(Invited) Time-Resolved EPR Study on Charge Dynamics of Electron-Hole Pairs in Lead Iodide Perovskite Thin Film

2017 ◽  
Keyword(s):  
Thin Film ◽  
Lead Iodide ◽  
Electron Hole ◽  
Time Resolved ◽  
Charge Dynamics

scholarly journals Effects of 5-Ammonium Valeric Acid Iodide as Additive on Methyl Ammonium Lead Iodide Perovskite Solar Cells

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2512
Author(s):  
Daming Zheng ◽  
Changheng Tong ◽  
Tao Zhu ◽  
Yaoguang Rong ◽  
Thierry Pauporté
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Single Crystal Silicon ◽  
Mesoporous Structure ◽  
Valeric Acid ◽  
Electrical Impedance Spectroscopy ◽  
Lead Iodide ◽  
Crystal Silicon ◽  
Time Resolved ◽  
Hole Transporting

During the past decade, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has risen rapidly, and it now approaches the record for single crystal silicon solar cells. However, these devices still suffer from a problem of stability. To improve PSC stability, two approaches have been notably developed: the use of additives and/or post-treatments that can strengthen perovskite structures and the use of a nontypical architecture where three mesoporous layers, including a porous carbon backcontact without hole transporting layer, are employed. This paper focuses on 5-ammonium valeric acid iodide (5-AVAI or AVA) as an additive in methylammonium lead iodide (MAPI). By combining scanning electron microscopy (SEM), X-ray diffraction (XRD), time-resolved photoluminescence (TRPL), current–voltage measurements, ideality factor determination, and in-depth electrical impedance spectroscopy (EIS) investigations on various layers stacks structures, we discriminated the effects of a mesoscopic scaffold and an AVA additive. The AVA additive was found to decrease the bulk defects in perovskite (PVK) and boost the PVK resistance to moisture. The triple mesoporous structure was detrimental for the defects, but it improved the stability against humidity. On standard architecture, the PCE is 16.9% with the AVA additive instead of 18.1% for the control. A high stability of TiO2/ZrO2/carbon/perovskite cells was found due to both AVA and the protection by the all-inorganic scaffold. These cells achieved a PCE of 14.4% in the present work.

Observing Charge Dynamics in Surface Reactions by Time-Resolved Stark Effects

2013 ◽  
Vol 117 (18) ◽  
pp. 9171-9177 ◽  
Author(s):  
Michael Meister ◽  
Björn Baumeier ◽  
Neil Pschirer ◽  
Rüdiger Sens ◽  
Ingmar Bruder ◽  
...  
Keyword(s):  
Surface Reactions ◽  
Time Resolved ◽  
Charge Dynamics ◽  
Stark Effects

A Comparison of Radiation Versus Convection Calibration of Thin-Film Heat Flux Gauges

1999 ◽  
Author(s):  
D. E. Smith ◽  
J. V. Bubb ◽  
O. Popp ◽  
T. E. Diller ◽  
Stephen J. Hevey
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Surface Temperature ◽  
Temperature Response ◽  
Turbine Rotor ◽  
Separate Experiment ◽  
Measured Temperature ◽  
Conduction Model ◽  
Time Resolved ◽  
Turbine Rotor Blade

Abstract A transient, in-situ method was examined for calibrating thin-film heat flux gauges using experimental data generated from both convection and radiation tests. Also, a comparison is made between this transient method and the standard radiation substitution calibration technique. Six Vatell Corporation HFM-7 type heat flux gauges were mounted on the surface of a 2-D, first-stage turbine rotor blade. These gauges were subjected to radiation from a heat lamp and in a separate experiment to a convective heat flux generated by flow in a transonic cascade wind tunnel. A second set of convective tests were performed using jets of cooled air impinging on the surface of the gauges. Direct measurements were simultaneously taken of both the time-resolved heat flux and surface temperature on the blade. The heat flux input was used to predict a surface temperature response using a one-dimensional, semi-infinite conduction model into a substrate with known thermal properties. The sensitivities of the gauges were determined by correlating the semi-infinite predicted temperature response to the measured temperature response. A finite-difference code was used to model the penetration of the heat flux into the substrate in order to estimate the time for which the semi-infinite assumption was valid. The results from these tests showed that the gauges accurately record both the convection and radiation modes of heat transfer. The radiation and convection tests yielded gauge sensitivities which agreed to within ±11%.

Characteristics of Perovskite Solar Cells with Methylammonium Iodide-Added Anti-Solvent

2021 ◽  
Vol 21 (8) ◽  
pp. 4367-4371
Author(s):  
Sung Hwan Joo ◽  
Il Tae Kim ◽  
Hyung Wook Choi
Keyword(s):  
Solar Cell ◽  
Perovskite Solar Cells ◽  
Lead Iodide ◽  
Step Method ◽  
Electron Hole ◽  
Perovskite Layer ◽  
Solar Cell Efficiency ◽  
Cell Efficiency ◽  
One Step ◽  
Hole Recombination

The perovskite film—manufactured via a one-step method—was superficially improved through an anti-solvent process to increase solar cell efficiency. Although perovskite synthesis proceeds rapidly, a significant amount of lead iodide residue remains. Well-placed lead iodide in perovskite grains prevents electron–hole recombination; however, when irregularly placed, it interferes with the movement of electron and holes. In this study, we focused on improving the crystallinity of the perovskite layer, as well as reducing lead iodide residues by adding a methylammonium halide material to the anti-solvent. Methylammonium iodide in chlorobenzene used as an anti-solvent reduces lead iodide residues and improves the crystallinity of formamidinium lead iodide perovskite. The improved crystallinity of the perovskite layer increased the absorbance and, with reduced lead iodide residues, increased the efficiency of the perovskite solar cell by 1.914%.

Large scale alignment of a lamellar block copolymer thin film via electric fields: a time-resolved SFM study

Soft Matter ◽  
2006 ◽  
Vol 2 (12) ◽  
pp. 1089-1094 ◽  
Author(s):  
Violetta Olszowka ◽  
Markus Hund ◽  
Volker Kuntermann ◽  
Sabine Scherdel ◽  
Larisa Tsarkova ◽  
...  
Keyword(s):  
Thin Film ◽  
Block Copolymer ◽  
Electric Fields ◽  
Large Scale ◽  
Time Resolved ◽  
Large Scale Alignment

Spatially resolved investigation of the defect states in methylammonium lead iodide perovskite bicrystals

2019 ◽  
Vol 7 (42) ◽  
pp. 13156-13160 ◽  
Author(s):  
Svetlana Sirotinskaya ◽  
Christian Fettkenhauer ◽  
Daichi Okada ◽  
Yohei Yamamoto ◽  
Doru C. Lupascu ◽  
...  
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
System Approach ◽  
Defect States ◽  
Lead Iodide ◽  
Modal System ◽  
Trap Formation ◽  
Spatially Resolved ◽  
Methylammonium Lead Iodide

Introducing a modal system approach for the analytical perovskite thin-film trap physics evaluation. Our study confirms existing models for trap formation in MAPI, substantiating different defect states in the grain boundary and bulk regions.

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