Last June, Benedetto Vigna became the new CEO of Ferrari NV, joining the company from semiconductor manufacturer STMicroelectronics NV. The chairman of Ferrari noted Vigna’s “deep understanding of the technologies driving much of the change in our industry,” and the subsequent press release stressed Vigna’s experience “at the heart of the semiconductor industry that is rapidly transforming the automotive sector.” The emphasis on the new CEO’s technological background was emblematic of an important yet underexplored development: the growing impact of technological expertise on the executive labor market. In a new paper, we examine whether the degree to which companies share an expertise in technology drives competition for managers and, hence, compensation. Our focus is based on the notion that firms with similar technologies are likely to value similar managerial attributes. As CEOs gain experience with and knowledge of the businesses they run, they are also likely to gain expertise in technological domains associated with managing firms in certain technological areas. Therefore, managers’ expertise in certain technological domains is valuable not only to their firm but also to other firms that focus on similar technology. This will ultimately be manifested in CEO compensation policies. Studies show that a manager’s technological expertise plays an important role in determining how much the manager and his firm complement each other. Our focus on the role of technological-expertise similarities in shaping firms’ compensation policies is also consistent with how many proxy statements treat technological considerations as important in choosing peer groups for benchmarking executive compensation. We use patent technology classifications to measure firms’ technological expertise and their similarities. Using compensation-benchmarking peer-firm data and the technological overlap measure, we begin by showing that similarity in technological expertise is a significant determinant of whether a certain firm is used as a compensation benchmarking peer. Moreover, even within the same industry and size groups, we show that a firm’s choice of peer firms is determined by its technological similarity to those firms. Our results suggest that technological similarity plays a crucial role in firms’ choice of peer group and that considering the role of technological fit is critical for demonstrating the efficiency of the labor market and the composition of the peer group. We then present evidence consistent with compensation benchmarking being an efficient approach to estimating the market wage for human capital, as opposed to its use reflecting managerial opportunism. We show that higher technological similarity with benchmarking peer firms increases the likelihood that a CEO who received above-median (below-median) pay in the previous year received at or below-median (above-median) pay in the following year. This result is obtained even after controlling for other important compensation determinants from previous studies, and is consistent with the market-based theory of CEO compensation in that firms set CEO pay to remain competitive with firms that are competing for similar managerial talent. After establishing that technological similarity has an important effect on CEO compensation benchmarking patterns, we provide evidence that its use reflects CEOs’ outside options. In particular, we show that an increase in technological similarity increases the likelihood of the CEO joining a similar firm. Our finding reflects the notion that the marketability of CEOs’ technological expertise is at least partly reflected in firms’ technological similarity and that firms prefer to hire CEOs with a better technological fit. Furthermore, we show that the CEO compensation levels of technologically similar peer firms are positively associated with CEO pay at the focal firm. We thus provide evidence that technological similarity plays a crucial role in the market for CEO talent and that the labor market consistently reflects CEOs’ outside opportunities. Overall, our study contributes to the literature focusing on the effect of similarities in technological expertise on corporate policies, shows that technological expertise is a distinct and previously overlooked aspect of transferable CEO skill, adds to the literature on optimal contracting for CEO compensation, and shows that technological similarity plays an important role in determining compensation benchmarking peers – consistent with an efficient contracting motivation. This paper is forthcoming in the one of the leading journals in the finance field, the Journal of Financial and Quantitative Analysis, and is available at the following link: https://doi.org/10.1017/S0022109022000229
