To study the effect of energy alignment between the lower polariton mode minimum and the exciton reservoir emission, we fabricated cavities with an average quality factor (𝑄𝑄) of 70 and different detuning (𝛿𝛿 1 ≈ 14 meV and 𝛿𝛿 2 ≈ 58 meV) and measured their photoluminescence energy dispersion at both low and high pumping fluences (Figure ). First, we detuned the cavity mode by 𝛿𝛿 1 ≈ 14 meV to align the emission maxima of the neat perovskite film with the lower polariton mode minimum at �𝑘𝑘 ∥ ���⃗ � = 0. The fluence-dependent PL energy dispersion of this microcavity is displayed in Figure and, where the lower polariton branch energy aligns with the higher energy PL peak (PL1). As the excitation fluence increases, the PL of the lower polariton branch shows an accumulation to �𝑘𝑘 ∥ ���⃗ � = 0, as shown by the increasing PL intensity at lower inplane wave-vectors. However, despite the high pumping fluence assessed, no condensation was observed. The lower polariton and PL2 of the material at a pumping fluence of 0.2 mJ/ cm 2 and 8 mJ/ cm 2 , correspondingly.