Organic–inorganic hybrid perovskites play an important role in improving the efficiency of solid-state dye-sensitized solar cells. In this paper, we systematically explore the efficiency-enhancing mechanism of ABX_3...Organic–inorganic hybrid perovskites play an important role in improving the efficiency of solid-state dye-sensitized solar cells. In this paper, we systematically explore the efficiency-enhancing mechanism of ABX_3（A = CH_3NH_3; B = Sn,Pb; X = Cl, Br, I） and provide the best absorber among ABX_3 when the organic framework A is CH_3NH_3 by first-principles calculations. The results reveal that the valence band maximum（VBM） of the ABX_3 is mainly composed of anion X p states and that conduction band minimum（CBM） of the ABX_3 is primarily composed of cation B p states. The bandgap of the ABX_3 decreases and the absorptive capacities of different wavelengths of light expand when reducing the size of the organic framework A, changing the B atom from Pb to Sn, and changing the X atom from Cl to Br to I. Finally, based on our calculations, it is discovered that CH_3NH_3 Sn I_3has the best optical properties and its light-adsorption range is the widest among all the ABX_3 compounds when A is CH_3NH_3. All these results indicate that the electronegativity difference between X and B plays a fundamental role in changing the energy gap and optical properties among ABX_3 compounds when A remains the same and that CH_3NH_3 Sn I_3 is a promising perovskite absorber in the high efficiency solar batteries among all the CH_3NH_3BX_3 compounds.展开更多
A infrared light trapping structure combining front subwavelength gratings and rear ZnO：Al nanoparticles for a PtSi Schottky-barrier detector over a 3-5 μm waveband is theoretically investigated. By selecting the pr...A infrared light trapping structure combining front subwavelength gratings and rear ZnO：Al nanoparticles for a PtSi Schottky-barrier detector over a 3-5 μm waveband is theoretically investigated. By selecting the proper plasmonic material and optimizing the parameters for the proposed structure, the absorption of the PtSi layer is dramatically improved. The theoretical results show that this improvement eventually translates into an equivalent external quantum efficiency （EQE） enhancement of 2.46 times at 3-3.6 μm and 2.38 times at 3.6-5 μm compared to conventional structures. This improvement in the EQE mainly lies in the increase of light path lengths witifin the PtSi layer by the subwavelength grating diffraction and nanoparticle-scattering effects.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61366007,11164032,and 61066005)the Program for New Century Excellent Talents in University of Ministry of Education of China(Grant No.NCET-12-1080)+1 种基金the Basic Applied Research Foundation of Yunnan Province,China(Grant Nos.2011CI003 and 2013FB007)the Excellent Young Talents in Yunnan University,China
文摘Organic–inorganic hybrid perovskites play an important role in improving the efficiency of solid-state dye-sensitized solar cells. In this paper, we systematically explore the efficiency-enhancing mechanism of ABX_3（A = CH_3NH_3; B = Sn,Pb; X = Cl, Br, I） and provide the best absorber among ABX_3 when the organic framework A is CH_3NH_3 by first-principles calculations. The results reveal that the valence band maximum（VBM） of the ABX_3 is mainly composed of anion X p states and that conduction band minimum（CBM） of the ABX_3 is primarily composed of cation B p states. The bandgap of the ABX_3 decreases and the absorptive capacities of different wavelengths of light expand when reducing the size of the organic framework A, changing the B atom from Pb to Sn, and changing the X atom from Cl to Br to I. Finally, based on our calculations, it is discovered that CH_3NH_3 Sn I_3has the best optical properties and its light-adsorption range is the widest among all the ABX_3 compounds when A is CH_3NH_3. All these results indicate that the electronegativity difference between X and B plays a fundamental role in changing the energy gap and optical properties among ABX_3 compounds when A remains the same and that CH_3NH_3 Sn I_3 is a promising perovskite absorber in the high efficiency solar batteries among all the CH_3NH_3BX_3 compounds.
基金supported by the National Natural Science Foundation of China(No.61471044)the Advanced Research Foundation of China(No.9140A02010114BQ01)
文摘A infrared light trapping structure combining front subwavelength gratings and rear ZnO：Al nanoparticles for a PtSi Schottky-barrier detector over a 3-5 μm waveband is theoretically investigated. By selecting the proper plasmonic material and optimizing the parameters for the proposed structure, the absorption of the PtSi layer is dramatically improved. The theoretical results show that this improvement eventually translates into an equivalent external quantum efficiency （EQE） enhancement of 2.46 times at 3-3.6 μm and 2.38 times at 3.6-5 μm compared to conventional structures. This improvement in the EQE mainly lies in the increase of light path lengths witifin the PtSi layer by the subwavelength grating diffraction and nanoparticle-scattering effects.
