Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Systematic derivation of a surface polarization model for planar
  perovskite solar cells
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin