Dear Aditya Bhardwaj ,

What do you want to obtain? Which type of the I-V curve you would like to get? Which device do want to produce?

Silver paste behaves metallic and the

Best wishes FTO behaves as semimetal.

When you contact them you get an ohmic contact.

You will never get a rectifying I-V characteristics.

Best wishes

Respected sir, Abdelhalim abdelnaby Zekry I want to measure the I-V response for halide perovskite material by using FTO as the bottom electrode and Silver paste as the top electrode, but when I fabricate the device, I am unable to get any variation by light illumination. Could you let me know what could be the reasons for not getting the current-voltage characteristic?

@Aditya Bhardwaj Silver paste has solvent content. It is not easy to get a nice pattern though. Sometimes it is easy to get a short circuit due to the spreading into another electrode. Why not use printable silver nanoparticles ink as alternative to silver paste? It should work well.

Dear@ Aditya,

welcome again!

To study the optoelectronic properties of the perovskite material you have two solutions:

- One solution is to deposit the perovskite on an insulting glass and providing it with two metallic electrodes by the silver paste. In this way you get a photoconductor its resistance will decrease by the illumination.

- The other solution is to etch part of the FTO such that you form two separate electrodes and deposit on it the perovskite layer. In this case the perovskite layer will act as a bridge between the two FTO electrodes.

Depositing perovskite directly on FTO will affect much the conduction in the perovskite layer. It may short-circuit the perovskite layer and it will in this way insensitive to the incident light.

Best wishes

Thank you, sir, Abdelhalim abdelnaby Zekry for your valuable suggestions.

Dear professor Abdelhalim abdelnaby Zekry,

I want to ask you question is dependent on the photodetector,

my question is : do we can make photodetector only with the n-type or p-type junction. (I mean not p-n junction ).

Dear Beddiar Mohammed Ismail

Welcome!

peace upon you!

Yes you can make a photodetector using any sheet or a film of a semicondcutor material. The material can have p-type , n-type doping or intrinsic. As the doping decreases the photodetector will be more sensitive since its dark current decreases. So, the best material is the intrinsic semicondcutor since it has the smallest dark current as it has very few intrinsic carrier concentrations.

Such detectors are called photoconductors or light dependent resistance.

They are commertial devices and you can get them from the electronics market.

Best wishes

Thank you, sir, Abdelhalim abdelnaby Zekry for your answer.

in this end, why do we need p-n junction to generate current .and we know that any sheet or a film of a semiconductor p-type, n-type doping or intrinsic. can generate current? Abdelhalim abdelnaby Zekry