Porphyrazine: An effective receptor for quantum dots

CdSe/ZnS quantum dots (C-S QD) interact spontaneously with a designed free-base porphyrazine (H₂Pz) in toluene. Spontaneous interaction between C-S QD and H₂Pz is observed from UV-vis investigations and it may be formulated with the help of dipole-dipole transition. Fluorescence measurements reveal that the photoluminescence (PL) of C-S QD suffers a considerable extent of quenching at its emission maximum, i.e., at 612 nm following the interaction with H₂Pz. The self-assembly of H₂Pz with C-S QD is quantified with the help of the evaluation of the formation constant ($K$) value of C-S QD-H₂Pz system, i.e., $K_{C-SQD-H2Pz}$ = 1.3 × 10⁵ dm³ ⋅ mol${}^{-1}$. The estimated $k_q$ value ($k_q$ = quenching constant of C-S QD–H₂Pz system) is determined to be $\sim$ 2.47 × 10${}^{12}$ dm³/mol.sec.) suggesting a static quenching mechanism for the photoexcited decay of C-S QD by H₂Pz in solution. The results obtained from present investigations may be suitably utilized for the future application of porphyrazine as a selective host for quantum dots.