I have fabricated a planar photoconductor device with CsPbBr3 perovskite QDs as active material. The QDs emit high fluorescence under UV lamp suggesting the material is photoactive. As expected the PL intensity is also high. When the IV characteristic is measured ,the photocurrent is lower than the dark current under illumination. The dark current is 1.8E-8 A at 5 V and the photo current is 3.8E-9 A at 5V. The trend is the same when the the voltage is swept from -5 to 5V. The light source is a broadband solar simulator with a power density of 100 mW/cm2. The temperature was maintained at 25-27C. Is this due to scattering caused by other generated carriers or some phonon effect?
Conductivity under illumination is higher than the dark state since extra carriers will be obtained from excited electrons due to photons
for more details you can read the following book
optical processes in semiconductors by J I Pankove
to have extra information on the effect of nanoscale on optical properties
I suggest to see the following presentation
"Solid Surface and Nanoscale materials Structure" M. S. Omar Presentation · July 2016 with 156 Reads DOI: 10.13140/RG.2.2.31947.59684 Charmo, University of Charmo, University of Salahaddin, DOI:10.13140/RG.2.2.31947.59684
Thank you. But the conductivity is lower under illumination in this case.
check the solar simulator's emission wavelength and also check qd's absorption maxima(from uvvis analysis).
Are you getting repeated results ? May be due to increased recombination .
Hi!
Have you double checked the nature of your CsPbBr3?
The material can have a complex phase diagram, depending on several factors.
See:
Article Embedded Two-Dimensional Perovskite Nanoplatelets with Air-S...
Article Low defects, large area and high stability of all-inorganic ...
Article Defective States in Micro-Crystalline CsPbBr3 and Their Role...
And also:
https://s3-eu-west-1.amazonaws.com/itempdf74155353254prod/7629467/Luminescence_of_Polybromide_Defects_in_Cs4PbBr6_v2.pdf
There are methods to effect repair too:
Article Post-Synthesis Transformation of Insulating Cs 4 PbBr 6 Nano...
Article The Luminescence Property of CsPbxM1-xBr3 Perovskite Nanocry...
And also:
https://pubs.rsc.org/en/content/articlelanding/2019/nr/c8nr10150g/unauth#!divAbstract
Please post your progress
thanks
Rob
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