Metal halide perovskite semiconductors have demonstrated remarkable potentials in solution‐processed blue light‐emitting diodes (LEDs). However, the unsatisfied efficiency and spectral stability ...responsible for trap‐mediated non‐radiative losses and halide phase segregation remain the primary unsolved challenges for blue perovskite LEDs. In this study, it is reported that a fluorene‐based π‐conjugated cationic polymer can be blended with the perovskite semiconductor to control film formation and optoelectronic properties. As a result, sky‐blue and true‐blue perovskite LEDs with Commission Internationale de l'Eclairage coordinates of (0.08, 0.22) and (0.12, 0.13) at the record external quantum efficiencies of 11.2% and 8.0% were achieved. In addition, the mixed halide perovskites with the conjugated cationic polymer exhibit excellent spectral stability under external bias. This result illustrates that π‐conjugated cationic polymers have a great potential to realize efficient blue mixed‐halide perovskite LEDs with stable electroluminescence.
A fluorene‐based π‐conjugated cationic polymer as a multifunctional passivator to suppress non‐radiative processes, improve charge transport properties, and inhibit ion migration for blue mixed‐halide perovskite semiconductors, is reported. As a result, efficient and spectrally stable blue perovskite light‐emitting diodes with emission wavelengths from 485 to 458 nm are achieved.
This study highlights the effects of industry collaboration in enhancing academic innovation output. We exploit a unique longitudinal dataset on the 110 top U.S. research universities for the last ...19years. Our empirical findings confirm that the relationship between the number of industry collaborations and academic innovation is curvilinear. Moreover, we hypothesized and found that university contribution, collaboration breadth and knowledge capacity moderate the curvilinear relationship between the number of industry collaborations and academic innovation. Poisson, negative binomial and generalized negative binomial regressions are used to test the hypotheses in a panel data of 2090 university-year cases. Our results are robust to the three econometric methods, measures of variety of academic innovation and the findings support our prediction.
•Factors related to academic innovation are identified.•The number of industry collaborations has a curvilinear relationship with academic innovation.•University contribution strengthens the benefits and lessens the costs of collaborations.•Industry collaborations also depend on collaboration breadth and knowledge capacity.
The purpose of this paper is to contribute to the limited research on universities' decision to innovate, using the network and knowledge-based perspectives as our theoretical underpinning. The first ...conclusion is that universities are more likely to locate their scientific productivity on a standalone campus than in a multi-campus system when the knowledge effect is more favorable. To make a contribution to industry and collaboration, universities are more likely to locate their scientific productivity in a multi-campus system. The second conclusion is that after controlling for endogeneity bias, the mean of academic performance for scientific productivity on a standalone campus is higher than it is on a multi-campus system. The third conclusion is that locating innovation activities in either a standalone or multi-campus system under theoretically appropriate conditions increases academic performance. These findings pose interesting challenges for knowledge management in innovation through a university's location decision.
Although one school of thought in the university-industry interactive literature is that universities learn from prior collaboration, we posit that any potential knowledge learning effects depend on ...the type of collaboration. Our empirical findings confirm that the use of collaboration exploitation, exploration and balancing strategy of ambidexterity all improve a university’s innovation. We also posit that proactive searching allows universities to leverage their collaboration exploitation and exploration. In contrast, when universities combine ambidexterity with a proactive search strategy, the negative consequences for university innovation become more pronounced. To test this integrative model of U-I collaboration, we leverage a unique and detailed longitudinal dataset on the 110 top U.S. research universities and the top 200 R&D performing firms to account for a large share of research papers published in the U.S. in the last 19 years. Poisson and negative binomial regression models are used to test the hypotheses in panel data of 2090 university-year cases. We find support for our theoretical model.
Functional passivators are conventionally utilized in modifying the crystallization properties of perovskites to minimize the non‐radiative recombination losses in perovskite light‐emitting diodes ...(PeLEDs). However, the weak anchor ability of some commonly adopted molecules has limited passivation ability to perovskites and even may desorb from the passivated defects in a short period of time, which bring about plenty of challenges for further development of high‐performance PeLEDs. Here, a multidentate molecule, formamidine sulfinic acid (FSA), is introduced as a novel passivator to perovskites. FSA has multifunctional groups (S≐O, C≐N and NH2) where the S≐O and C≐N groups enable coordination with the lead ions and the NH2 interacts with the bromide ions, thus providing the most effective chemical passivation for defects and in turn the formation of highly stable perovskite emitters. Moreover, the interaction between the FSA and octahedral PbBr64− can inhibit the formation of unfavorable low‐n domains to further minimize the inefficient energy transfer inside the perovskite emitters. Therefore, the FSA passivated green‐emitting PeLED exhibits a high external quantum efficiency (EQE) of 26.5% with fourfold enhancement in operating lifetime as compared to the control device, consolidating that the multidentate molecule is a promising strategy to effectively and sustainably passivate the perovskites.
A multidentate molecule (Formamidine Sulfinic Acid, FSA) to passivate the perovskite for efficient light‐emitting devices. Owing to its multiple roles of guaranteeing sufficient passivation durability and minimizing the energy loss, green PeLEDs based on the FSA‐perovskite films shows a superior EQE of 26.5%.
Although corporate venture capital (CVC) is a potential source of innovation, few studies have directly examined the impact of a parent company’s knowledge and resources on a new venture firm’s ...innovation performance. This article investigates the impact of experience with parent’s alliance and investment intensity on the extent to which new ventures in the U.S. use their parents’ knowledge and financial resources for their innovation activities at the inception of the CVC relationship over a 44-year period. Our findings suggest that ventures with alliance experience draw more on collaboration knowledge and relational capital, while investment intensity also increases innovation. At a low level of investment complexity, the use of alliance experience and investment intensity is positively related to innovation performance. However, when a parent company has high investment complexity for innovation performance, investment intensity and alliance experience are less effective. Our results, thus, unveil the CVC backing associated with the innovation of new venture firms.