Professor Seyoung Park in the department of Statistics recently proposed the novel clustering method by integrating multi-dimensional data for clustering analysis. Advances in high-throughput genomic technologies coupled with large-scale study projects have generated rich resources of diverse types of omics data to better understand disease etiology and treatment responses. Clustering patients into subtypes with similar disease etiologies and/or treatment responses using multiple omics data has the potential to improve the precision of clustering than using a single type of omics data. However, in practice patient clustering is still mostly based on a single omics data type or ad hoc integration of clustering results from each data type, leading to potential loss of information. By treating each omic data type as a different informative representation from patients, this research proposes a novel multi-view spectral clustering framework to integrate different omics data types measured from the same subject. The proposed method learns the weight of each data type as well as a similarity measure between patients via a non-convex optimization framework. When the proposed method is applied to the TCGA data, the patient clusters inferred by the proposed method show more significant differences in survival times between clusters than those between clusters inferred from existing clustering methods. Professor Park said “The main contribution of this research is to conduct clustering analysis using multiple high-dimensional data by considering the heterogeneity of different data and learning importance of data. We expect to apply the same idea to the different statistical frameworks using multiple high-dimensional data. “ This research is published in the “Journal of the American Statistical Association”, which is the top journal in Statistics. ※ Title: Integrating multidimensional data for clustering analysis with applications to cancer patient data ※ Source: https://doi.org/10.1080/01621459.2020.1730853
The research team* of Professor Yunseok Kim demonstrates a way to highly enhance the ferroelectricity of HfO2-based ferroelectrics using ion bombardment. * Co-corresponding authors: Prof. Young-Min Kim (SKKU), Dr. Jinseung Heo (Samsung Advanced Institute of Technology), Dr. Sergei Kalinin (Oak Ridge National Laboratory, USA) Continuous advancement in nonvolatile and morphotropic beyond-Moore electronic devices necessitates the development of strategies that utilize the wealth of functionalities of complex materials at extremely reduced dimensions. The discovery of ferroelectricity in hafnium oxide (HfO2)–based ferroelectrics that are compatible with the semiconductor process has opened interesting and promising avenues of research. However, the origins of ferroelectricity and pathways to controlling it in HfO2-based ferroelectrics are still mysterious. We report that local ion bombardment can activate ferroelectricity in these materials. The possible competing mechanisms, including ion-induced molar volume changes, vacancy redistribution, vacancy generation, and activation of vacancy mobility, are discussed. These findings including the variation of ferroelectricity through defect engineering based on ion bombardment suggest additional possibilities for ferroelectricity enhancement in HfO2-based ferroelectrics. Furthermore, this approach can be directly applied to a semiconductor process without structural modification and, thus, can increase its applicability in next-generation electronic devices, such as ultra-scaled ferroelectrics-based transistors and memories. [Paper] - “Highly enhanced ferroelectricity in HfO2-based ferroelectric thin film by light ion bombardment”, Science 376(6594), 731-738 (2022) - URL: https://www.science.org/doi/10.1126/science.abk3195 □ Webpage: http://spm.skku.edu
On April 22, 'Over 30% efficient indoor organic photovoltaics enabled by morphological modification using two compatible non-fullerene acceptors' written by Professor Doo-Hyun Ko's research party was recognized for excellent research and was published in 'Advanced Energy Materials (IF=29.368)', a world-renowned academic journal. Professor Ko’s research party demonstrated an indoor organic photovoltaic cell that achieves power conversion efficiency exceeding 30% by introducing an organic photoactive layer that enables efficiently harvesting the photons under the indoor environment of low irradiance. The research results of the high-performance indoor organic photovoltaic cells are expected to be utilized in the indoor Internet of Things and smart-farm fields that require a continuous power supply. The photovoltaic efficiency is determined by effectively extracting the charge carriers, generated inside the photoactive layer of the photovoltaic cell, toward the electrode without recombination loss. Notably, under indoor lighting in which intensities are 10-100 times lower relative to the sunlight, charge carrier loss significantly contributes to a decrease in the power conversion efficiency. In this study, the photoactive layer was fabricated by blending two well-miscible non-fullerene acceptors and polymer donors. The introduced