scholarly journals Energetics of Nonradiative Surface Trap States in Nanoparticles Monitored by Time-of-Flight Photoconduction Measurements on Nanoparticle–Polymer Blends

2019 ◽  
Vol 11 (40) ◽  
pp. 37184-37192
Author(s):  
Xiaoqing Guo ◽  
Qianxun Gong ◽  
Joanna Borowiec ◽  
Sijie Zhang ◽  
Shuo Han ◽  
...  
Keyword(s):  
Polymer Blends ◽  
Time Of Flight ◽  
Trap States ◽  
Surface Trap

Facet-Dependent Surface Trap States and Carrier Lifetimes of Silicon

Nano Letters ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 1952-1958 ◽  
Author(s):  
Chih-Shan Tan ◽  
Yicheng Zhao ◽  
Rong-Hao Guo ◽  
Wei-Tsung Chuang ◽  
Lih-Juann Chen ◽  
...  
Keyword(s):  
Trap States ◽  
Surface Trap ◽  
Carrier Lifetimes

Cryogenically probing the surface trap states of single nanowires passivated with self-assembled molecular monolayers

Nanoscale ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 82-86 ◽  
Author(s):  
Xingyan Zhao ◽  
Peng Tu ◽  
Jiajing He ◽  
Hong Zhu ◽  
Yaping Dan
Keyword(s):  
Trap States ◽  
Surface Trap ◽  
Molecular Monolayers ◽  
Cryogenic Technique ◽  
Single Nanowires ◽  
Self Assembled

We demonstrate a cryogenic technique that is capable of measuring the density of surface trap states in the full half bandgap without the exponential transient photoresponse assumption.

scholarly journals Mechanisms of triplet energy transfer across the inorganic nanocrystal/organic molecule interface

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiao Luo ◽  
Yaoyao Han ◽  
Zongwei Chen ◽  
Yulu Li ◽  
Guijie Liang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Organic Molecule ◽  
Transient Absorption ◽  
High Energy ◽  
Model Systems ◽  
Trap States ◽  
Triplet Energy ◽  
Surface Trap ◽  
Triplet Energy Transfer

AbstractThe mechanisms of triplet energy transfer across the inorganic nanocrystal/organic molecule interface remain poorly understood. Many seemingly contradictory results have been reported, mainly because of the complicated trap states characteristic of inorganic semiconductors and the ill-defined relative energetics between semiconductors and molecules used in these studies. Here we clarify the transfer mechanisms by performing combined transient absorption and photoluminescence measurements, both with sub-picosecond time resolution, on model systems comprising lead halide perovskite nanocrystals with very low surface trap densities as the triplet donor and polyacenes which either favour or prohibit charge transfer as the triplet acceptors. Hole transfer from nanocrystals to tetracene is energetically favoured, and hence triplet transfer proceeds via a charge separated state. In contrast, charge transfer to naphthalene is energetically unfavourable and spectroscopy shows direct triplet transfer from nanocrystals to naphthalene; nonetheless, this “direct” process could also be mediated by a high-energy, virtual charge-transfer state.

scholarly journals Improvement of Dye Solar Cell Efficiency by Photoanode Posttreatment

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tanja Ivanovska ◽  
Zoran Saponjic ◽  
Marija Radoicic ◽  
Luca Ortolani ◽  
Vittorio Morandi ◽  
...  
Keyword(s):  
Dye Sensitized Solar Cells ◽  
Trap States ◽  
Electron Recombination ◽  
Electron Hole ◽  
Surface Trap ◽  
Solar Cell Efficiency ◽  
Cell Efficiency ◽  
Dye Sensitized ◽  
Sensitized Solar Cells ◽  
Hole Recombination

The basic concept for efficiency improvement in dye-sensitized solar cells (DSSC) is limiting the electron-hole recombination. One way to approach the problem is to improve the photogenerated charge carriers lifetime and consequently reduce their recombination probability. We are reporting on a facile posttreatment of the mesoporous photoanode by using a colloidal solution of TiO2nanoparticles. We have investigated the outcome of the different sintering temperature of the posttreated photoanodes on their morphology as well as on the conversion efficiency of the DSSC. The DSSCs composed of posttreated photoanodes at 450°C showed an increase inJSCand consequently an increase in efficiency of 10%. Investigations were made to determine the electron recombination via the electrolyte by the OCVD technique. We found that the posttreatment has the effect of reducing the surface trap states and thus increases the electron lifetime, which is responsible for the increase of the overall cell efficiency.

