http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Efficient Heterotransfer between Visible Quantum Dots
Yin, Wenping,Kim, Namhun,Jeong, Jaehak,Kim, Kil Suk,Chae, Heeyeop,Ahn, Tae Kyu American Chemical Society 2017 The Journal of Physical Chemistry Part C Vol.121 No.9
<P>We fabricated green-red (GR) and blue-red (BR) bilayer stacked quantum dots (QDs) using electrospray deposition. Along with steady state and time-resolved photoluminescence (PL), subnanosecond donor PL decay and corresponding acceptor PL rise signals were observed, which are ascribed to the energy transfer between different visible QDs (heterotransfer). The heterotransfer rates were estimated as (0.57 +/- 0.01 ns)(-1) and (0.65 0.02 ns)(-1) for GR and BR systems, respectively, which agree well with theoretical calculations. Owing to their geometrical proximity, mixed QD layers with GR and BR showed qualitatively higher heterotransfer efficiencies of 64% and 81%, compared to stacked QD layers, which have efficiencies of 23% and 64%, respectively.</P>
Zhao, Pengjun,Han, Manhyung,Yin, Wenping,Zhao, Xing,Kim, Seul Gi,Yan, Yaping,Kim, Minwoo,Song, Young Jae,Park, Nam Gyu,Jung, Hyun Suk American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.12
<P>Currently, the most efficient perovskite solar cells (PSCs) mainly use planar and mesoporous titanium dioxide (TiO<SUB>2</SUB>) as an electron-transport layer (ETL). However, because of its intrinsic photocatalytic properties, TiO<SUB>2</SUB> can decompose perovskite absorber and lead to poor stability under solar illumination (ultraviolet light). Herein, a simplified architectural ETL-free PSC with enhanced efficiency and outstanding photostability is produced by the facile deposition of a bathocuproine (BCP) interlayer. Power conversion efficiency of the ETL-free PSC improves from 15.56 to 19.07% after inserting the BCP layer, which is the highest efficiency reported for PSCs involving an ETL-free architecture, versus 19.03% for the n-i-p full device using TiO<SUB>2</SUB> as an ETL. The BCP interlayer has been demonstrated to have several positive effects on the photovoltaic performances of devices, such as “modulation doping” of the perovskite layer, modification of FTO surface work function, and enhancing the charge-transfer efficiency between FTO and perovskite. Moreover, the BCP-based ETL-free devices exhibit outstanding photostability: the unencapsulated BCP-based ETL-free PSCs retain over 90% of their initial efficiencies after 1000 h of storage in air and maintain 92.2% after 450 h of exposure to full solar irradiation (without a UV filter), compared to only 14.1% in the n-i-p full cells under the same condition.</P> [FIG OMISSION]</BR>
High Temperature Oxidation Resistance of NiCoCrAl High Entropy Alloy Coating on the TiAl Alloy
Yuanyuan Sun,Qiang Miao,Wenping Liang,Kai Zang,Yuting Wu,Haiyang Yu,Mengjuan Yin,Xiguang Gao,Yindong Song 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1
The high entropy alloy coating is considered as one of the most promising methods to improve the high-temperature oxidationresistance of titanium aluminum alloys due to its fine mechanical property and thermal stability. However, the high entropyalloy coating prepared so far has poor coating quality, and low coating forming efficiency and there are certain requirementsfor the substrate alloys. To this end, a NiCoCrAl high entropy alloy coating was developed using the double glow plasmaalloying technique on the TiAl alloy. The morphology, phase structure, and high temperature oxidation resistance of thecoating were comprehensively studied. The results indicate that a uniform and dense coating with a single solid solution offace-centered cube phase formed on the alloy surface. Furthermore, isothermal oxidation test was performed, and the oxidationfailure process of the TiAl substrate and the NiCoCrAl-coated sample with different oxidation times was analyzed. It isfound that the coating efficiently prevented the TiAl alloy from degeneration for up to 100 h at 900 °C.
Jeon, Seolhee,Thakur, Ujwal Kumar,Lee, Daehee,Wenping, Yin,Kim, Dasom,Lee, Sunjong,Ahn, Tae Kyu,Park, Hui Joon,Kim, Bong-Gi Elsevier 2016 ORGANIC ELECTRONICS Vol.37 No.-
<P><B>Abstract</B></P> <P>Novel conjugated materials, DPIO and DPIE, having same molecular configuration of both an electron donating <I>N</I>-phenylindole and an electron accepting diketopyrrolopyrrole derivative, exhibited different aggregation behavior because of the applied side chains. When DPIO and DPIE were applied to as hole transporting materials in perovskite solar cell, DPIO showed better device performance than ones with DPIE, mostly due to the aggregation-assisted enhanced electrical property. DPIO effectively extracted hole from the perovskite layer, providing over 10% PCE of cell efficiency without any chemical doping. Incident-photon-to-electron conversion efficiency (IPCE) measurement confirmed that DPIO’s strong absorption in the longer wavelength region partly contributed to the light harvesting of the solar cell device. In addition, time-resolved photoluminescence (TRPL) and transient photovoltage (TPV) studies proved that the DPIO-based device, compared to the conventional Spiro-MeOTAD-based device, has better charge extraction ability and reduced charge recombination.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Side chains provide different aggregation behaviors in organic semiconductors. </LI> <LI> Electrical property of organic semiconductors is affected by molecular aggregation. </LI> <LI> Molecular aggregation strongly affects the device performance of perovskite solar cells. </LI> <LI> Organic semiconductors showing high aggregation behavior would be advantageous for dopant-free hole transporting material. </LI> <LI> Organic dipolar semiconductors could reduce the degree of charge recombination. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Shin, Seong Sik,Suk, Jae Ho,Kang, Bong Joo,Yin, Wenping,Lee, Seon Joo,Noh, Jun Hong,Ahn, Tae Kyu,Rotermund, Fabian,Cho, In Sun,Seok, Sang Il The Royal Society of Chemistry 2019 ENERGY AND ENVIRONMENTAL SCIENCE Vol.12 No.3
<P>Next-generation solar cells, such as dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs), are fabricated in a configuration where light absorbers are located between the electron transporting layer (ETL) and the hole transporting layer (HTM). Although the most efficient DSSCs and PSCs have been fabricated using TiO2 as the ETL, TiO2 exhibits inherently low electron mobility with difficulty controlling the energy levels (<I>i.e.</I>, conduction and valence bands) as it possesses a single phase of two components. Here, we report the synthesis of Sr-substituted BaSnO3 (BSSO) by a low-temperature solution process as a new alternative to TiO2 for both PSCs and DSSCs. The energy-level tailoring by Sr incorporation into BaSnO3 minimizes the open-circuit voltage (<I>V</I>OC) loss at the interfaces of ETL/perovskite and ETL/electrolyte in the PSCs and DSSCs, thereby leading to an improved <I>V</I>OC from 0.65 to 0.72 V in DSSC and 1.07 to 1.13 V in PSCs. Additionally, the BSSO ETL-based PSC shows improved photostability compared to the TiO2 analog. Our results show that energy-level tuned BSSO can be applied as a universal ETL for improving efficiency in both PSCs and DSSCs.</P>