A study of trap and recombination centers in MAPbI3 perovskites

2016 ◽  
Vol 18 (48) ◽  
pp. 32862-32867 ◽  
Author(s):  
G. Gordillo ◽  
C. A. Otálora ◽  
A. A. Ramirez
Keyword(s):  
Thin Films ◽  
Measurement System ◽  
Influence Of Temperature ◽  
Transient Photoconductivity ◽  
Recombination Processes ◽  
Recombination Centers ◽  
Relaxation Curves ◽  
Theoretical Simulations ◽  
Photoconductivity Response

Trapping and recombination processes in thin films of CH3NH3PbI3 (MAPbI3) were studied by means of transient photoconductivity measurements and theoretical simulations of the relaxation curves resulting from the photocurrent measurements; in particular, the influence of temperature, as well as of the sample intensity of temperature illumination and pressure inside the measurement system on the photoconductivity response were studied.

scholarly journals Influence of Heterointerfaces on the Kinetics of Oxygen Surface Exchange on Epitaxial La1.85Sr0.15CuO4 Thin Films

2021 ◽  
Vol 11 (9) ◽  
pp. 3778
Author(s):  
Gene Yang ◽  
So-Yeun Kim ◽  
Changhee Sohn ◽  
Jong K. Keum ◽  
Dongkyu Lee
Keyword(s):  
Thin Films ◽  
Oxygen Vacancies ◽  
Elevated Temperatures ◽  
Surface Exchange ◽  
Electrical Conductivity Relaxation ◽  
Exchange Kinetics ◽  
Relaxation Curves ◽  
Kinetics Of ◽  
Oxygen Surface Exchange ◽  
Oxygen Surface

Considerable attention has been directed to understanding the influence of heterointerfaces between Ruddlesden–Popper (RP) phases and ABO3 perovskites on the kinetics of oxygen electrocatalysis at elevated temperatures. Here, we report the effect of heterointerfaces on the oxygen surface exchange kinetics by employing heteroepitaxial oxide thin films formed by decorating LaNiO3 (LNO) on La1.85Sr0.15CuO4 (LSCO) thin films. Regardless of LNO decoration, tensile in-plane strain on LSCO films does not change. The oxygen surface exchange coefficients (kchem) of LSCO films extracted from electrical conductivity relaxation curves significantly increase with partial decorations of LNO, whereas full LNO coverage leads to the reduction in the kchem of LSCO films. The activation energy for oxygen exchange in LSCO films significantly decreases with partial LNO decorations in contrast with the full coverage of LNO. Optical spectroscopy reveals the increased oxygen vacancies in the partially covered LSCO films relative to the undecorated LSCO film. We attribute the enhanced oxygen surface exchange kinetics of LSCO to the increased oxygen vacancies by creating the heterointerface between LSCO and LNO.

MeV Ion-Beam Bombardment Effects on The Thermoelectric Figures of Merit of Zn4Sb3 and ZrNiSn-Based half-heusler compounds

2007 ◽  
Vol 1020 ◽  
Author(s):  
S. Budak ◽  
S. Guner ◽  
C. Muntele ◽  
C. C. Smith ◽  
B. Zheng ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Measurement System ◽  
Ion Beam ◽  
Electrical Energy ◽  
Figures Of Merit ◽  
Material Systems ◽  
The Cross ◽  
Conductivity Of Thin Films

AbstractSemiconducting â-Zn4Sb3and ZrNiSn-based half-heusler compound thin films were prepared by co-evaporation for the application of thermoelectric (TE) materials. High-purity solid zinc and antimony were evaporated by electron beam to grow the â-Zn4Sb3thin film while high-purity zirconium powder and nickel tin powders were evaporated by electron beam to grow the ZrNiSn-based half-heusler compound thin film. Rutherford backscattering spectrometry (RBS) was used to analyze the composition of the thin films. The grown thin films were subjected to 5 MeV Si ions bombardments for generation of nanostructures in the films. We measured the thermal conductivity, Seebeck coefficient, and electrical conductivity of these two systems before and after 5 MeV Si ions beam bombardments. The two material systems have been identified as promising TE materials for the application of thermal-to-electrical energy conversion, but the efficiency still limits their applications. The electronic energy deposited due to ionization in the track of MeV ion beam can cause localized crystallization. The nanostructures produced by MeV ion beam can cause significant change in both the electrical and the thermal conductivity of thin films, thereby improving the efficiency. We used the 3ù-method measurement system to measure the cross-plane thermal conductivity ,the Van der Pauw measurement system to measure the cross-plane electrical conductivity, and the Seebeck-coefficient measurement system to measure the cross-plane Seebeck coefficient. The thermoelectric figures of merit of the two material systems were then derived by calculations using the measurement results. The MeV ion-beam bombardment was found to decrease the thermal conductivity of thin films and increase the efficiency of thermal-to-electrical energy conversion.