photoactive layer features nanoscale phase separation between donor and acceptor with high para-crystallinity. Through these separated donor and acceptor phases, the positive (hole) and negative charge (electron) carriers can be transported toward the electrode without recombination loss, respectively. Thereby, the organic photovoltaic cells reported by Professor Ko’s research party achieved a power conversion efficiency of over 30% under indoor circumstances of low irradiance by fabricating the superior photoactive layer. Participating researchers and authors: Chihyung Lee (co-first author, SKKU, Ph.D. candidate), Jung-Hyun Lee (co-first author, SKKU, master course), Hyun Hwi Lee (second author, Pohang Accelerator Research Institute, researcher), Minwoo Nam (corresponding author, Sangji University, assistant professor), Doo-Hyun Ko (corresponding author, SKKU, associate professor). [Figure 1] (a) Image of organic photovoltaic under low light conditions. (b) AFM image of donor and acceptor phase separation through morphology controlling photoactive layer. (c) J-V characteristics of organic photovoltaic under low light environment (250, 500, and 1000 lux 3000 K LED)
SKKU School of Chemical Engineering Professor Tae-il Kim’s research team, led by Dr. Byeong-hak Park, succeeded in developing a damping material that selectively removes external noise by mimicking the pad of a spider’s leg and an electronic device using it. Recently, bioelectronic devices, including commercially available smartwatches and smartphones, measure important bio-signals in the form of being attached to or inserted into the body. A lot of research has been done to improve device performance for more precise measurement, but as the device performance increases, there is a problem in that when measuring biological signals, interference from various biological signals, including unconscious noise, makes it difficult to distinguish signals. In particular, general noises such as simple walking and movement have a band of less than 30 Hz and are inevitably one of the factors that obstruct the collection of bio-signals. In the current research stage to reduce noise, including commercialized electronic devices, signal processing technology, and machine learning-based signal classification using the same are heavily concentrated. However, this causes signal distortion, requires additional circuitry, and has disadvantages in that it is difficult to change the signal band immediately. In addition, other damping materials have a problem in that they are not optimized for selective bio-signal collection. Therefore, there is a need for a material that passes a bio-signal having a relatively high-frequency band and selectively damps noises having a low-frequency band. Therefore, the research team tried to solve the above problems with inspiration from natural materials. In the case of spiders, they have very sensitive vibration receptors, so they can sensitively receive vibration signals from enemies, prey, or mates. In particular, the signal can be read well even from external noise such as wind or rain, because the viscoelastic pad located in front of the vibration receptor selectively damps the low-frequency signal. Based on this, the research team produced a gelatin/chitosan-based viscoelastic hydrogel by simulating the principle of a spider’s pad. In the case of the spider’s pad, it is hypothesized that chitin is composed of a sugar and protein, and in the case of chitin, many hydrogen bonds are formed between adjacent polymer chains, and in the case of proteins, it is hypothesized that a phase change is induced between the chains. In fact, it was confirmed that the gelatin/chitosan-based viscoelastic hydrogel had higher damping energy and selectivity than other damping materials. In addition, it was confirmed that the damping range can be adjusted in real-time from about 1 Hz to 50 Hz when the temperature is externally controlled to 45 degrees. Using this, combined with a strain sensor, mechanical bio-signals such as neck vibration and heart rate can be read with a high signal-to-noise ratio under noise, and electrical bio-signals such as electrocardiogram and brainwaves can also be stably detected under noise. By using signal processing to obtain a higher signal-to-noise ratio than the existing method that removes noise, it has been proven that the material selectively damping the noise is much more effective than the existing method. Professor Tae-il Kim said, “This study is a case of materially solving the chronic noise problem of existing electronic devices by mimicking the special mechanical properties of spiders in nature. Selectively reducing external noise can be a more effective method of collecting bio-signals.” In addition, he explained the significance of the study and follow-up research plans. Saying, “by minimizing noise, bio-signal monitoring research has been activated, and it is expected that sensitive signals that were difficult to obtain in real-time will be read out and be of great use in diagnosis and biomedical engineering.” (Image 1) Selective noise damping in a spider's cuticular pad and the bioinspired gelatin-chitosan hydrogel damper for selective frequency-dependent damping (Image 2) Demonstration of dynamic noise-damping by using the hydrogel damper for high SNR detection of biophysiological signals
