Hammad Cheema

14 Questions 60 Answers 0 Followers

Questions related from Hammad Cheema

Why 18-20 nm particle size TiO2 film (5 micro meter thickness roughly) turns out to be transparent after sintering?

TiO2 nanoparticles are white itself, but what is the cause of transparency after sintering?

10 December 2018 3,382 3 View

Is back electron transfer (injected electron to donor part of the sensitizer or oxidized dye) a possibility for Ru (II) sensitizers for DSSCs?

We are seeing reports of such kind of recombination for organic sensitizer, but I was wondering if something similar exists or being studied for Ru (II) sensitizers?

26 September 2016 7,670 3 View

How can I reduce the aggregation of organic dyes on TiO2 surface for DSSC?

Possible options are additions of CDCA-coadsorbate, and co-sensitization. I have tried both options, CDCA do not help a lot by increasing to 100x compared to amount of dye. Co-sensitization...

09 May 2016 681 10 View

How we can conceptualize trapping states below conduction band which can accept electrons for TiO2 based devices?

Since the distribution of these states determines the charge capacity followed by photovoltage and photocurrent in TiO2 based devices such as dye-sensitized solar cells?

13 April 2016 3,776 3 View

How can we explain the increase in excited state life time of terephthalic acid after hydroxylation?

Measured excited state life time for terephthalic acid (2.4 ns) and 2-hdyroxyl terephthalic acid (7.6ns) by TCSPC method in acetonitrile which was obtained after monoexponential fitting of the...

27 October 2015 9,449 1 View

Acetonitrile (ACN) vs. toluene as a solvent for photophysical studies of organic systems?

I measured the Nano-second transient absorption spectroscopy and singlet oxygen emission for a terephthalate based system (attached), in ACN it shows weak fluorescence emission intensity, strong...

11 August 2015 9,773 10 View

Does anyone have experience with Dimethyl terephthalate or terephthalic acid photophysics and photochemistry?

Most of the literature search for me result into hits which are either done in 1970's or late 80's. I am interested mainly in knowing about transient absorption and photophysical nature singlet,...

10 June 2015 6,244 1 View

What is causing the low fill factor of MAPbI3-spiro based solar cell, when current is around 16 mA/cm2 and Voc is 0.9V?

I had made some Perovskite solar cells, current up to 16mA/cm2 and Voc of 0.9V was achieved but FF was around 26 which was killing the efficiency, and in different cells that is consistent? can...

22 May 2015 6,439 15 View

Can we evaporate metal right after spin coating Spiro for perovskite solar cells?

Some publications now report effect of dry air storage over night for efficient results? such as Solar EnergyMaterials&SolarCells134(2015)60–63, any experience?

18 May 2015 686 4 View

Is Lead Iodide completely soluble in DMF?

I was trying to do two step sequential deposition, and even for stirring at 70C for overnight it do not dissolve completely. Eventually, after spin coating i see grains of PbI2 which are obvious...

01 May 2015 7,221 11 View

How can dipole moment effect charge separation and separated states?

For example, would photo-induced electron transfer be favored in more polar solvents compared to less polar?

06 April 2015 6,037 6 View

How can we determine the distance between cation and anion for Rehm Weller equation?

In order to determine the free enthalpy of electron transfer between donor and acceptor?

24 March 2015 2,406 1 View

How we can etch and pattern FTO glass with Zinc powder and HCl for perovskite solar cells?

How we can mask?

03 March 2015 4,008 17 View

Can anthracene and 9,10 dicyanoanthracene be used as singlet oxygen quantum yield standards?

First I would like to check the reliability of the method by measuring standard against standard, and I do have anthracene and 9,10 dicyanoanthracene in the lab.

19 February 2015 5,295 2 View