics and thematic data analysis were used to analyze the results. RESULTS: Findings revealed that there were 35 fundamental attributes required for high-quality nursing students' internship training. Kano model was used to categorize and prioritize the 35 quality attributes. Kano analysis revealed that 22 attributes were categorized as "attractive" and 11 attributes were as categorized as "must be" and two were indifferent attributes. CONCLUSION: Incorporating the voice of nurse interns during their training is the key to providing efficient and high-quality internship training experience. It could give realistic impressions about the drawbacks of training and proposed solutions. IMPLICATIONS OF THE STUDY: Nurse managers and educators in clinical settings and educational institutions should put much emphasis on the training attributes and pillars to ensure that nursing internship students are mastering the skills of competent alumni. Provision of conducive training environment that fulfill the basic needs of internship students to maintain passion for learning as well as commitment of internship students to nursing profession will improve the satisfaction level and quality of education, training, and practice. Also, incorporating internship students support system with motivation strategies are helpful tools to maintain exemplary performance of internship students during the training period.
RESUMEN
Organic-inorganic metal hybrids with their tailorable lattice dimensionality and intrinsic spin-splitting properties are interesting material platforms for spintronic applications. While the spin decoherence process is extensively studied in lead- and tin-based hybrids, these systems generally show short spin decoherence lifetimes, and their correlation with the lattice framework is still not well-understood. Herein, we synthesized magnetic manganese hybrid single crystals of (4-fluorobenzylamine)2MnCl4, ((R)-3-fluoropyrrolidinium)MnCl3, and (pyrrolidinium)2MnCl4, which represent a change in lattice dimensionality from 2D and 1D to 0D, and studied their spin decoherence processes using continuous-wave electron spin resonance spectroscopy. All manganese hybrids exhibit nanosecond-scale spin decoherence time τ2 dominated by the symmetry-directed spin exchange interaction strengths of Mn2+-Mn2+ pairs, which is much longer than lead- and tin-based metal hybrids. In contrast to the similar temperature variation laws of τ2 in 2D and 0D structures, which first increase and gradually drop afterward, the 1D structure presents a monotonous rise of τ2 with the temperatures, indicating the strong correlation of spin decoherence with the lattice rigidity of the inorganic framework. This is also rationalized on the basis that the spin decoherence is governed by the competitive contributions from motional narrowing (prolonging the τ2) and electron-phonon coupling interaction (shortening the τ2), both of which are thermally activated, with the difference that the former is more pronounced in rigid crystalline lattices.
RESUMEN
2D materials with ferroelectric and piezoelectric properties are of interest for energy harvesting, memory storage and electromechanical systems. Here, we present a systematic study of the ferroelectric properties in NbOX2 (X = Cl, I) across different spatial scales. The in-plane ferroelectricity in NbOX2 was investigated using transport and piezoresponse force microscopy (PFM) measurements, where it was observed that NbOCl2 has a stronger ferroelectric order than NbOI2. A high local field, exerted by both PFM and scanning tunneling microscopy (STM) tips, was found to induce 1D collinear ferroelectric strips in NbOCl2. STM imaging reveals the unreconstructed atomic structures of NbOX2 surfaces, and scanning tunneling spectroscopy was used to probe the electronic states induced at defect (vacancy) sites.
RESUMEN
Multilayers consisting of alternating soft and hard layers offer enhanced toughness compared to all-hard structures. However, shear instability usually exists in physically sputtered multilayers because of deformation incompatibility among hard and soft layers. Here, we demonstrate that 2D hybrid organic-inorganic perovskites (HOIP) provide an interesting platform to study the stress-strain behavior of hard and soft layers undulating with molecular scale periodicity. We investigate the phonon vibrations and photoluminescence properties of Ruddlesden-Popper perovskites (RPPs) under compression using a diamond anvil cell. The organic spacer due to C4 alkyl chain in RPP buffers compressive stress by tilting (n = 1 RPP) or step-wise rotational isomerism (n = 2 RPP) during compression, where n is the number of inorganic layers. By examining the pressure threshold of the elastic recovery regime across n = 1-4 RPPs, we obtained molecular insights into the relationship between structure and deformation resistance in hybrid organic-inorganic perovskites.