Prof. Jae Do Nam's research team (Functional nanocomposite lab., first author Uiseok Hwang) developed polymer-based composites with frequency-selective electromagnetic shielding (EMI) capabilities and presented a new breakthrough in aerospace material technologies such as stealth aircraft, satellites, etc. Recently, as various electromagnetic (EM) waves exist over a broad frequency spectrum generated from electronic devices, autonomous vehicles, and 5G communication, there is a need for a material capable of selectively shielding EM waves of the desired frequency range. Unfortunately, such technology has rarely been reported because most EMI shielding materials exhibit low-frequency selectivity. The research team found that when spherical particles with wave-reflecting and -absorbing abilities are mixed and applied as polymer-based composites, EM waves in different frequency ranges can be selectively absorbed depending on their mixing ratio and arrangement in the matrix. The composite materials presented in this study can be used as Radar Absorbing Materials (RAMs) for stealth aircraft. The materials can selectively shield the undesirable EM waves in enemy radar frequency ranges and transmit them in telecommunication frequency ranges, enabling the pilots to smoothly communicate without device malfunction and detection from the enemy. This work was supported by projects from the U.S. Air Force Office of Scientific Research/AOARD and Center for Composite Materials & Concurrent Design (Director Prof. Jonghwan Suhr) and published as a front cover in the Journal of Materials Chemistry A (IF: 12.732), a prominent international journal in the field of materials research. [Research Overview] Aperture control in polymer-based composites and frequency-selective EM wave absorption characteristics [Journal Front Cover] ※ Title: Aperture control in polymer-based composites with hybrid core-shell spheres for frequency-selective electromagnetic interference shielding ※ DOI: https://doi.org/10.1039/D2TA00045H
Professor Dong Seong (Don) Lee’s (Graduate School of Governance / Department of Public Administration)'s research introduced in the Washington Post Professor Lee has published a co-authored article in COMPARATIVE POLITICAL STUDIES (ranked top 8% among SSCI journals), titled “Breaking the Cabinet’s Glass Ceiling: The Gendered Effect of Political Experience in Presidential Democracies. The research examines whether women face discrimination in their political careers after their initial cabinet appointment. With new data on the careers of all 1,374 ministers who have held office in the major presidential democracies in Asia, including the 515 ministers who have served in Korea since the 1988 democratization, he tests for gendered patterns in “cabinet promotions”—instances where a president approves the transfer of a minister from their initial appointment to a higher-prestige executive post, one with access to greater power and financial resources. Overall, the results show that male and female cabinet ministers experience surprisingly similar promotion rates. At first glance, this may indicate that most gender discrimination occurs at the appointment stage and that afterward, there is more gender parity. However, while the overall promotion rates may be similar across genders, there are significant differential effects of political experience on the likelihood of men and women receiving a promotion. For female ministers, having a political background increases the chance of promotion by 17 percentage points more than it does for male ministers. The political experience thus matters much more for women’s upward mobility in cabinets than men. This research was introduced in the Washington Post (Post) as an article titled “South Korea’s new leader says there’s no gender inequality problem,” which links to the Post’s recent interview with South Korea’s president-elect, Yoon Suk-yeol. According to the article posted in the Post, in contrast to Yoon’s assertion that systemic gender inequality is “a thing of the past” in his country, significant gender discrimination exists in presidential cabinets in South Korea, as shown by Professor Lee’s research findings. The Post’s article concludes that the South Korean cabinets may become more balanced over time as more women gain cabinet positions. But that will be only feasible when presidents place more excellent value on having a gender balance in their cabinet and empowering gateway ministries, such as a women’s affairs ministry, to help more women initiate and build their cabinet careers.