Recombination processes in doubly capped antimonide-based quaternary thin films

1999 ◽  
Vol 86 (3) ◽  
pp. 1527-1534 ◽  
Author(s):  
Sudesh Saroop ◽  
Jose M. Borrego ◽  
Ronald J. Gutmann ◽  
Greg W. Charache ◽  
Christine A. Wang
Keyword(s):  
Thin Films ◽  
Recombination Processes

scholarly journals Влияние связующего и красителей на механизм туннельной люминесепнции микрокристаллов AgBr(I)

2020 ◽  
Vol 128 (8) ◽  
pp. 1100
Author(s):  
А.В. Тюрин ◽  
С.А. Жуков ◽  
А.Ю. Ахмеров
Keyword(s):  
Silver Ions ◽  
Point Of View ◽  
Exciting Light ◽  
Absorption Region ◽  
Recombination Processes ◽  
Tunneling Recombination ◽  
Recombination Centers ◽  
Kinetics Of ◽  
Stationary Level ◽  
Ir Light

It was previously found that in emulsion microcrystals (EMC) AgBr (I) (with silver content corresponding to pBr 4), the centers responsible for tunneling recombination at T = 77 K, with a maximum of luminescence at λmax~ 560 nm when excited from light from the absorption region of AgBr (I) EMCs (λ ~ 450 nm) as a result of temperature quenching, they undergo structural transformation into centers, which, under the same excitation, provide tunneling recombination with a wavelength depending on the binder: for EMC AgBr (I) obtained in water ‒ λmax~ 720 nm, in gelatin ‒ λmax~ 750 nm. In the present work, similar structural transformations of the centers determining tunneling recombination with λmax~ 560 nm, to the centers with luminescence on λmax~ 720 nm were implemented for AgBr (I) EMCs synthesized in polyvinyl alcohol (PVA) with an increase in the content of silver ions in the emulsion (from pBr 4 to 7). Responsible for this transformation, as follows from the obtained results, are mobile interstitial silver ions Agi +, which transform these tunnel recombination centers. The effect of the binder on the recombination processes in EMC AgBr (I) is manifested in changes in the kinetics of the increase in luminescence with λmax~ 560 nm upon excitation by light from the absorption region of AgBr (I) EMC (λ ~ 450 nm) to a stationary level. For a binder whose molecules do not interact with Ag centers Agin+, n = 1, 2 (water, PVA at pBr 4), increase in luminescence with λmax~ 560 nm occurs monotonically from zero to the maximum stationary level. For a binder (in our case, G is gelatin), whose molecules with centers Agin+ (n = 1,2) form complexes (Agin0G+), the kinetics of the increase in luminescence in EMC AgBr (I) to a stationary level at λmax~ 560 nm at pBr 4 is characterized by the presence of “flash flare”. Adsorption on the surface of EMC AgBr (I) (in PVA at pBr 7) of the dye is manifested as follows: if, before the introduction of the dye, the kinetics of the increase in luminescence with λmax~ 560 nm, when excited from light from the absorption region of AgBr (I) EMC (λ ~ 450 nm) to a stationary level, “flare-up” appeared, then after the introduction of the dye, the luminescence increases with λmax~ 560 nm occurs monotonically from zero to the maximum stationary level. Studies of the “flash” of luminescence stimulated by infrared (IR) light, after the termination of the action of exciting light, showed that when the kinetics of the increase in luminescence with λmax~ 560 nm to the stationary level, it exhibits "flare-up", a "flash" stimulated by IR light is not observed at λ ~ 560 nm. In the absence of “flash flare”, a “flash” at λ ~ 560 nm is observed. From our point of view, the results obtained indicate that “flare-up burning” is due to the presence of deep centers of electron localization with a small capture cross section, and not a photochemical reaction stimulated by exciting light. Key words: AgBr (I) microcrystals, emulsions, glow centers, luminescence flare-up.

Single molecular precursor ink for AgBiS2 thin films: synthesis and characterization

2018 ◽  
Vol 6 (28) ◽  
pp. 7642-7651 ◽  
Author(s):  
Ening Gu ◽  
Xianzhong Lin ◽  
Xiaofeng Tang ◽  
Gebhard J. Matt ◽  
Andres Osvet ◽  
...  
Keyword(s):  
Thin Films ◽  
Coordination Chemistry ◽  
Synthesis And Characterization ◽  
Band Structures ◽  
Molecular Precursor ◽  
Photoconductivity Response

The coordination chemistry of Ag–Bi–TU–DMSO molecular ink was studied. AgBiS2 thin films feature mixed band structures and show photoconductivity response.

Roles of carbon impurities and intrinsic nonradiative recombination centers on the carrier recombination processes of GaN crystals

2019 ◽  
Vol 13 (1) ◽  
pp. 012004 ◽  
Author(s):  
Kazunobu Kojima ◽  
Fumimasa Horikiri ◽  
Yoshinobu Narita ◽  
Takehiro Yoshida ◽  
Hajime Fujikura ◽  
...  
Keyword(s):  
Nonradiative Recombination ◽  
Carrier Recombination ◽  
Carbon Impurities ◽  
Recombination Processes ◽  
Recombination Centers
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