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Author

Yujia Guo

Bio: Yujia Guo is an academic researcher from Xidian University. The author has contributed to research in topics: Perovskite (structure) & Dopant. The author has an hindex of 2, co-authored 4 publications receiving 8 citations.

Papers
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Journal ArticleDOI
Yujia Guo1, Jie Su1, Lu Wang1, Zhenhua Lin1, Yue Hao1, Jingjing Chang1 
TL;DR: In this paper, the structural, electronic, and optical properties of Zn and Mn codoped CsPbBr3 have been investigated based on first-principle calculations and experimental verifications.
Abstract: Reducing the toxic Pb component in perovskites is an important step to realize environment-friendly perovskite optoelectronic devices Herein, the structural, electronic, and optical properties of Zn and Mn codoped CsPbBr3 have been investigated based on first-principle calculations and experimental verifications Although the Zn dopant could reduce the optical band gap and exciton binding energy and enhance the optical absorption and defect tolerance for CsPbBr3, the maximum reduction of the toxic Pb component was just about 125% in the experiment because the Zn dopant enlarges the formation energy of CsPb1-xZnxBr3 For the stable CsPb1-x-yMnxZnyBr3 perovskite, the largest y and corresponding (x + y) could reach up to 25% and 83% respectively, since the Mn dopant could reduce the structural disorder Especially when (x + y) < 50%, CsPb1-x-yMnxZnyBr3 exhibits a comparable carrier lifetime and exciton binding energy with a lower band gap to those of the CsPbBr3, since the Zn dopant supplies a charge to CsPbBr3 to counteract the variation of Pb-Br bonds induced by the Mn dopant Meanwhile, the d orbitals of the dopant increase the optical absorption These suggest that a 50% reduction of toxic Pb could be realized for stable CsPb1-x-yMnxZnyBr3 with negligibly deteriorated optoelectronic properties This work provides an alternative approach to achieve a Pb-less perovskite with a high performance

26 citations

Journal ArticleDOI
TL;DR: This work uses two-photon laser lithography to fabricate bioinspired bigrating nanostructures, whose optical properties may be controlled by variation of the height and period of the grating features, and demonstrates that variation of feature period and/or height plays a central role in controlling both hue and purity.
Abstract: Multilayer grating structures, such as those found on the wings of the butterfly Cynandra opis, are able to interact with light to generate structural coloration. When illuminated and viewed at defined angles, such structural color is characterized by exceptional purity and brightness. To provide further insight into the mechanism of structural coloration, two‐photon laser lithography is used to fabricate bioinspired bigrating nanostructures, whose optical properties may be controlled by variation of the height and period of the grating features. Through the use of both spectral measurements and finite‐element method simulations, herein specific feature dimensions are identified that due to the combined effects of multilayer interference and diffraction generate excellent spectral characteristics and high color purity over the entire visible range. Additionally, it is demonstrated that variation of feature period and/or height plays a central role in controlling both hue and purity. Importantly, such tuneable bigrating structures are of significant utility in color filtering applications.

20 citations

Journal ArticleDOI
Peng Zhao1, Jie Su1, Yujia Guo1, Lu Wang1, Zhenhua Lin1, Yue Hao1, Xiaoping Ouyang1, Jingjing Chang1 
TL;DR: In this paper, a new discovery is shed on the vacancy-ordered double perovskite Cs2TiII6, a potential nontoxic and stable material for high-performance solar cell and α-particle detection.
Abstract: The lead contamination and long-term stability are the two important problems limiting the commercialization of organic-inorganic lead halide perovskites. In this study, through an innovative multi-scale simulation strategy based on the first-principle calculations coupling with drift-diffusion model and Monte Carlo method, a new discovery is shed on the vacancy-ordered double perovskite Cs2TiI6, a potential nontoxic and stable perovskite material for high-performance solar cell and α-particle detection. The excellent photon absorption character and ultrahigh carrier mobility (μn = 2.26×104 cm2/Vs, μp = 7.38×103 cm2/Vs) of Cs2TiI6 induce ultrahigh power conversion efficiency (PCE) for both single-junction solar cell (22.70%) and monolithic all-perovskite tandem solar cell (26.87%). Moreover, the outstanding device performance can be remained even in high energy charge particle detection (α-particle) with excellent charge collection efficiency (CCE = 99.2%) and mobility-lifetime product (μτh = 1×10−3 cm2/V). Furthermore, to our surprise, the solar cell and α-particle detector based on Cs2TiI6 material are able to withstand ultrahigh fluence proton beam up to 1013 and 1015 p/cm2 respectively, which strongly suggests that semiconductor devices based on Cs2TiI6 material are able to apply in the astrospace. The multi-scale simulation connecting from material to device reveals that Cs2TiI6 perovskite has the great potential for photovoltaic cells, α-particle detection and even their space application.

13 citations

Journal ArticleDOI
TL;DR: In this paper, a new vacancy-ordered double perovskite Cs2CrI6 was found to realize high performance space solar cells and α-particle detectors through an innovative multi-scale simulation strategy based on the first-principle calculations coupling with drift-diffusion model and Monte Carlo method.