Purpose
How does university-firm collaboration affect the performance of both universities and firms? The purpose of this paper is to evaluate university-firm collaborations aimed at expanding the ...treatment effects of collaboration ambition on university academic performance as well as collaboration ambition focused on the firm’s production of innovation and financial performance for the top 110 US universities and the top 200 US R&D performing firms.
Design/methodology/approach
“Two studies, based on the three archival data sets (National Bureau of Economic Research-Rensselaer Scientific Papers Database and the Harvard Dataverse Network (DVN) US Patent Citations database and Compustat database), are undertaken in the top 110 US universities and the top 200 US R&D performing firms.” The study introduces a theoretical model that explicitly addresses collaboration diversity, number of collaborations, knowledge stock and the endogeneity problem that is generated by self-selection of collaboration ambition in university and firm’s performance.
Findings
The results suggest that the effects of adopting proactive collaboration decision on academic performance are insignificant in the firm subsample. However, more interestingly, the authors find supporting evidence of the negative impact of collaboration on university groups. The authors also find that collaboration diversity, knowledge stock and collaboration ambition lead to stronger firm performance but the number of collaborations is smaller on firm performance. Furthermore, the authors find that collaboration ambition moderates the positive effect of the number of collaborations on firm performance.
Practical implications
University-firm collaboration is a multifaceted relationship, suggesting that the empirical analysis can be interpreted through the university and the firm view to enhance the understanding of the collaboration for performance creation. This study articulates the positive role of collaboration diversity, knowledge stock and collaboration ambition and the negative role of the number of collaborations on university-firm collaboration in terms of university and firm performance. Moreover, proactive collaboration ambition has the positive effect of a higher number of collaborations on firm performance. The authors conclude that policy should refrain from overly focusing on collaboration diversity, number of collaborations, knowledge stock and collaboration ambition, and the authors consider the interactions between the number of collaborations and collaboration ambition on university-firm collaboration when discussing their effects on mutual performance.
Originality/value
This study demonstrates the effects of university-firm collaboration on academic performance. In addition, the authors discuss the factors that influence collaboration to help the firm to increase its innovation and financial performance. Therefore, it would be interesting to see simultaneously how university-firm collaboration affects the performance of both partners.
Abstract
How is joint ventures' (JVs) innovation performance affected by their parent companies' equity investment and their exploitation of their parent firms' knowledge? We investigate 183 JV cases ...and examine the main effect of equity investment as well as the moderating effect of ambidexterity imbalance on the relationship between JVs' knowledge exploitation and exploration of their innovation performance. We utilize proprietary Securities Data Corporation (SDC) JV data combined with the National Bureau of Economic Research's (NBER) patent dataset to develop a mediated moderation model. The model indicates that equity investment is positively related to knowledge exploitation, which in turn has a positive effect on JVs' innovation; in addition, these relationships vary alongside ambidexterity imbalance. Our findings confirm the mediating role played by knowledge exploitation in JVs' innovative activities and highlight the tradeoff between organizational ambidexterity balance and knowledge exploitation as well as its influence on JVs' innovation performance. This research illuminates the foundations of JV innovation. Managerial implications are also discussed.
Previous research has underscored the significance of the equity investment relationship in facilitating knowledge transfers between a joint venture and its parent company. Successful knowledge ...bridging in joint ventures plays a crucial role in shaping organizational learning and innovation performance outcomes. The empirical evidence on the effectiveness of knowledge transfers, however, presents a mixed picture. Through a rigorous sample selection process, we collect panel data on 366 joint venture-year observations across four industries during an 18-year period to empirically test the proposed hypotheses. In this research, we contend that the ability of joint ventures to act as knowledge bridges depends on the diversity of the parent's knowledge and the technological similarity between the joint venture and the parent, especially in the context of internal knowledge development. An examination of bridging performance in the relationship between joint ventures and parent companies indicates that both parental knowledge diversity and joint venture - parent technology similarity positively impact the knowledge acquired through the joint venture - parent equity relationship. Furthermore, when the joint venture strongly depends on internal knowledge, the positive relationship among parental knowledge diversity, joint venture - parent technology similarity, and joint venture knowledge bridging becomes more pronounced. Our findings shed light on how the specific features of a parent company contribute to the knowledge learning bridged by a joint venture and underscore the role of equity investments in joint venture firms' innovation.
Mechanical grinding combined flotation technology with renewable collector has been proposed to recover high-grade copper from waste printed circuit boards (WPCBs). Surface morphology and element ...distribution of copper particle section were analyzed using scanning electron microscopy and energy dispersive spectrometry (SEM + EDS) technology. Results show that the copper particle is covered with a layer of micrometer-scale organic matter. Thermogravimetric analysis demonstrates the organic layer commonly existed on all of the particle surfaces, which prove that the pyrolysis method was not feasible for selectively removing the organic impurity. Mechanical grinding pretreatment was proposed to peel off the organic layer. Grinding experiment results show that impurity can be effectively separated from copper. Soap collector prepared from waste oil was used for flotation. The flotation results show that the copper grade of the concentrate first increased and then decreased with the increase of the grinding time, while the recovery gradually decreased from 78.7% to 21.7%. Concentrate with 79.1% copper grade and 71.5% recovery was obtained when the grinding time was 3 min. This study provides a physical approach to recover high-grade copper from WPCBs.
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•Grinding-assistant was used to improve copper grade in flotation concentrate.•Copper concentrate with 79.06% grade was obtained from e-waste.•Collectors prepared from waste oils are successfully used in flotation of e-waste.
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