Due to the industrial revolution using coal in the mid-18th century and the discovery of crude oil in the 19th century, humankind has made rapid progress by developing technologies to mass-produce cheap fuels and chemicals. Korea also ranks 5th in the world for its heavy chemical industry development strategy in the 1970s and has the 8th largest oil refining industry in the world.In the 20th century, rapid economic development was achieve globally through the use of fossil fuels such as crude oil and coal, but as a reward, the concentration of CO2 in the atmosphere increased day by day and reached 420 ppm. It has reached a stage that threatens the survival of humankind, such as global warming, ecosystem destruction, sea-level rise and seawater acidification. ProfessorJae-Hoon Kim's research team (Department of Mechanical Engineering) at Sungkyunkwan University has developed a technology that can selectively produce fuels and value-added chemicals by reacting carbon dioxide emitted from industry with renewable hydrogen. The research is expected to contribute to mitigating climate change. The research team developed a technology for synthesizing C5+ long-chain hydrocarbons that can be used as fuel for gasoline and diesel with high selectivity of 77.0% from CO2 using an iron-based catalyst (Na-FeAlOx) with an alumina promoter. The results were published in ACS Catalysis at 2020 [ACS Catalysis, 2020, 10, 10325−10338]. Through this study, the research team identified the principle of the synthesis mechanism of alpha-olefin, a precursor of aromatic compounds, in iron-based catalysts. [Reaction mechanism of CO2 in the Na-FeAlOx catalyst] The research team confirmed that it was possible to produce aromatic compounds from carbon dioxide with a high CO2 conversion rate of 45% and a high aromatic selectivity of 39% by using a composite catalyst combining iron-based catalyst and zeolite. The results were published in Applied Catalysis B:Environmental at 2022 [Applied Catalysis B: Environmental, 2022, 301, 120813]. In particular, the selectivity of BTX among aromatic compounds was high at 59% by controlling the acid site of zeolite. The highly value-added aromatic compound refers to benzene, toluene, xylene, etc. These essential chemical materials rank first in total petro chemical production. [Na-FeAlOx/zeolite Synthesis of aromatic compounds directly from CO2 in complex catalysts] In addition, the research team developed the world's first process that can operate for over 1425 hours with a high yield of about 20% of C5+ long-chain hydrocarbons from CO2 using a cobalt-based catalyst. The results were published in Applied Catalysis B: Environmental at 2022 [AppliedCatalysis B: Environmental, 2022, 305, 121041]. Furthermore, the cobalt-based catalyst newly developed by the research team laid the foundation for the production of promising liquid fuels and lube base oils because the catalysts exhibit high C5+ and C21+ selectivity in the conversion of CO2. In addition, the research team designed a nickel-zinc alloy catalyst capable of synthesizing high value-added chemical materials such as acetic acid and propionic acid by direct hydrogenation of CO2, and published the results in ACS Catalysis at 2021 [ACS Catalysis, 2021, 11,8382–8398]. [Mechanism of direct long-chain hydrocarbon synthesis from CO2 using Na-CoMnOxcatalyst] Currently,Professor Jae-Hoon Kim's research team is researching the possibility ofcommercialization in collaboration with a domestic oil refinery. It intends tocontribute to reducing national greenhouse gases in the future.
In collaboration with Professor Dong-Hwan Kim (School of Chemical Engineering), Professor Dae Joon Kang (Department of Physics)'s team has reported a novel approach to increase polydimethylsiloxane-based output power density flexible triboelectric nanogenerators using ultra-thin nickel telluride nanosheets as a co-triboelectric layer. Flexible triboelectric nanogenerators (FTENGs) can harness various mechanical energies such as wind, water flow, and human motion for energy and sensing purposes; therefore, it was in the spotlight. In general, a critical factor that determines the electrical output behavior of FTENGs is the proper selection of active triboelectric materials. Among the many suitable triboelectric materials, polydimethylsiloxane (PDMS) is considered an excellent material for FTENGs due to its good mechanical strength, high flexibility, and excellent electron negativity. However, the output power density of PDMS-based FTENGs remains unsatisfactory. Inorganic materials such as metal sulfides, semiconductingmetal oxides, metal-organic frameworks, and MXenes could be explored as activeco-triboelectric materials in combination with PDMS due to their high chemicalstability, excellent mechanical strength, and high electrical conductivity.Among the many novel inorganic materials, nickel telluride (NiTe2) is considered a promising co-triboelectric material with PDMS due to its goodconductivity, high chemical stability, good mechanical strength, and facilesynthesis. Moreover, highly conductive NiTe2 can effectively lower the internalresistance of PDMS, further improving the output performance of PDMS-basedFTENGs. In addition, the nano-belt (NB) can be considered a promising platformfor designing high-performance energy collection devices due to its uniquemorphological advantages of higher aspect ratio, larger surface area, moreenergy collection sites, and faster charge transfer rate compared to many otherform factors. Therefore, the team used NiTe2 NBs as a co-triboelectric material with PDMS to further improve the output performance of PDMS-based FTENGs. The team systematically investigated their triboelectric performance in terms of the weight ratio of NiTe2 NB to PDMS, the device's size, the thickness of PDMS, and the temperature dependence of their output power. As a result, the optimized PDMS/5% NiTe2 NB FTENGs produced a remarkable output power density of 1.89 mW cm-2 and excellent flexibility. Moreover, these FTENGs with a size of 1 cm2 and 9 cm2 could instantly power 70 and 150 LEDs, respectively, under the periodic vertical force of a human palm tapping. Our results show that NiTe2 NB is an excellent co-triboelectric material with PDMS to achieve high-performance PDMS-based FTENGs. This research was supported by the BK21 Four Program and published in Nano Energy (IF = 17,881), one of the leading journals on nanomaterials and nanodevices for energy harvesting and conversion. Paper title: Enhancing the output power density of polydimethylsiloxane-based flexible triboelectric nanogenerators with ultrathin nickel telluride nanobelts as a co-triboelectric layer
On April 5, a research paper titled "Protein-encoding free-standing RNA hydrogel for sub-compartmentalized translation," written by Professor Soong Ho Um in the school of Chemical Engineering, was published online in the Advanced Materials (IF =30.849) as a cover paper in recognition of its excellence. The research study was conducted in collaboration with Progeneer Inc., a domestic bio-venture company, and it is expected to be used in various biopharmaceutical fields such as cytokine for several medical uses and personalized new drugs because of the outstanding advantages of being able to produce large amounts of functional proteins in a short time. The team has created a new messenger RNA hydrogel structure with physiological and chemical functions by applying the rolling circle transcription and regularly arranging nucleic acid quadruple helical structures based on nucleic acid nanotechnology. RNA plays a pivotal role in regulating and expressing biological activity in vivo, but it is unstable and not easy to produce the desired design. In a situation where these serious and essential limitations are pointed out, this study suggests a wise solution. The team’s research has proved that the biological regulator role of natural RNAs, such as enzyme catalyst action and protein synthesis, is possible outside of cells through bio-inspiration. This technology has exactly reproduced the ‘Spatiotemporal RNA-derived RNA phase transformation’ that occurs in the translation process of the central dogma process, the central principle of life, and thus enabled protein mass-production through gel internal compartmentalization. Since the 1950s, by “cell-free protein expression” technology, protein production could be done outside the cell. With the rapid development of the modern biopharmaceutical market, this is receiving global attention. This study has also contributed to significantly maximizing the efficiency, which is a fatal disadvantage of cell-free protein expression technology. Also, the gel form of RNA is made possible for the first time, and the RNA having various functions secures the high mechanical property. This result suggests the possibility of developing new materials equipped with genetic information. The research’s universal applicability, which solves the fundamental issue of RNA and contributes to the central principle of life, is expected to create various applied technology to pioneer in a new area of research. Progeneer CEOs Chul Kim and Young Ku Lee are directly applying the technology to their personalized anti-cancer vaccine project (ProV-001) and achieving a functional protein synthesis pipeline. Journal Cover, using hydrogel only consisted of RNA to mass produce protein with low cost at short period of time [Research Overview] Examples of mass production of functional proteins using RNA hydrogels technology
