Claiming that the model is the first model of its kind I read somehere in this stack-exchange that its best to not make strong statements (such as stating the previous method is completely wrong) etc. In my paper, I thought that stating this the model I am presenting is the first model for this type of device would bolster the chances of publication. It is true that there hasn’t been any model for this type of device, atleast not to my knowledge and extensive search.

But is claiming that this is the first model too strong a statement? Is this looked down upon in academic publications?
In 1988, in their paper Quantum Hall effect devices as circuit elements, Ricketts and Kemeny presented a first circuit model for quantum Hall effect devices [1]. 

Here is how the model is presented in the abstract:


  The electrical behaviour of a quantum Hall effect device is described
  in terms of an equivalent circuit. This circuit is able to model the
  principal electrical characteristics of an ungated Hall bridge device.


In the Introduction:


  In this paper we describe the behaviour of a QHE
  device in terms of an equivalent circuit. 


And in the Conclusions:


  An equivalent circuit has been presented that can represent the DC
  electrical behaviour of a Hall bridge device under QHE conditions.


This is just a random example, but I think that it aptly shows the right way to present a first model: review what is known about that device and its behaviour, so that it becomes evident that, to your knowledge, there isn't any model of that kind currently available; tell the reader what kind of model you are going to describe and what phenomena it can model. 

Then, let the reader decide if it's really a first one.

[1] B. W. Ricketts and P. C. Kemeny, J. Phys. D: Appl. Phys., 21, 483, 1988.