Sending a random email will not do anything. Patent systems are very legalistic and bureaucratic but there are procedures to attempt to accomplish your goals.
Do you have a case?
First you need advice on how strong your case is. If your work is not considered published it may not qualify as prior in one or more jurisdictions and in that case submitting it would have no effect. However, in the US for example, a thesis that is placed in the school or dept. library and indexed by subject can be considered published as of the date it is shelved. Presenting at a conference can constitute publishing, especially if material was handed out. This was a good area for edge-case bar exam questions. It probably does trigger novelty breaking in places that require absolute novelty.
As mentioned in EricS’s answer your “publication” date (however that determined) must be before the earliest claimed priority date of the set of applications to actually be prior art.
What counts as prior art
Consider the US -
In the US before AIA
"the invention was known or used by others in this country, or patented or described in a printed publication in this or a foreign country, before the invention thereof by the applicant for patent"
was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public
After the a lot hinges on the technicality of "published". There are many cases of almost simultaneous invention and the patent world now decides who wins by first-to-file, assuming no prior publication. In that case you loose. If you are considered to have published before anyone filed everyone looses in most jurisdictions.
Pre AIA the US had a way to try to show you were the first to conceive. Even if you didn't file first you could still get the patent. That was eliminated by the AIA.
If your work is not considered published you have a lower chance of invaliding others' patents. If is is considered published then others' patents might be invalidated but you will not get any patent rights in anyplace requiring absolute novelty (most of the world except the US.) There are different issues if you have evidence another party took your ideas and filed as if they were the true inventors. In the US there is a Derivation procedure to address this but it is little used to-date.
If you have good prior art
This Ask Patents site was created after the AIA law was passed because it changed US patent law in a way that helped surface prior art. The provision that sparked the creation of Ask Patents was its Third-Party Preissuance Submissions section.
For the first time the public could anonymously and at no cost submit prior art to the USPTO in a way that an examiner was required to consider the submission. The then director, David Kappos, worked with google and SE to set this site up so people with knowledge of software history could gather prior art and make these new submissions. The rules require the submission must be made within a set time -
A third-party preissuance submission statutorily must be made in a patent application
before the earlier of: (a) the date a notice of allowance under 35 U.S.C. 151 is given or
mailed in the application; or (b) the later of (i) six months after the date on which the
application is first published under 35 U.S.C. 122 by the Office, or (ii) the date of the first
rejection under 35 U.S.C. 132 of any claim by the examiner during the examination of the
In much of the rest of the world there is a longer period during examination where third parties can submit "observations" at no cost. A link to the EPO process. If it is too late for a third-party submission in the US but an EPO observation is timely, filing the EPO observation will bring the prior art to the attention of the applicant’s representative who will then have an ethical and legal duty to provide it to the examiner in the US, a clever way to get it seen by the US examiner.
If it is too late for those paths, you might still be in the time window for an opposition. See the EPO process. It is not free but occurs after substantive examination and allowance but before actual issuance. It is available in multiple places, but not in the US.
If patents are already issued there are still ways of trying to get them invalidated. The costs are much higher at this point. Rather than getting them invalidated you may have the possibility in the US of having them assigned to you or your institution.