By the way, I want the emission spectrum of X in solution in order to ascertain if there are emission bands in the spectrum of the X film that are not present in the emission spectrum of X in solution. If the low-energy band that we observe in the emission spectrum of the X film is not present in the emission spectrum of the X solution, we might posit that such a band corresponds to the emission of an excimer. If that's the case, the time-dependent changes that we observe in the emission spectra of the X film can be explained away as energy transfer towards this excimer. It is reasonable to assume that such an energy transfer process would become less efficient with increasing temperature, since higher temperatures are known to disrupt the formation of excimers. Hence, we may be able to explain why the relative intensity of the low-energy emission band decreases with increasing temperature. In other words, the emission arising from the excimer decreases with increasing temperature simply because the formation of the excimer is hampered at high temperatures. The formation of the excimer is also expected to increase with increasing thickness because at higher thicknesses the material is more tightly packed. This is indeed what we observed when we characterized the X films supported on quartz.