Band Edge Recombination in CdSe, CdS and CdSxSe1−xAlloy Nanocrystals Observed by Ultrafast Fluorescence Upconversion: The Effect of Surface Trap States

2008 ◽  
Vol 112 (33) ◽  
pp. 12736-12746 ◽  
Author(s):  
Maria Danielle Garrett ◽  
Albert D. Dukes III ◽  
James R. McBride ◽  
Nathanael J. Smith ◽  
Stephen J. Pennycook ◽  
...  
Keyword(s):  
Band Edge ◽  
Trap States ◽  
Surface Trap ◽  
Fluorescence Upconversion ◽  
Effect Of Surface

scholarly journals Mitigating the charge trapping effects of D-sorbitol/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) polymer blend contacts to crystalline silicon

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Daniel Cohen ◽  
Esha Thakur ◽  
Michael G. Walter
Keyword(s):  
Polymer Blend ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Conductive Polymer ◽  
Surface Oxidation ◽  
Charge Trapping ◽  
Device Performance ◽  
Trap States ◽  
Adhesive Properties ◽  
Surface Trap

Abstract Solution-processable conductive polymers are advantageous materials for making inexpensive, electrical junctions to crystalline semiconductors. We have investigated methods to improve the device performance of hybrid solar cells made from n-type silicon and a conductive polymer glue based on a blend of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and D-sorbitol. The PEDOT:PSS blend behaves like a high work function metal creating a Schottky-type junction. The addition of D-sorbitol increases PEDOT:PSS conductivity and provides adhesive properties, allowing the top contact of the solar cell to be laminated onto the silicon substrate. Unfortunately, the addition of the D-sorbitol to the PEDOT:PSS significantly alters the shape of the measured current-voltage performance curve of a crystalline silicon (n-Si)/PEDOT:PSS junction. Under illumination, this results in a decline in the fill factor (FF) and a drop in photocurrent density (J sc) compared to PEDOT:PSS-only devices. We have discovered that the decline in device performance is likely due to surface trap states caused by D-sorbitol/silicon interaction and/or silicon oxidation. X-ray photoelectron spectroscopic (XPS) analysis shows that surface oxidation quickens, and possible silicon surface functionalization with D-sorbitol occurs while processing the D-sorbitol/PEDOT:PSS contact on H-terminated surfaces. To overcome these interface issues, the silicon surface was chemically modified using surface methylation, making it insensitive to D-sorbitol/silicon interactions and surface oxidation during the processing of the PEDOT:PSS polymer blend contact. This also enabled the crystalline silicon (n-Si)/s-PEDOT:PSS device performance to be maintained for longer periods. Using a silicon surface methylation strategy, good device performance could be achieved without changing the adhesive properties of D-sorbitol/PEDOT:PSS polymer blend.

scholarly journals Plasmon-Assisted Suppression of Surface Trap States and Enhanced Band-Edge Emission in a Bare CdTe Quantum Dot

2019 ◽  
Vol 10 (11) ◽  
pp. 2874-2878 ◽  
Author(s):  
Assegid Mengistu Flatae ◽  
Francesco Tantussi ◽  
Gabriele C. Messina ◽  
Francesco De Angelis ◽  
Mario Agio
Keyword(s):  
Quantum Dot ◽  
Band Edge ◽  
Band Edge Emission ◽  
Trap States ◽  
Edge Emission ◽  
Surface Trap ◽  
Cdte Quantum Dot
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