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As one of the most important organic semiconductors, perylene diimide derivatives (PDIs) have been widely applied in optoelectronics. Two kinds of soluble PDIs with different imide substituents have been synthesized and their optical properties have been investigated. The photoluminescence (PL) intensity of the PDI with amino phenyl imide substituents (NH -PDI) is much lower than that of the PDI with octyl imide substituents (O-PDI). It can be found that the Stokes shift of O-PDI is positive, whereas, the Stokes shift of NH -PDI is negative. The emission intensity of the 0-0 electron transition relative to that of the 1-0 electron transition (I /I ) in the PL spectrum of O-PDI is decreased, but the value of I /I in the PL spectra of NH -PDI is increased as the dielectric constant of the solvent increases. The large overlap between the absorption and PL spectra plays an important role to result in the low PL intensity of NH -PDI. The PL decay data show that a non-radiative process, photoinduced electron transfer, also contributes to the low PL intensity of NH -PDI. The results can help researchers to understand the effect of the imide substituents on the optical properties of PDIs.

Perovskite C s P b B r 3 quantum dot (QD) glasses doping C u 2 + are reported for excellent long-wavelength-pass filters. Transmittance, optical density (OD), photoluminescence (PL), PL excitation, and PL decay are used to investigate filter properties and the quenching mechanism. At low C u 2 + molar concentrations of 0%, 0.0025%, 0.005%, and 0.01%, the filters exhibit good properties in transmittance and OD. Transition wavelengths are 518, 513, 513, and 512 nm, respectively. The shape and position of transmittance and OD are almost not changed. As C u 2 + concentration increases, PL intensity is monotonously quenched. PL decay is obviously faster. The quenching mechanism is dynamic quenching, which is electron transfer from QDs to C u 2 + . In comparison with the initial intensity, the intensity decreases by factors of 7.6, 12.8, and 18.8. Oxidation and reduction atmospheres are introduced, and the dynamic quenching mechanism is further confirmed. At high C u 2 + concentrations of 0.013%–0.02%, the quenching mechanism is static quenching. Double-anion C s P b ( C l / B r ) 3 QD glasses of different C u 2 + concentrations extend the operation wavelength to the blue light region. For C u 2 + concentrations of 0%, 0.005%, and 0.01%, the transition wavelengths are 470, 472, and 473 nm for C s P b ( C l / B r ) 3 (NaCl as Cl source) QD glasses, and 430, 426, and 445 nm for C s P b ( C l / B r ) 3 ( P b C l 2 as Cl source) QD glasses, respectively.

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