| 1. |
- Xu, Weidong, et al.
(författare)
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Iodomethane-Mediated Organometal Halide Perovskite with Record Photoluminescence Lifetime
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 8:35, s. 23181-23189
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Tidskriftsartikel (refereegranskat)abstract
- Organometallic lead halide perovskites are excellent light harvesters for high-efficiency photovoltaic devices. However, as the key component in these devices, a perovskite thin film with good morphology and minimal trap states is still difficult to obtain. Herein we show that by incorporating a low boiling point alkyl halide such as iodomethane (CH3I) into the precursor solution, a perovskite (CH3NH3PbI3-xClx) film with improved grain size and orientation can be easily achieved. More importantly, these films exhibit a significantly reduced amount of trap states. Record photoluminescence lifetimes of more than 4 mu s are achieved; these lifetimes are significantly longer than that of pristine CH3NH3PbI3-xClx films. Planar heterojunction solar cells incorporating these CH3I-mediated perovskites have demonstrated a dramatically increased power conversion efficiency compared to the ones using pristine CH3NH3PbI3-xClx. Photoluminescence, transient absorption, and microwave detected photoconductivity measurements all provide consistent evidence that CH3I addition increases the number of excitons generated and their diffusion length, both of which assist efficient carrier transport in the photovoltaic device. The simple incorporation of alkyl halide to enhance perovskite surface passivation introduces an important direction for future progress on high efficiency perovskite optoelectronic devices.
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| 2. |
- Xu, Yalong, et al.
(författare)
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Simultaneously Improved Efficiency and Stability in All-Polymer Solar Cells by a P-i-N Architecture
- 2019
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Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 4:9, s. 2277-2286
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Tidskriftsartikel (refereegranskat)abstract
- All-polymer organic solar cells offer exceptional stability. Unfortunately, the use of bulk heterojunction (BHJ) structure has the intrinsic challenge to control the side-chain entanglement and backbone orientation to achieve sophisticated phase separation in all-polymer blends. Here, we revealed that the P-i-N structure can outperform the BHJ ones with a nearly 50% efficiency improvement, reaching a power conversion efficiency approaching 10%. This P-i-N structure can also provide an enhanced internal electric field and remarkably stable morphology Sequential deposition under harsh thermal stress. We have further demonstrated generality of the P-i-N structure in several other all-polymer systems. Considering the adjustable polymer molecular weight and solubility, the P-i-N device structure can be more beneficial for all-polymer systems. With the design of more crystalline polymers, the antiquated P-i-N structure can further show its strength in all-polymer systems by simplified morphology control and improved carrier extraction, becoming a more favorite device structure than the dominant BHJ structure.
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| 3. |
- Wang, Jian, et al.
(författare)
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A High-Level Thermal Model-Based Task Mapping for CMPs in Dark-Silicon Era
- 2016
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Ingår i: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383 .- 1557-9646. ; 63:9, s. 3406-3412
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Tidskriftsartikel (refereegranskat)abstract
- The chip multiprocessor (CMP) thermal issue impacting the system reliability and cooling cost has become a limiting factor for chip scaling and attracted growing attentions in the dark-silicon era. We propose a thermal-aware thread-to-core mapping method for CMPs under the dark-silicon constraint. We first propose a high-level spatial-temporal information-based thermal model to capture the relationship between the mapping result and the system thermal distribution. Then, we develop a thermal-aware mapping algorithm, which can automatically assign threads to proper cores based on the proposed model. Finally, we evaluate our method through simulations. Compared with three other mapping methods, namely, random, network-on-chip (NoC)-sprinting and round-robin, our thermal-priority design decreases the peak temperature by up to 4.31 K while showing good communication performance (34.7% of improvement against random and 50.3% against NoC sprinting, and only 6.3% of degradation against round robin); and our latency-priority design achieves the best communication performance with an improvement up to 62.6% and a satisfactory thermal profile.
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