Professor Tae Hyun Baek in the Department of Media and Communication has published hisfirst-author study in the 2022 March issue of the Journal of Business Research(IF = 7.550, Q1 in Business/Marketing Category). He collaborated with ProfessorSukki Yoon at Bryant University. He conducted three experimental studies of prosocial advertising on social media to investigate how self-benefit (e.g., “Make your life more meaningful and earn a taxdeduction by giving your support”) and other person-benefit (e.g., “Help others suffering from hunger and make our community a better place by giving yoursupport”) donation appeals paired with pride and gratitude affect donation amounts and donation intentions. He examined incidental and integral emotion induction procedures and used diverse samples of college students and nonstudent adults. Participants induced to feel pride donatedmore significant amounts (Study 1) and donated more frequently (Studies 2 and3) when they viewed Twitter and Instagram ad messages that focused on thebenefits to donors themselves rather than focus on benefits to others in need.However, self-benefit and other-benefit appeals were equally effective wheninduced to show gratitude. This research contributes to theliterature by identifying pride and gratitude as determining the relativeeffectiveness of self-benefit versus other person-benefit appeals. In addition,to the best of our knowledge, this research is the first to investigate howpositive emotions can be matched explicitly with message appeals to influencedonation amounts and intentions to donate. Practically, the findings of this researchhave the potential to impact social media fundraising advertising strategies.For example, nonprofit organizations advertising on Facebook and Twitter mighthighlight their achievements and then provide individualized congratulatoryemails that make recipients feel proud or grateful. For instance, St. JudeChildren’s Research Hospital could advertise its success in increasing survivalrates through innovative research and then send messages that evoke pride. Likewise,the World Wildlife Fund could promote its success in saving endangered speciesfrom extinction and sending thank you messages that evoke gratitude. Relatedly,charity fundraisers might use social media content to trigger feelings of prideand gratitude through corresponding emotion-laden hashtags (e.g., #proud and#grateful) depending on whether the posting contains egoistic or altruisticmessages.
Prof.Jin-Wook Lee`s research team in the SKKU Advanced Nano Technology (SAINT) and Department of Nano Engineering have successfully developed core technologies to significantly improve the stability of perovskite solar cells (PSCs). The research paper was published in the world-renowned scientific journal Nature on March 15, 2022. The PSCs are considered a promising candidate for next-generation photovoltaictechnology due to their high-efficiency and low manufacturing cost. Recently,many researchers in both academia and industry are working on resolving remaining issues for commercialization of the PSCs such as poor long-termoperational stability. For fabrication of high-performance PSCs, reducing crystal defect density in bulk and surface of the perovskite film is essential. A surface passivation strategy by alkylammonium halides has been widely used to enhance the power conversion efficiency of PSCs. However, incorporation of the insulating passivation layer between perovskite and charge transporting layer can cause charge accumulation at the interface and degrade the PSCs' operational stability. The previous studies have only focused on the efficiency improvement by the surface passivation layer, but they did not notice the possible side effects of thesurface passivation layers. Prof.Lee`s team unraveled that the widely used surface passivation layer distorts energy band structure at the heterointerface of the PSCs to impede photo-generated charge collection, and consequently aggravate the stability ofperovskite solar cells. They developed a new surface passivation agent without the side effects to maximize the PSC’s power conversion efficiency and operational stability. As a result, the PSCs fabricated in their study demonstrated the world's best efficiency and stability. Prof.Lee`s research provides advanced understanding of energy band structure at the heterointerfaces based on halide perovskite, expected to resolve the stability issue of the PSCs to accelerate the commercialization of the PSCs. Meanwhile,Prof. Jin-Wook Lee recently published another review paper on ‘A’ site cationin halide perovskites in Science. He was selected as Highly Cited Researchers 2021 (HCR 2021) by Clarivate Analytics in the field of cross-field. ※ Related research papers and website 1) Stability-limiting heterointerfaces of perovskite photovoltaics, Nature, 2022, doi.org/10.1038/s41586-022-04604-5. ( corresponding author: Prof. Jin-Wook Lee, co-author: Keonwoo Park 2) Rethinking the A cation in halide perovskites, Science, 2022, 375,835. (First author: Prof. Jin-Wook Lee) 3) Prof. Jin-Wook Lee`s Lab website: https://jwlee870217.wixsite.com/mysite Figure 1. charge displacement onperovskite film surface by surface defect healing ions Figure 2. Operational stability ofperovskite solar cells with different surface passivation strategies