While preparing films from precursor solutions, does the aging effect affect the phase purity? Without aging, the phase purity is coming but after aging, from X-ray diffraction pattern, when some extra peaks come over the real phase structure and the sample gives the good electrical properties than the real one then how to analysis the extra peaks.
Subhasri Subudhi do SEM with EDX. The EDX will tell you the "element" which is the "impurity" in your sample.
Once you have found that impurity element... u have to ensure that you can make those samples again (with the equivalent impurity composition) to ensure the reproducibility.
If you cannot do EDX (due to equipment accessibility), you need to think over your synthesis method carefully and try to guess what impurity can enter your sample... (e.g. dust is Si... can dust enter in your samples ?) If you can guess your impurity than go and check the JCPDS of that element and see if that element has the peak at 2tetha... at which you are receiving that peak... if yes than u can conclude that your impurity is that element.... but the best and most reliable method is EDX.
Dear Subhasri Subudhi ,
It is essential to be sure if the extra peaks are related to any impurity or are new reflection planes. For instance, the superstructure lattice generates new reflection peaks, not related to any new phase. They may be present in tetragonal materials due to stacking faults.
Many phases have an industrial interest by their Physico-chemical properties. However, differences in stoichiometry or symmetry, site occupancies, and interstitial ions occurrences may produce particular new properties and generate new reflection peaks. In that case, the phase is the same, associated with some physical variations.
Solid-solutions may have different properties than their components alone, so it is imperative to identify the new reflections planes' origin.
In case you already have new phases, it would be an identification task to perform. Once the principal phase is known, a careful fit of the diffraction may allow you to extract the new lattice parameters that correspond to the new reflection planes.
Since identified the new lattice (if it is only one), considering the reactants already used in the synthetic route, you may end up with a list of candidates. Variations in stoichiometry, interstitial atoms, lattice distortions, and even relative solubility phases are possibilities to be considered.
The task is a hard job, not impossible to fulfill, as your system presents several phases contributing to the observed new and exciting properties.
Best regards,
WNM
Dear Syed Waqar Hasan , Thomas Breuer
, Wagner Da Nova Mussel thank you for the information, I have modified the question as for the required answer please look into it.
Subhasri Subudhi i am not sure what do you mean by aging? if you mean u r heating the sample at any particular temperature and you refer to the duration of that heating as aging.... than yes there are many chemicals which need specific heating time to acquire particular phases.. and their properties are very good when their phase has changed. For example, when we make BiSbTe... (for thermoelectric materials), we need stoichiometric composition for which we have to keep them at elevated temperatures for pretty long duration (say 12-24 hours).. we also noted that if the heating temperature is low... or the heating duration is insufficient, the electrical conductivity and seebeck coefficient are very different from the optimized BiSbTe compounds.
And yes ofcourse; the newly formed phases will give you additional peaks at XRD.
I think that you can us X-ray fluorescence or EdX (energy dispersive x-ray analysis) to determine kind impurities
Syed Waqar Hasan Regarding to my question, the aging means keeping the precursor solution over a week at room temperature and finding some undissolved materials at the bottoms.
@ Subhasri Subudhi
EDX can be useful or one can do an elemental analysis of the Precursor solution to find out whether any impurities are present before and after aging.
Inductively Coupled Plasma Mass Spectroscopy (ICPMS). I don't know about this spectroscopy. But this will tell about the elemental traces of the impurities.
If I am wrong kindly correct me.
kindly go through these works it will help you
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