Isolated prompt photon purity as a function of cluster $p_{\rm T}$. The purity in p-Pb collisions at $\snn=5.02$ TeV(left) is calculated using the template fit approach, whereas for $\snn= 8 $ and $8.16$ TeV (right) the purity is obtained using the ABCD method. The purity is fitted using a modified sigmoid function given in Eq. 11 and an error function for $\snn=5.02$ TeV. Vertical lines and boxes denote statistical and systematic uncertainties, respectively.