RESUMEN
Direct ethanol fuel cells have great potential for practical power applications due to their easy operation, high energy density, and low toxicity. However, the slow and incomplete ethanol electrooxidation (EEO) reaction is a major drawback that hinders the development of this type of fuel cell. Here, we report a facile approach for the preparation of highly active, low cost and stable electrocatalysts based on palladium (Pd) nanoparticles and black phosphorus/palladium (BP/Pd) nanohybrids supported on a carbon aerogel (CA). The nanocomposites show remarkable catalytic performance and stability as anode electrocatalysts for EEO in an alkaline medium. A mass peak current density of 8376 mA mgPd -1 is attained for EEO on the BP/Pd/CA catalyst, which is 11.4 times higher than that of the commercial Pd/C catalyst. To gain deep insight into the structure-property relationship associated with superior electroactivity, the catalysts are well characterized in terms of morphology, surface chemistry, and catalytic activity. It is found that the BP-doped CA support provides high catalyst dispersibility, protection against leaching, and modification of the electronic and catalytic properties of Pd, while the catalyst modifies CA into a more open and conductive structure. This synergistic interaction between the support and the catalyst improves the transport of active species and electrons at the electrode/electrolyte interface, leading to rapid EEO reaction kinetics.
RESUMEN
Impulsive light excitation presents a powerful tool for investigating the interdependent structural and electronic responses in layered two-dimensional (2D) halide perovskites. However, detailed understanding of the nonlinear lattice dynamics in these soft hybrid materials remains limited. Here, we explicate the intrinsic strain propagation mechanisms in 2D perovskite single crystals using transient reflection spectroscopy. Ultrafast photoexcitation leads to the generation of strain pulses via thermoelastic (TE) stress and deformation potential (DP) interaction whence their detection proceed via Brillouin scattering. Using a two-temperature model together with strain wave propagation, we discern the TE and DP contributions in strain generation. Hot carrier cooling plays a dominant role in effecting the weak modulation amplitude. Out-of-plane lattice stiffness is reduced by the weak van der Waals bond between organic layers, resulting in a slow strain propagation velocity. Our findings inject fresh insights into the basic strain properties of layered perovskites critical for manipulating their functional properties for new applications.
RESUMEN
Host response to COVID-19 vaccines is partially evaluated through the estimation of antibody response, specifically the binding anti-spike (anti-S) and the neutralizing antibodies (nAbs) against SARS-CoV-2. Vaccine-induced humoral response affects decisions on the choice of vaccine type, vaccine acceptance, and the need for boosting. Identification of risk factors for poor antibody response helps to stratify individuals who might potentially require booster doses. The primary objective of this cross-sectional study was to investigate the antibody response after receiving two Sinopharm vaccine doses. Factors affecting antibody response were additionally studied. Moreover, a predictive cutoff for anti-S was generated to predict positivity of nAbs. Blood samples were collected from 92 adults and relevant data were recorded. Antibody levels (anti-S and nAbs) against SARS-CoV-2 were tested one month following the second dose of Sinopharm vaccine using two commercial ELISA tests. Among the 92 participants, 88 tested positive for anti-S (95.7%), with a median level of 52.15 RU/mL (equivalent to 166.88 BAU/mL). Fewer participants (67.4%) were positive for nAbs, with a median percentage of inhibition (%IH) of 50.62% (24.05−84.36). A significant positive correlation existed between the titers of both antibodies (correlation coefficient = 0.875, p < 0.001). When the anti-S titer was greater than 40 RU/mL (128 BAU/mL), nAbs were also positive with a sensitivity of 80.6% and a specificity of 90%. Positive nAbs results were associated with a higher anti-S titers (62.1 RU/mL) compared to negative nAbs (mean anti-S titer of 18.6 RU/mL). History of COVID-19 infection was significantly associated with higher titers of anti-S (p = 0.043) and higher IH% of nAbs (p = 0.048). Hypertensive participants were found to have significantly higher median titers of anti-S (101.18 RU/mL) compared with non-hypertensive ones (42.15 RU/mL), p = 0.034. Post-vaccination headache was significantly higher among those with higher anti-S than those with relatively lower titers (98.82 versus 43.69 RU/mL, p = 0.048). It can be concluded that the Sinopharm vaccine produced high levels of binding antibodies but with low neutralizing abilities. Also, levels of anti-S titer greater than 40 RU/mL could adequately predict positivity of nAbs without need for their testing.
RESUMEN
Using high-throughput first-principles calculations to search for layered van der Waals materials with the largest piezoelectric stress coefficients, we discover NbOI2 to be the one among 2940 monolayers screened. The piezoelectric performance of NbOI2 is independent of thickness, and its electromechanical coupling factor of near unity is a hallmark of optimal interconversion between electrical and mechanical energy. Laser scanning vibrometer studies on bulk and few-layer NbOI2 crystals verify their huge piezoelectric responses, which exceed internal references such as In2Se3 and CuInP2S6. Furthermore, we provide insights into the atomic origins of anti-correlated piezoelectric and ferroelectric responses in NbOX2 (X = Cl, Br, I), based on bond covalency and structural distortions in these materials. Our discovery that NbOI2 has the largest piezoelectric stress coefficients among 2D materials calls for the development of NbOI2-based flexible nanoscale piezoelectric devices.
RESUMEN
Noninvasive imaging of the atomic arrangement in two-dimensional (2D) Ruddlesden-Popper hybrid perovskites (RPPs) is challenging because of the insulating nature and softness of the organic layers. Here, we demonstrate a sub-angstrom resolution imaging of both soft organic layers and inorganic framework in a prototypical 2D lead-halide RPP crystal via combined tip-functionalized scanning tunneling microscopy (STM) and noncontact atomic force microscopy (ncAFM) corroborated by theoretical simulations. STM measurements unveil the atomic reconstruction of the inorganic lead-halide lattice and overall twin-domain composition of the RPP crystal, while ncAFM measurements with a CO-tip enable nonperturbative visualization of the cooperative reordering of surface organic cations driven by their hydrogen bonding interactions with the inorganic lattice. Moreover, such a joint technique also allows for the atomic-scale imaging of the electrostatic potential variation across the twin-domain walls, revealing alternating quasi-1D electron and hole channels at neighboring twin boundaries, which may influence in-plane exciton transport and dissociation.
RESUMEN
Molecularly soft organic-inorganic hybrid perovskites are susceptible to dynamic instabilities of the lattice called octahedral tilt, which directly impacts their carrier transport and exciton-phonon coupling. Although the structural phase transitions associated with octahedral tilt has been extensively studied in 3D hybrid halide perovskites, its impact in hybrid 2D perovskites is not well understood. Here, we used scanning tunneling microscopy (STM) to directly visualize surface octahedral tilt in freshly exfoliated 2D Ruddlesden-Popper perovskites (RPPs) across the homologous series, whereby the steric hindrance imposed by long organic cations is unlocked by exfoliation. The experimentally determined octahedral tilts from n = 1 to n = 4 RPPs from STM images are found to agree very well with out-of-plane surface octahedral tilts predicted by density functional theory calculations. The surface-enhanced octahedral tilt is correlated to excitonic redshift observed in photoluminescence (PL), and it enhances inversion asymmetry normal to the direction of quantum well and promotes Rashba spin splitting for n > 1.
RESUMEN
Liquid-phase exfoliation can be developed for the large-scale production of two-dimensional materials for photonic applications. Although atomically thin 2D transition metal dichalcogenides (TMDs) show enhanced nonlinear optical properties or photoluminescence quantum yield relative to the bulk phase, these properties are weak in the absolute sense due to the ultrashort optical path, and they are also sensitive to layer-dependent symmetry properties. Another practical issue is that the chemical stability of some TMDs (e.g., Weyl semimetals) decreases dramatically as the thickness scales down to monolayer, precluding application as optical components in air. To address these issues, a way of exfoliating TMDs that ensures instantaneous passivation needs to be developed. Here, we employed a polymer-assisted electrochemical exfoliation strategy to synthesize PVP-passivated TMDs monolayers that could be spin coated and restacked into organic-inorganic superlattices with well-defined X-ray diffraction patterns. The segregation of restacked TMDs (e.g., MoS2) by PVP allows the inversion asymmetry of individual layers to be maintained in these superlattices, which allows second harmonic generation and photoluminescence to be linearly scaled with thickness. PVP-passivated monolayer 1T'-MoTe2 saturable absorber fabricated from these flakes exhibits fast response and recovery time (<150 fs) and pulse stability. Continuous-wave mode-locking based on 1T'-MoTe2 saturable absorber in a fiber ring laser cavity has been realized, attaining a fundamental repetition rate of 3.15 MHz and pulse duration as short as 867 fs at 1563 nm.