12 citations

Journal ArticleDOI
Lu Wang1, Jie Su1, Yujia Guo1, Zhenhua Lin1, Yue Hao1, Jingjing Chang1 
TL;DR: In this article, surface Cu doping can bend down the band levels and decline the VBM of the CsPb1-xGexBr3 surface below the H2O/O2 potential, then prevent the Ge2+ from being oxidized into Ge4+ by water.
Abstract: Ge doping has been regarded as an effective way to explore the low-toxicity inorganic halide perovskite. However, Ge2+ ions are easy to oxidize because the Ge dopant raises the valence band maximum (VBM) over the water oxidization (H2O/O2) potential. Here we find that surface Cu doping can bend down the band levels and decline the VBM of the CsPb1-xGexBr3 surface below the H2O/O2 potential, then prevent the Ge2+ from being oxidized into Ge4+ by water because the Cu dopant reduces the perovskite surface electron accumulation. Note that the Cu dopant prefers to locate at the perovskite surface rather than the interior, and it reduces the surface energy and enhances the stability. Consequently, the largest Pb reduction increases to 97.3% for the Cu-doped CsPb1-xGexBr3 surface. Moreover, the exciton binding energy and optical absorption of CsPb1-xGexBr3 could be further improved by the surface Cu dopant. This work provides guidance for finding low-toxicity stable inorganic perovskites.

12 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a theoretical study on lead-free, environmental-friendly CsGeI3-based solar cell (SC) is demonstrated, and the simulation results demonstrated 10.8% optimized PCE, Jsc of 22.08 mAcm−2, Voc of 0.667 V, and FF of 73.49%.

31 citations

Journal ArticleDOI
TL;DR: In this article , a theoretical study on lead-free, environmental-friendly CsGeI3-based solar cell (SC) is demonstrated, and the simulation results demonstrated 10.8% optimized PCE, Jsc of 22.08 mAcm−2, Voc of 0.667 V, and FF of 73.49%.

31 citations

Journal ArticleDOI
Yujia Guo1, Jie Su1, Lu Wang1, Zhenhua Lin1, Yue Hao1, Jingjing Chang1 
TL;DR: In this paper, the structural, electronic, and optical properties of Zn and Mn codoped CsPbBr3 have been investigated based on first-principle calculations and experimental verifications.
Abstract: Reducing the toxic Pb component in perovskites is an important step to realize environment-friendly perovskite optoelectronic devices Herein, the structural, electronic, and optical properties of Zn and Mn codoped CsPbBr3 have been investigated based on first-principle calculations and experimental verifications Although the Zn dopant could reduce the optical band gap and exciton binding energy and enhance the optical absorption and defect tolerance for CsPbBr3, the maximum reduction of the toxic Pb component was just about 125% in the experiment because the Zn dopant enlarges the formation energy of CsPb1-xZnxBr3 For the stable CsPb1-x-yMnxZnyBr3 perovskite, the largest y and corresponding (x + y) could reach up to 25% and 83% respectively, since the Mn dopant could reduce the structural disorder Especially when (x + y) < 50%, CsPb1-x-yMnxZnyBr3 exhibits a comparable carrier lifetime and exciton binding energy with a lower band gap to those of the CsPbBr3, since the Zn dopant supplies a charge to CsPbBr3 to counteract the variation of Pb-Br bonds induced by the Mn dopant Meanwhile, the d orbitals of the dopant increase the optical absorption These suggest that a 50% reduction of toxic Pb could be realized for stable CsPb1-x-yMnxZnyBr3 with negligibly deteriorated optoelectronic properties This work provides an alternative approach to achieve a Pb-less perovskite with a high performance

26 citations

Journal ArticleDOI
TL;DR: In this paper , a simple method is presented to reduce Eloss and improve the open-circuit voltage (Voc) of the CsPbIBr2 PSCs through effective surface reconstruction with formamidinium iodide.

24 citations

Journal ArticleDOI
TL;DR: In this article, a polymer additive of polyethylene glycol (PEG) was employed to passivate the localized defects in CsPbI2Br films through the Lewis acid-base interaction.
Abstract: Solution-processable all-inorganic lead halide perovskites are under intensive attention due to their potential applications in low-cost high-performance optoelectronic devices such as photodetectors. However, solution processing usually generates structural and chemical defects which are detrimental to the photodetection performance of photodetectors. Here, a polymer additive of polyethylene glycol (PEG) was employed to passivate the localized defects in CsPbI2Br films through the Lewis acid-base interaction. The interfacial defects were passivated efficiently by introducing a trace amount of a PEG additive with a concentration of 0.4 mg mL-1 into the CsPbI2Br precursor solution, as suggested by the significantly reduced trap density of state, which was revealed using thermal admittance spectroscopy. Fourier transform infrared spectrum characterization showed that rather than Cs+ or I-, a Lewis acid-base interaction was established between Pb2+ and PEG to passivate the defects in the CsPbI2Br perovskite, which leads to large suppression of noise current. Both specific detectivity and linear dynamic range improved from 4.1 × 109 Jones and 73 dB to 2.2 × 1011 Jones and 116 dB, respectively. Our work demonstrates the feasibility of employing an environmentally stable polymeric additive PEG to passivate defects for high photodetection performance in all-inorganic perovskite photodetectors.

20 citations